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Properties and effect of forming sewage sludge into lightweight ceramics

Min YUE, Qinyan YUE, Yuanfeng QI, Baoyu GAO, Hui YU

《环境科学与工程前沿(英文)》 2012年 第6卷 第1期   页码 117-124 doi: 10.1007/s11783-010-0220-3

摘要: In this work we investigated the chemical, thermal and toxic properties of dried sewage sludge (DSS), the preparation and properties of lightweight sludge ceramic (LSC) and the mechanisms of action of the organic and inorganic foaming agents (OFAs and IFAs). The chemical components and thermal properties of the raw materials were studied by Energy Dispersive X-ray Detection (EDX) and Thermogravimetric Analysis and Differential Scanning Calorimetry (DSC/TGA). The mineral phases of the raw materials and the formed ceramics were determined by X-ray Diffraction (XRD). The leaching characteristics of heavy metals were investigated with Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Different ratios of DSS and clay were mixed and pressed into raw pellets. After drying and preheating treatment, the raw pellets were sintered at 1150°C for 10 min. The physical properties of LSC (50 wt% DSS added) were tested. The results showed that when the addition of DSS was above 50 wt%, LSC began to shrink, and a maximum density occurred. The environmental safety of LSC was satisfactory. XRD showed that some new mineral phases formed in the LSC. Observation of the microstructure by Scanning Electron Microscope (SEM) indicated that the body of LSC was porous.

关键词: sludge     foaming agents     ceramics     preheating process    

Fundamental influences of particles on stirred and unstirred venting processes of foaming systems

Henrik LEIMEISTER,Jörg STEINBACH

《化学科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 141-148 doi: 10.1007/s11705-014-1423-0

摘要: Venting is the common safety measure to protect plant equipment against excessive overpressure. So far, scenarios in which particles were part of the system and should have been accounted for did ignore their presence; the scenarios were treated like a two-phase system. Current research shows that particles can have a major influence on the venting behaviour. Experimental results indicate that particles affect level swell and relief flow especially of foamy systems. Based on those results four different layers of influence of the particle have been identified and are presented in a first model. Based on this model recommendations for the development of new and more complex models are given.

关键词: venting     multi-phase    

Evaluation of 1,4-naphthoquinone derivatives as antibacterial agents: activity and mechanistic studies

《环境科学与工程前沿(英文)》 2023年 第17卷 第3期 doi: 10.1007/s11783-023-1631-2

摘要:

● All 1,4-naphthoquinone hybrids exhibited significant antimicrobial activity.

关键词: 1     4-naphthoquinone derivatives     Antibacterial     Action mechanism     RecA    

Novel lysosome-targeted anticancer fluorescent agents used in zebrafish and nude mouse tumour imaging

《化学科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 112-120 doi: 10.1007/s11705-021-2075-5

摘要: The design of three novel fatty nitrogen mustard-based anticancer agents with fluorophores incorporated into the alkene structure (CXL 118, CXL121, and CXL122) is described in this report. The results indicated that these compounds are selectively located in lysosomes and exhibit effective antitumour activity. Notably, these compounds can directly serve as both reporting and imaging agents in vitro and in vivo without the need to add other fluorescent tagging agents.

关键词: fluorescent drug     lysosomal     anticancer     zebrafish     nude-mouse tumour imaging    

Comparison of masking agents for antimony speciation analysis using hydride generation atomic fluorescence

Jianhong XI,Mengchang HE,Kunpeng WANG,Guizhi ZHANG

《环境科学与工程前沿(英文)》 2015年 第9卷 第6期   页码 970-978 doi: 10.1007/s11783-014-0716-3

摘要: A sensitive atomic spectrometric method for the redox speciation analysis of Sb in water is described. The proposed method is based on the selective generation of stibine from Sb(III) in a continuous flow system using non-dispersive atomic fluorescence spectrometry for detection. The effects of the HCl concentration on the fluorescence intensities of Sb(III) and Sb(V) were investigated. The results indicated that atomic fluorescence emission due to Sb(V) can constructively interfere with the determination of Sb(III). For the determination of Sb(III), four compounds were tested as masking agents to inhibit the generation of stibine from Sb(V). The effects of the concentrations of the masking agents and of HCl on the fluorescence signals from Sb(III) and Sb(V) were studied. The results indicated that citric acid and NaF can successfully suppress hydride generation from Sb(V). To evaluate the developed methodology and the influence of the matrix, the recovery of Sb(III) from natural water that was spiked with different Sb(III) and Sb(V) concentrations was tested.

