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A new fracture criterion for peridynamic and dual-horizon peridynamics

Jinhai ZHAO, Hesheng TANG, Songtao XUE

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 629-641 doi: 10.1007/s11709-017-0447-1

摘要: A new fracture criterion based on the crack opening displacement for peridynamic (PD) and dual-horizon peridynamics (DH-PD) is proposed. When the relative deformation of the PD bond between the particles reaches the critical crack tip opening displacement of the fracture mechanics, we assume that the bond force vanishes. A new damage rule similar to the local damage rule in conventional PD is introduced to simulate fracture. The new formulation is developed for a linear elastic solid though the extension to nonlinear materials is straightforward. The performance of the new fracture criterion is demonstrated by four examples, i.e. a bilateral crack problem, double parallel crack, monoclinic crack and the double inclined crack. The results are compared to experimental data and the results obtained by other computational methods.

关键词: Castigliano’s theorem     breaking energy     critical extension     XFEM     COD     PD-COD    

mechanisms of key functional microorganisms in the partial denitrification-anammox process induced by COD

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1703-3

摘要:

● The availability of PD-anammox was investigated with higher NO3–N concentration.

关键词: PD-anammox process     Nitrite accumulation     COD     Microbial interaction    

Synthesis, physicochemical characterizations and catalytic performance of Pd/carbon-zeolite and Pd/carbon-CeO

Zeinab JAMALZADEH, Mohammad HAGHIGHI, Nazli ASGARI

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 365-381 doi: 10.1007/s11783-013-0520-5

摘要: In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/carbon-zeolite and Pd/carbon-CeO nanocatalysts. Activated carbon was obtained from pine cone chemically activated using ZnCl and modified by H PO . Natural zeolite of clinoptilolite was modified by acid treatment with HCl, while nano-ceria was synthesized via redox method. Mixed supports of carbon-zeolite and carbon-ceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller surface area (BET), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation of nano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts (~1000 m ·g ). FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100°C–250°C. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds (VOCs), representing high catalytic performance of 98% for the abatement of xylene at 250°C. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocatalysts.

关键词: Pd/carbon-CeO2     Pd/carbon-zeolite     pine cone     ZnCl2     catalytic oxidation     xylene    

Nitrate removal to its fate in wetland mesocosm filled with sponge iron: Impact of influent COD/N ratio

Zhihao Si, Xinshan Song, Xin Cao, Yuhui Wang, Yifei Wang, Yufeng Zhao, Xiaoyan Ge, Awet Arefe Tesfahunegn

《环境科学与工程前沿(英文)》 2020年 第14卷 第1期 doi: 10.1007/s11783-019-1183-7

摘要: CW-Fe allowed a high-performance of NO3‒-N removal at the COD/N ratio of 0. Higher COD/N resulted in lower chem-denitrification and higher bio-denitrification. The application of s-Fe0 contributed to TIN removal in wetland mesocosm. s-Fe0 changed the main denitrifiers in wetland mesocosm. Sponge iron (s-Fe0) is a porous metal with the potential to be an electron donor for denitrification. This study aims to evaluate the feasibility of using s-Fe0 as the substrate of wetland mesocosms. Here, wetland mesocosms with the addition of s-Fe0 particles (CW-Fe) and a blank control group (CW-CK) were established. The NO3‒-N reduction property and water quality parameters (pH, DO, and ORP) were examined at three COD/N ratios (0, 5, and 10). Results showed that the NO3‒-N removal efficiencies were significantly increased by 6.6 to 58.9% in the presence of s-Fe0. NH4+-N was mainly produced by chemical denitrification, and approximately 50% of the NO3‒-N was reduced to NH4+-N, at the COD/ratio of 0. An increase of the influent COD/N ratio resulted in lower chemical denitrification and higher bio-denitrification. Although chemical denitrification mediated by s-Fe0 led to an accumulation of NH4+-N at COD/N ratios of 0 and 5, the TIN removal efficiencies increased by 4.5%‒12.4%. Moreover, the effluent pH, DO, and ORP values showed a significant negative correlation with total Fe and Fe (II) (P<0.01). High-throughput sequencing analysis indicated that Trichococcus (77.2%) was the most abundant microorganism in the CW-Fe mesocosm, while Thauera, Zoogloea, and Herbaspirillum were the primary denitrifying bacteria. The denitrifiers, Simplicispira, Dechloromonas, and Denitratisoma, were the dominant bacteria for CW-CK. This study provides a valuable method and an improved understanding of NO3‒-N reduction characteristics of s-Fe0 in a wetland mesocosm.

