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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

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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

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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

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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

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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 (Yap1^LKO) 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

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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

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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

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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

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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

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Efficient dechlorination of 2,4-dichlorophenol in an aqueous media with a mild pH using a Pd/TiO

Jiangkun DU,Jianguo BAO,Wei HU

《环境科学与工程前沿（英文）》 2015年第9卷第5期页码 919-928 doi: 10.1007/s11783-015-0794-x

摘要： In this study, palladium-loaded titania nanotubes was fabricated on a titanium plate (Pd/TiO NTs/Ti) for efficient electrodechlorination of 2,4-chlorophenol with a mild pH condition. The nature of Pd/TiO NTs/Ti electrodes was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques. The characterization results indicated the generation of Pd nanoparticles which were evenly dispersed on titania nanotubes arrays on the Pd/TiO NTs/Ti surface. An effective degradation efficiency of up to 91% was achieved within 60 min at cathode potential of −0.7 V ( SCE) and initial pH of 5.5. The effects of the applied cathode potential and initial pH on the degradation efficiency were studied. A near neutral condition was more favorable since very low and very high pHs were not conducive to the dechlorination process. Furthermore, the intermediates analysis showed that the Pd/TiO NTs/Ti electrode could completely remove chlorine from 2, 4-dichlorophenol since only phenol was detected as the byproduct and the concentration of released chlorine ions indicated near-complete dechlorination. This work presents a good alternative technique for eliminating persistent chlorophenols in polluted wastewater without maintaining strong acidic environment.

关键词： Pd/TiO₂NTs/Ti cathode chlorophenols electrocatalytic dechlorination wastewater treatment

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Activation of phagocytosis by immune checkpoint blockade

null

《医学前沿（英文）》 2018年第12卷第4期页码 473-480 doi: 10.1007/s11684-018-0657-5

摘要：

Inhibition of macrophage-mediated phagocytosis has emerged as an essential mechanism for tumor immune evasion. One mechanism inhibiting the innate response is the presence of the macrophage inhibitory molecule, signal regulatory protein-α (SIRPα), on tumor-associated macrophages (TAMs) and its cognate ligand cluster of differentiation 47 (CD47) on tumor cells in the tumor microenvironment. On the basis of a recently discovered programmed death protein 1 (PD-1) in TAMs, we discuss the potential inhibitory receptors that possess new functions beyond T cell exhaustion in this review. As more and more immune receptors are found to be expressed on TAMs, the corresponding therapies may also stimulate macrophages for phagocytosis and thereby provide extra anti-tumor benefits in cancer therapy. Therefore, identification of biomarkers and combinatorial therapeutic strategies, have the potential to improve the efficacy and safety profiles of current immunotherapies.

关键词： CD47 PD-1 PD-L1 immunotherapy TAM phagocytosis macrophage

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Highly active and durable Pd-Cu catalysts for oxygen reduction in alkaline exchange membrane fuel cells

Xiong PENG, Travis J. OMASTA, Justin M. ROLLER, William E. MUSTAIN

《能源前沿（英文）》 2017年第11卷第3期页码 299-309 doi: 10.1007/s11708-017-0495-1

摘要： A Pd-Cu catalyst, with primary B2-type phase, supported by VulcanXC-7R carbon was synthesized via a solvothermal method. The catalysts were physically and electrochemically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and both cyclic and linear sweep voltammetry using a rotating disk electrode (RDE). During the RDE testing, the half-wave potential of the Pd-Cu/Vulcan catalyst was 50 mV higher compared to that of commercial Pt/C catalyst for the oxygen reduction reaction (ORR) in alkaline media. The Pd-Cu/Vulcan exhibited a specific activity of 1.27 mA/cm and a mass activity of 0.59 A/mg at 0.9 V, which were 4 and 3 times greater than that of the commercial Pt/C catalyst, respectively. The Pd-Cu/Vulcan catalyst also showed higher alkaline exchange membrane fuel cell (AEMFC) performance, with operating power densities of 1100 MW/cm operating on H /O and 700 MW/cm operating on H /Air (CO -free), which were markedly higher than those of the commercial Pt/C. The Pd-Cu/Vulcan catalyst also exhibited high stability during a short-term, AEMFC durability test, with only around 11% performance loss after 30 hours of operation, an improvement over most AEMFCs reported in the literature to date.