关键词: Sb(III)     Sb(V)     determination     masking agents     hydride generation (HG-AFS)    

Screening of textile finishing agents available on the Chinese market: An important source of per- and

Mehvish Mumtaz, Yixiang Bao, Wenchao Li, Lingxiao Kong, Jun Huang, Gang Yu

《环境科学与工程前沿(英文)》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1145-0

摘要: Kendrick mass defect was used for PFASs screening in textile finishing agents (TFAs). Total oxidizable precursor assay provides insight into unknown precursors. Perfluorooctane sulfonate was found as impurity in short ECF technology based TFAs. Perfluorooctanoate was also detected in C6 telomerization based TFAs. Long chain precursors were also observed in both types of TFAs. Organofluorinated surfactants are widely employed in textile finishing agents (TFAs) to achieve oil, water, and stain repellency. This has been regarded as an important emission source of per-and polyfluoroalkyl substances (PFASs) to the environment. China is the biggest manufacturer of clothes, and thus TFA production is also a relevant industrial activity. Nevertheless, to date, no survey has been conducted on PFAS contents in commercially available TFAs. In the present study, TFA products were investigated by the Kendrick mass defect method. The quantification results demonstrated a significant presence of perfluorooctane sulfonate (0.37 mg/L) in TFAs manufactured by electrochemical fluorination technology. The products obtained by short-chain PFAS-based telomerization were dominated by perfluorooctanoic acid (mean concentration: 0.29 mg/L), whose values exceeded the limits stated in the European Chemical Agency guidelines (0.025 mg/L). Moreover, the total oxidizable precursor assay indicated high levels of indirectly quantified precursors with long alkyl chains (C7–C9). Together, these results suggest that there is currently a certain of environmental and health risks in China that originates from the utilization of TFAs, and a better manufacturing processes are required to reduce such risks.

关键词: Textile finishing agents     Kendrick mass defect     Total oxidizable precursor assay    

Discovery of novel ursolic acid derivatives as effective antimicrobial agents through a ROS-mediated

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2101-2113 doi: 10.1007/s11705-023-2361-5

摘要: In response to the reduction of food production and economic losses caused by plant bacterial diseases, it is necessary to develop new, efficient, and green pesticides. Natural products are rich and sustainable source for the development of new pesticides due to their low toxicity, easy degradation, and eco-friendliness. In this study, we prepared three series of ursolic acid derivatives and assessed their antibacterial ability. Most target compounds exhibited outstanding antibacterial activities. Among them, the relative optimal EC50 values of Xanthomonas oryzae pv. oryzae and Xanthomonas axonopodis pv. citri were 2.23 (A17) and 1.39 (A16) μg·mL–1, respectively. The antimicrobial mechanism showed that compound A17 induced an excessive accumulation and production of reactive oxygen species in bacteria and damaged the cell membrane integrity to kill bacteria. More interestingly, the addition of low concentrations of exogenous hydrogen peroxide enhanced the antibacterial efficacy of compound A17 against Xanthomonas oryzae pv. oryzae. These entertaining results suggested that compound A17 induced an apparent apoptotic behavior in the tested bacteria. Overall, we developed the promising antimicrobial agents that destroyed the redox system of phytopathogenic bacteria, further demonstrating the unprecedented potential of ursolic acid for agricultural applications.