关键词: Sponge iron     Wetland mesocosm     Electronic donor     Denitrification     COD/N ratio    

Metabolic interventions combined with CTLA-4 and PD-1/PD-L1 blockade for the treatment of tumors: mechanisms

《医学前沿(英文)》   页码 805-822 doi: 10.1007/s11684-023-1025-7

摘要: Immunotherapies based on immune checkpoint blockade (ICB) have significantly improved patient outcomes and offered new approaches to cancer therapy over the past decade. To date, immune checkpoint inhibitors (ICIs) of CTLA-4 and PD-1/PD-L1 represent the main class of immunotherapy. Blockade of CTLA-4 and PD-1/PD-L1 has shown remarkable efficacy in several specific types of cancers, however, a large subset of refractory patients presents poor responsiveness to ICB therapy; and the underlying mechanism remains elusive. Recently, numerous studies have revealed that metabolic reprogramming of tumor cells restrains immune responses by remodeling the tumor microenvironment (TME) with various products of metabolism, and combination therapies involving metabolic inhibitors and ICIs provide new approaches to cancer therapy. Nevertheless, a systematic summary is lacking regarding the manner by which different targetable metabolic pathways regulate immune checkpoints to overcome ICI resistance. Here, we demonstrate the generalized mechanism of targeting cancer metabolism at three crucial immune checkpoints (CTLA-4, PD-1, and PD-L1) to influence ICB therapy and propose potential combined immunotherapeutic strategies co-targeting tumor metabolic pathways and immune checkpoints.

关键词: CTLA-4     PD-1     PD-L1     immune checkpoint blockade (ICB)     metabolic reprogramming     combined tumor therapeutic strategies    

PD-1/PD-L1 blockade in cervical cancer: current studies and perspectives

Yumeng Wang, Guiling Li

《医学前沿(英文)》 2019年 第13卷 第4期   页码 438-450 doi: 10.1007/s11684-018-0674-4

摘要: Cervical cancer (CC) is the fourth most commonly diagnosed female malignancy and a leading cause of cancer-related mortality worldwide, especially in developing countries. Despite the use of advanced screening and preventive vaccines, more than half of all CC cases are diagnosed at advanced stages, when therapeutic options are extremely limited and side effects are severe. Given these circumstances, new and effective treatments are needed. In recent years, exciting progress has been made in immunotherapies, including the rapid development of immune checkpoint inhibitors. Checkpoint blockades targeting the PD-1/PD-L1 axis have achieved effective clinical responses with acceptable toxicity by suppressing tumor progression and improving survival in several tumor types. In this review, we summarize recent advances in our understanding of the PD-1/PD-L1 signaling pathway, including the expression patterns of PD-1/PD-L1 and potential PD-1/PD-L1-related therapeutic strategies for CC.

关键词: PD-1     PD-L1     immune checkpoint blockade antibody     immunotherapy     cervical cancer    

microflora and its bioaugmentation on anaerobic wastewater treatment for enhancing methane production and COD

Chong Liu, Jianzheng Li, Shuo Wang, Loring Nies

《环境科学与工程前沿(英文)》 2016年 第10卷 第4期 doi: 10.1007/s11783-016-0856-8

摘要: Syntrophic propionate-oxidizing microflora B83 was enriched from anaerobic sludge. The bioaugmentation of microflora B83 were evaluated from wastewater treatment. Methane yield and COD removal were enhanced by bioaugmentation of microflora B83. Hydrogen-producing acetogensis was a rate-limiting step in methane fermentation. Methane fermentation process can be restricted and even destroyed by the accumulation of propionate because it is the most difficult to be anaerobically oxidized among the volatile fatty acids produced by acetogenesis. To enhance anaerobic wastewater treatment process for methane production and COD removal, a syntrophic propionate-oxidizing microflora B83 was obtained from an anaerobic activated sludge by enrichment with propionate. The inoculation of microflora B83, with a 1:9 ratio of bacteria number to that of the activated sludge, could enhance the methane production from glucose by 2.5 times. With the same inoculation dosage of the microflora B83, COD removal in organic wastewater treatment process was improved from 75.6% to 86.6%, while the specific methane production by COD removal was increased by 2.7 times. Hydrogen-producing acetogenesis appeared to be a rate-limiting step in methane fermentation, and the enhancement of hydrogen-producing acetogens in the anaerobic wastewater treatment process had improved not only the hydrogen-producing acetogenesis but also the acidogenesis and methanogenesis.