关键词： alkaline exchange membrane (AEM) fuel cell Pd-Cu oxygen reduction high performance water

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Pd-Fe/α-Al

Shengping WANG, Xin ZHANG, Yujun ZHAO, Yadong GE, Jing LV, Baowei WANG, Xinbin MA

《化学科学与工程前沿（英文）》 2012年第6卷第3期页码 259-269 doi: 10.1007/s11705-012-1212-6

摘要： Cordierite monoliths coated with Pd-Fe/α-Al O catalysts were prepared at various calcination temperatures and characterized by thermogravimetry, temperature-programmed reduction, transmission electron microscopy, diffuse reflectance infrared Fourier transformation spectroscopy and X-ray diffraction. The performance of the catalytic monoliths for the synthesis of dimethyl oxalate (DMO) through a CO coupling reaction was evaluated. Monolithic catalysts with calcination temperatures ranging from 473 K to 673 K exhibited excellent dispersion of Pd, good CO adsorption properties, and excellent performance for the coupling reaction. The optimized monolithic catalyst exhibited a much higher Pd efficiency (denoted as DMO (g)·Pd (g) ·h ) (733 h ) than that of the granular catalyst (60.2 h ), which can be attributed to its honeycomb structure and the large pore sizes in the α-Al O washcoat which was accompanied with an even distribution of the active component in the coating layer along the monoliths channels.

关键词： dimethyl oxalate coupling Pd cordierite monolith calcination structure

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Concentrations of anthropogenic Pt and Pd in urban roadside soils in Xuzhou, China

WANG Xuesong, SUN Cheng

《环境科学与工程前沿（英文）》 2008年第2卷第4期页码 475-479 doi: 10.1007/s11783-008-0071-3

摘要： The potential accumulation of platinum group elements (PGE) in the environment from automobile catalysts is high in urban areas, with the major sinks being roadside soils. Therefore, this investigation presented the detailed study on characterized concentrations of Pt and Pd and their enrichment ratios in urban roadside soils in Xuzhou, China in March 2003. Data from 21 roadside topsoil samples analyzed by inductively coupled plasma-mass spectrometer (ICP-MS) illustrated that the medians of concentrations of Pt and Pd were 2.9 and 2.8 ng/g, respectively. Hierarchical clustering analysis indicated that Pt and Pd were mainly from traffic emissions. Compared to unpolluted soils, computation of Pt and Pd enrichment ratios suggested that the Xuzhou roadside soils had average enrichment factors of 3.53 for Pt (in range of 1.22–5.73) and of 3.37 for Pd (in range of 1.35–4.46). Lower Pt/Pd ratios (in range of 0.35–2.86) in relation to similar studies in other countries were observed, which might be due to the different Pt/Pd ratios in Chinese automobile catalytic converters. Moreover, fine fraction (<250 ?m) contained higher concentrations of Pt and Pd compared to the coarse fraction (250–500 ?m).

关键词： platinum detailed different Hierarchical automobile catalytic

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Effects of Pd doping on N

Mingxin Dong, Jun Wang, Jinxin Zhu, Jianqiang Wang, Wulin Wang, Meiqing Shen

《环境科学与工程前沿（英文）》 2017年第11卷第6期 doi: 10.1007/s11783-017-0976-9

摘要： N O is a powerful greenhouse gas and plays an important role in destructing the ozone layer. This present work investigated the effects of Pd doping on N O formation over Pt/BaO/Al O catalyst. Three types of catalysts, Pt/BaO/Al O , Pt/Pd mechanical mixing catalyst (Pt/BaO/Al O +Pd/Al O ) and Pt-Pd co-impregnation catalyst (Pt-Pd/BaO/Al O ) were prepared by incipient wetness impregnation method. These catalysts were first evaluated in NSR activity tests using H /CO as reductants and then carefully characterized by BET, CO chemisorption, CO-DRIFTs and H -TPR techniques. In addition, temperature programmed reactions of NO with H /CO were conducted to obtain further information about N O formation mechanism. Compared with Pt/BaO/Al O , (Pt/BaO/Al O +Pd/Al O ) produced less N O and more NH during NO storage and reduction process, while an opposite trend was found over (Pt-Pd/BaO/Al O +Al O ). Temperature programmed reactions of NO with H /CO results showed that Pd/Al O component in (Pt/BaO/Al O +Pd/Al O ) played an important role in NO reduction to NH , and the formed NH could reduce NO to N leading to a decrease in N O formation. Most of N O formed over (Pt-Pd/BaO/Al O +Al O ) was originated from Pd/BaO/Al O component. H -TPR results indicated Pd-Ba interaction resulted in more difficult-to-reduce PdO species over Pd/BaO/Al O , which inhibits the NO dissociation and thus drives the selectivity to N O in NO reduction.

关键词： NO_x storage reduction Pt/BaO/Al₂O₃ Pd doping N₂O formation Optimization