关键词: ursolic acid     antibacterial activities     reactive oxygen species     apoptosis    

Discovery of cryptolepine derivatives as novel promising agents against phytopathogenic bacteria

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 156-166 doi: 10.1007/s11705-022-2196-5

摘要: To ensure the production of food crops, a series of cryptolepine derivatives were synthesised, after which their antibacterial activities and mechanism of action against three plant pathogens were investigated. Our bioassay results indicated that most of the target compounds displayed potent inhibitory effects against Xanthomonas oryzae (X. oryzae) and Xanthomonas axonopodis pv. citri (X. axonopodis pv. c.). Remarkably, compound 9 exhibited the best in vitro antibacterial activity against X. oryzae, with a minimum inhibitory concentration (MIC) value of 0.78 μg·mL–1. Compound 2 exhibited the best in vitro antibacterial activity against X. axonopodis pv. c., with an MIC value of 0.39 μg·mL–1. These activities were superior to those of copper quinolate (MIC = 6.25, 25 μg·mL–1) and thiodiazole copper (MIC = 100, 200 μg·mL–1) against X. oryzae and X. axonopodis pv. c. In vivo experiments demonstrated the promising applicability of compound 9 for the control of rice bacterial infections. Furthermore, compound 9 was selected as a candidate to conduct preliminary analyses of the antibacterial mechanisms of cryptolepine derivatives. Scanning electron microscopy and transmission electron microscopy observations, extracellular polysaccharide production, biofilm formation, transcriptomic, quantitative reverse transcription-polymerase chain reaction analyses, and molecular docking assays were performed. Collectively, our findings demonstrated that compound 9 might act via multifarious mechanisms to down-regulate virulence factors and cause cell death.

关键词: cryptolepine derivatives     phytopathogenic bacteria     antibacterial activity     mechanism of action    

BIOINSECTICIDES AS FUTURE MAINSTREAM PEST CONTROL AGENTS: OPPORTUNITIES AND CHALLENGES

《农业科学与工程前沿(英文)》 2022年 第9卷 第1期   页码 82-97 doi: 10.15302/J-FASE-2021404

摘要:

Bioinsecticides are naturally-occurring substances from different sources that control insect pests. Ideal bioinsecticides should have low toxicity to non-target organisms. They should also be easily degraded in sewage treatment works and natural environments, highly effective in small quantities and affect target pests only. Public concerns about possible side-effects of synthetic pesticides have accelerated bioinsecticide research and development. However, to develop bioinsecticides into mainstream products, their high production costs, short shelf-life and often uncertain modes of action need to be considered. This review summarizes current progress on bioinsecticides which are categorized as biochemical insecticides and their derivatives, plant-incorporated protectants, and microbial bioinsecticides. The current constraints that prevent bioinsecticides from being widely used are discussed and future research directions are proposed.

 

关键词: biochemical insecticide / bioinsecticide / microbial bioinsecticides / plant-incorporated protectant / RNA insecticide    

Antimicrobial activity of topical agents against Propionibacterium acnes: an in vitro study of clinical

null

《医学前沿(英文)》 2016年 第10卷 第4期   页码 517-521 doi: 10.1007/s11684-016-0480-9

摘要:

This study aimed to compare the antimicrobial activities of topical agents against Propionibacterium acnes isolated from patients admitted to a hospital in Shanghai, China. The minimal inhibitory concentrations of the cultured P. acnes were determined in accordance with the Clinical and Laboratory Standards Institute. Susceptibilities to clindamycin and erythromycin were compared in terms of gender, age, disease duration, previous treatment, and disease severity. A total of 69 P. acnes strains were isolated from 98 patients (70.41%). The susceptibility to triple antibiotic ointment (neomycin/bacitracin/polymyxin B) and bacitracin was 100%. The susceptibility to fusidic acid was 92.7%. The resistance rates to neomycin sulfate, erythromycin, and clindamycin were 11.7%, 49.3%, and 33.4%, respectively. The high resistance rate to clindamycin and erythromycin was significantly affected by gender, previous treatment, and disease severity rather than by age and disease duration. Topical antibiotics should not be used separately for long-term therapy to avoid multiresistance. The use of topical antibiotics should be determined by clinicians on the basis of clinical conditions.