关键词: Anaerobic wastewater treatment     Methane production     Hydrogen-producing acetogenesis     Methanogenesis     Rate-limiting step     Bioaugmentation    

Promoting effect of Zr on the catalytic combustion of methane over Pd/γ-Al

Hongbo NA,Tianle ZHU,Zhiming LIU,Yifei SUN

《环境科学与工程前沿(英文)》 2014年 第8卷 第5期   页码 659-665 doi: 10.1007/s11783-013-0613-1

摘要: The effect of Zr on the catalytic performance of Pd/γ-Al O for the methane combustion was investigated. The results show that the addition of Zr can improve the activity and stability of Pd/γ-Al O catalyst, which, based on the catalyst characterization (N adsorption, XRD, CO-Chemisorption, XPS, CH -TPR and O -TPO), is ascribed to the interaction between Pd and Zr. The active phase of methane combustion over supported palladium catalyst is the Pd /Pd mixture. Zr addition inhibits Pd aggregation and enhances the redox properties of active phase Pd / Pd . H reduction could effectively reduce the oxidation degree of Pd species and regenerate the active sites (Pd / Pd ).

关键词: Pd-Zr/Al2O3     methane     catalytic combustion     catalyst regeneration    

Dihydroartemisinin increased the abundance of by YAP1 depression that sensitizes hepatocellular carcinoma to anti-PD

《医学前沿(英文)》 2023年 第17卷 第4期   页码 729-746 doi: 10.1007/s11684-022-0978-2

摘要: The effect of anti-programmed cell death 1 (anti-PD-1) immunotherapy is limited in patients with hepatocellular carcinoma (HCC). Yes-associated protein 1 (YAP1) expression increased in liver tumor cells in early HCC, and Akkermansia muciniphila abundance decreased in the colon. The response to anti-PD-1 treatment is associated with A. muciniphila abundance in many tumors. However, the interaction between A. muciniphila abundance and YAP1 expression remains unclear in HCC. Here, anti-PD-1 treatment decreased A. muciniphila abundance in the colon, but increased YAP1 expression in the tumor cells by mice with liver tumors in situ. Mechanistically, hepatocyte-specific Yap1 knockout (Yap1LKO) maintained bile acid homeostasis in the liver, resulting in an increased abundance of A. muciniphila in the colon. Yap1 knockout enhanced anti-PD-1 efficacy. Therefore, YAP1 inhibition is a potential target for increasing A. muciniphila abundance to promote anti-PD-1 efficacy in liver tumors. Dihydroartemisinin (DHA), acting as YAP1 inhibitor, increased A. muciniphila abundance to sensitize anti-PD-1 therapy. A. muciniphila by gavage increased the number and activation of CD8+ T cells in liver tumor niches during DHA treatment or combination with anti-PD-1. Our findings suggested that the combination anti-PD-1 with DHA is an effective strategy for liver tumor treatment.

关键词: hepatocellular carcinoma     YAP1     Akkermansia muciniphila     anti-PD-1     dihydroartemisinin     bile acid    

Characterization of CANON reactor performance and microbial community shifts with elevated COD/N ratios

Yao Zhang, Yayi Wang, Yuan Yan, Haicheng Han, Min Wu

《环境科学与工程前沿(英文)》 2019年 第13卷 第1期 doi: 10.1007/s11783-019-1095-6

摘要:

COD/N at low ratios (0–0.82) improved N removals of CANON.

CANON performance decreased after COD/N up to 0.82.

The relative abundance of AOB decreased continuously with increasing COD/N.

AOB outcompeted at a high COD load led to CANON failure.

The relative abundance of AnAOB decreased and increased with increasing COD/N.

关键词: CANON process     COD/N ratio     Anammox     Ammonia oxidizing bacteria     Aerobic heterotrophic bacteria    

Biotoxicity evaluation of zinc oxide nanoparticles on bacterial performance of activated sludge at COD

《环境科学与工程前沿(英文)》 2022年 第16卷 第2期 doi: 10.1007/s11783-021-1453-z

摘要:

• ZnO-NP disrupted metabolic/catabolic balance of bacteria by affecting DHA activity.

关键词: Granular sludge     Biotoxicity     Reactive oxygen species     Extracellular polymeric substances    

A study on the catalytic performance of Pd/γ-Al

Ruizhi CHU, Xianyong WEI, Zhimin ZONG, Wenjia ZHAO

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 452-456 doi: 10.1007/s11705-010-0522-9

摘要: A series of Pd/γ-Al O hybrid catalysts were prepared by impregnation and subsequent calcination under microwave irradiation. The catalysts were used for direct synthesis of dimethylether (DME) from syngas. The results show that calcination under microwave irradiation improved both the activity and selectivity of the catalysts for DME synthesis. The optimum power of the microwave was determined to be 420 W. Under such optimum conditions, CO conversion, DME selectivity and time space yield of DME were 60.1%, 67.0%, and 21.5 mmol·mL ·h , respectively. Based on various characterizations such as nitrogen physisorption, X-ray diffraction, CO-temperature-programmed desorption, and Fourier transform infrared spectral analysis, the promotional effect of the microwave irradiation on the catalytic property was mainly attributed to both the higher dispersion of Pd and the significant increase in the adsorption on the CO-bridge of Pd. Microwave irradiation with very high power led to the increase in CO-bridge adsorption and thereby decreased the catalytic activity, whereas the coverage by metallic Pd of the active sites on acidic γ-Al O significantly occurred under microwave irradiation with very low power, resulting in a decrease in the selectivity to DME.

关键词: Pd/γ-Al2O3     direct synthesis     dimethyl ether     calcination under microwave irradiation    

Selective hydrogenation of acetylene over Pd/CeO

Kai Li, Tengteng Lyu, Junyi He, Ben W. L. Jang

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 929-936 doi: 10.1007/s11705-019-1912-2

摘要: Five hundred ppm Pd/CeO catalyst was prepared and evaluated in selective hydrogenation of acetylene in large excess of ethylene since ceria has been recently found to be a reasonable stand-alone catalyst for this reaction. Pd/CeO catalyst could be activated by the feed gas during reactions and the catalyst without reduction showed much better ethylene selectivity than the reduced one in the high temperature range due to the formation of oxygen vacancies by reduction. Excellent ethylene selectivity of ~100% was obtained in the whole reaction temperature range of 50°C–200°C for samples calcined at temperatures of 600°C and 800°C. This could be ascribed to the formation of Pd Ce O or Pd-O-Ce surface species based on the X-ray diffraction and X-ray photoelectron spectroscopy results, indicating the strong interaction between palladium and ceria.

关键词: selective hydrogenation     acetylene     Pd/CeO2     strong interaction    

Mechanism of methanol decomposition on the Pd/WC(0001) surface unveiled by first-principles calculations

Jinhua Zhang, Yuanbin She

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 1052-1064 doi: 10.1007/s11705-019-1908-y

摘要: In this study, the decomposition of methanol into the CO and H species on the Pd/tungsten carbide (WC)(0001) surface is systematically investigated using periodic density functional theory (DFT) calculations. The possible reaction pathways and intermediates are determined. The results reveal that saturated molecules, i.e., methanol and formaldehyde, adsorb weakly on the Pd/WC(0001) surface. Both CO and H prefer three-fold sites, with adsorption energies of ‒1.51 and ‒2.67 eV, respectively. On the other hand, CH O stably binds at three-fold and bridge sites, with an adsorption energy of ‒2.58 eV. However, most of the other intermediates tend to adsorb to the surface with the carbon and oxygen atoms in their sp and hydroxyl-like configurations, respectively. Hence, the C atom of CH OH preferentially attaches to the top sites, CHOH and CH O adsorb at the bridge sites, while COH and CHO occupy the three-fold sites. The DFT calculations indicate that the rupture of the initial C–H bond promotes the decomposition of CH OH and CH OH, whereas in the case of CHOH, O–H bond scission is favored over the C–H bond rupture. Thus, the most probable methanol decomposition pathway on the Pd/WC(0001) surface is CH OH → CH OH → -CHOH → CHO → CO. The present study demonstrates that the synergistic effect of WC (as carrier) and Pd (as catalyst) alters the CH OH decomposition pathway and reduces the noble metal utilization.