关键词: antimicrobial susceptibility/resistance     Propionibacterium acnes     topical antibiotics     in vitro study    

Triterpenoid inducers of Nrf2 signaling as potential therapeutic agents in sickle cell disease: a review

null

《医学前沿(英文)》 2015年 第9卷 第1期   页码 46-56 doi: 10.1007/s11684-015-0375-1

摘要:

Sickle cell disease (SCD) is an inherited disorder of hemoglobin in which the abnormal hemoglobin S polymerizes when deoxygenated. This polymerization of hemoglobin S not only results in hemolysis and vaso-occlusion but also precipitates inflammation, oxidative stress and chronic organ dysfunction. Oxidative stress is increasingly recognized as an important intermediate in these pathophysiological processes and is therefore an important target for therapeutic intervention. The transcription factor nuclear erythroid derived- 2 related factor 2 (Nrf2) controls the expression of anti-oxidant enzymes and is emerging as a protein whose function can be exploited with therapeutic intent. This review article is focused on triterpenoids that activate Nrf2, and their potential for reducing oxidative stress in SCD as an approach to prevent organ dysfunction associated with this disease. A brief overview of oxidative stress in the clinical context of SCD is accompanied by a discussion of several pathophysiological mechanisms contributing to oxidative stress. Finally, these mechanisms are then related to current management strategies in SCD that are either utilized currently or under evaluation. The article concludes with a perspective on the potential of the various therapeutic interventions to reduce oxidative stress and morbidity associated with SCD.

关键词: oxidative stress     Nrf2     triterpenoids     sickle cell disease     vaso-occlusion     CDDO-Me    

Self-etching adhesives: possible new pulp capping agents to vital pulp therapy

null

《医学前沿(英文)》 2011年 第5卷 第1期   页码 77-79 doi: 10.1007/s11684-010-0104-8

摘要:

Pulp capping is one of the solving for keeping vital pulp in the case of dentin caries, reversible pulpitis or traumatic pulp exposure. The presence of bacteria on the cavity walls or in the pulp was the major factor that leads to the failure of pulp capping. Traditional pulp capping agent, calcium hydroxide, may not prevent microleakage. Self-etching system is a newly developed adhesive system, which could provide less microleakage and would not break down or dissolve, preventing the oral fluids and bacteria from the pulp along the cavity wall. This may reduce such clinical problems as postoperative sensitivity, secondary caries and marginal discoloration. Researches showed that some kinds of self-etching adhesives induced the mild to moderate inflammatory pulp response, with negative bacterial staining. Inclusion of antibacterial components into self-etching system, such as 12- methacryloyloxydodecylpyridinium bromide (MDPB) may inhibit bacteria and provide better clinical effects. It is speculated that using the self-etching adhesive system containing the antibacterial agent, such as MDPB, to the dental pulp directly or indirectly, may inhibit bacteria after the placement of restoration as well as residual bacteria in the cavity.

关键词: dental pulp     pulp capping     self-etching adhesives     antibacterial components    

Effect of polyethylene glycol on the crystallization, rheology and foamability of poly(lactic acid) containing generated polyamide 6 nanofibrils

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2074-2087 doi: 10.1007/s11705-023-2342-8

摘要: In this study, the rheological properties, crystallization and foaming behavior of poly(lactic acid) with polyamide 6 nanofibrils were examined with polyethylene glycol as a compatibilizer. Polyamide 6 particles were deformed into nanofibrils during drawing. For the 10% polyamide 6 case, polyethylene glycol addition reduced the polyamide 6 fibril diameter from 365.53 to 254.63 nm, owing to the smaller polyamide 6 particle size and enhanced interface adhesion. Rheological experiments revealed that the viscosity and storage modulus of the composites were increased, which was associated with the three-dimensional entangled network of polyamide 6 nanofibrils. The presence of higher aspect ratio polyamide 6 nanofibrils substantially enhanced the melt strength of the composites. The isothermal crystallization kinetics results suggested that the polyamide 6 nanofibrils and polyethylene glycol had a synergistic effect on accelerating poly(lactic acid) crystallization. With the polyethylene glycol, the crystallization half-time reduced from 103.6 to 62.2 s. Batch foaming results indicated that owing to higher cell nucleation efficiency, the existence of polyamide 6 nanofibrils led to a higher cell density and lower expansion ratio. Furthermore, the poly(lactic acid)/polyamide 6 foams exhibited a higher cell density and expansion ratio than that of the foams without polyethylene glycol.