关键词: density functional theory     methanol     direct methanol fuel cells     WC(0001)-supported Pd monolayer     decomposition mechanism    

A comparison of the catalytic hydrogenation of 2-amylanthraquinone and 2-ethylanthraquinone over a Pd

Enxian Yuan, Xiangwei Ren, Li Wang, Wentao Zhao

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 177-184 doi: 10.1007/s11705-016-1604-0

摘要: The hydrogenation of 2-ethylanthraquinone (eAQ), 2- -amylanthraquinone (taAQ) and their mixtures with molar ratios of 1:1 and 1:2 to the corresponding hydroquinones (eAQH and taAQH ) were studied over a Pd/Al O catalyst in a semi-batch slurry reactor at 60 °C and at 0.3 MPa. Compared to eAQ, TaAQ exhibited a significantly slower hydrogenation rate (about half) but had a higher maximum yield of H O and a smaller amount of degradation products. This can be ascribed to the longer and branched side chain in taAQ, which limits its accessibility to the Pd surface and its diffusion through the pores of the catalyst. Density functional theory calculations showed that it is more difficult for taAQ to adsorb onto a Pd (111) surface than for eAQ. The hydrogenation of the eAQ/taAQ mixtures had the slowest rates, lowest H O yields and the highest amounts of degradation products.

关键词: hydrogenation     hydrogen peroxide     anthraquinone     Pd catalyst     AO process    

标题 作者 时间 类型 操作

A new fracture criterion for peridynamic and dual-horizon peridynamics

Jinhai ZHAO, Hesheng TANG, Songtao XUE

期刊论文

mechanisms of key functional microorganisms in the partial denitrification-anammox process induced by COD

期刊论文

Synthesis, physicochemical characterizations and catalytic performance of Pd/carbon-zeolite and Pd/carbon-CeO

Zeinab JAMALZADEH, Mohammad HAGHIGHI, Nazli ASGARI

期刊论文

Nitrate removal to its fate in wetland mesocosm filled with sponge iron: Impact of influent COD/N ratio

Zhihao Si, Xinshan Song, Xin Cao, Yuhui Wang, Yifei Wang, Yufeng Zhao, Xiaoyan Ge, Awet Arefe Tesfahunegn

期刊论文

Metabolic interventions combined with CTLA-4 and PD-1/PD-L1 blockade for the treatment of tumors: mechanisms

期刊论文

PD-1/PD-L1 blockade in cervical cancer: current studies and perspectives

Yumeng Wang, Guiling Li

期刊论文

microflora and its bioaugmentation on anaerobic wastewater treatment for enhancing methane production and COD

Chong Liu, Jianzheng Li, Shuo Wang, Loring Nies

期刊论文

Promoting effect of Zr on the catalytic combustion of methane over Pd/γ-Al

Hongbo NA,Tianle ZHU,Zhiming LIU,Yifei SUN

期刊论文

Dihydroartemisinin increased the abundance of by YAP1 depression that sensitizes hepatocellular carcinoma to anti-PD

期刊论文

Characterization of CANON reactor performance and microbial community shifts with elevated COD/N ratios

Yao Zhang, Yayi Wang, Yuan Yan, Haicheng Han, Min Wu

期刊论文

Biotoxicity evaluation of zinc oxide nanoparticles on bacterial performance of activated sludge at COD

期刊论文

A study on the catalytic performance of Pd/γ-Al

Ruizhi CHU, Xianyong WEI, Zhimin ZONG, Wenjia ZHAO

期刊论文

Selective hydrogenation of acetylene over Pd/CeO

Kai Li, Tengteng Lyu, Junyi He, Ben W. L. Jang

期刊论文

Mechanism of methanol decomposition on the Pd/WC(0001) surface unveiled by first-principles calculations

Jinhua Zhang, Yuanbin She

期刊论文

A comparison of the catalytic hydrogenation of 2-amylanthraquinone and 2-ethylanthraquinone over a Pd

Enxian Yuan, Xiangwei Ren, Li Wang, Wentao Zhao

期刊论文