关键词: poly(lactic acid)     foaming     microfibrillation     rheological property     crystallization    

Polydimethylsiloxane assisted supercritical CO

Weixia Wang, Shuai Zhou, Zhong Xin, Yaoqi Shi, Shicheng Zhao

《化学科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 396-404 doi: 10.1007/s11705-016-1577-z

摘要: Foamable high melt strength polypropylene (HMSPP) was prepared by grafting styrene (St) onto polypropylene (PP) and simultaneously introducing polydimethylsiloxane (PDMS) through?a?one-step?melt extrusion process. The effect of PDMS viscosity on the foaming behavior of HMSPP was systematically investigated using supercritical CO as the foaming agent. The results show that the addition of PDMS has little effect on the grafting reaction of St and HMSPP exhibits enhanced elastic response and obvious strain hardening effect. Though the CO solubility of HMSPP with PDMS (PDMS-HMSPP) is lower than that of HMSPP without PDMS, especially for PDMS with low viscosity, the PDMS-HMSPP foams exhibit narrow cell size distribution and high cell density. The fracture morphology of PDMS-HMSPP shows that PDMS with low viscosity disperses more easily and uniformly in HMSPP matrix, leading to form small domains during the extrusion process. These small domains act as bubble nucleation sites and thus may be responsible for the improved foaming performance of HMSPP.

关键词: high melt strength polypropylene (HMSPP)     polydimethylsiloxane (PDMS)     supercritical CO2     foaming behavior    

Etiology of invasive candidosis agents in Russia: a multicenter epidemiological survey

null

《医学前沿(英文)》 2018年 第12卷 第1期   页码 84-91 doi: 10.1007/s11684-017-0612-x

摘要:

A multicenter prospective epidemiological survey on the etiologic agents of invasive candidosis was conducted in Russia in the period of 2012–2014. Samples were collected from 284 patients with invasive candidosis and Candida species isolated by culture. The species were identified by DNA sequencing and MALDI-TOF mass-spectrometry. A total of 322 isolates were recovered, in which 96% of Сandida species belonged to six major species, namely, C. albicans (43.2%), C. parapsilosis (20.2%), C. glabrata (11.5%), C. tropicalis (9.6%), C. krusei (6.2%), and C. guilliermondii (5.3%). Most Candida species were isolated from blood samples (83.23%). Notably, the prevalence rate of C. albicans reduced from 52.38% to 32.79% (2012 vs. 2014) (P=0.01) whereas that of non-C. albicans increased from 47.62% (2012) to 67.21% (2014) (P<0.01). Species distribution differed among geographical regions; specifically, the prevalence rate of C. albicans as an etiologic agent of invasive candidosis in Siberian Federal region was significantly higher than that in other Federal regions. Results indicated a shift from C. albicans to non-C. albicans. Therefore, a detailed investigation on the contributing factors and appropriate treatment of invasive candidosis is needed.

关键词: prevalence     &Scy     andida species     invasive candidosis     nosocomial     etiology     MALDI-TOF mass-spectrometry     candidemia    

标题 作者 时间 类型 操作

Properties and effect of forming sewage sludge into lightweight ceramics

Min YUE, Qinyan YUE, Yuanfeng QI, Baoyu GAO, Hui YU

期刊论文

Fundamental influences of particles on stirred and unstirred venting processes of foaming systems

Henrik LEIMEISTER,Jörg STEINBACH

期刊论文

Evaluation of 1,4-naphthoquinone derivatives as antibacterial agents: activity and mechanistic studies

期刊论文

Novel lysosome-targeted anticancer fluorescent agents used in zebrafish and nude mouse tumour imaging

期刊论文

Comparison of masking agents for antimony speciation analysis using hydride generation atomic fluorescence

Jianhong XI,Mengchang HE,Kunpeng WANG,Guizhi ZHANG

期刊论文

Screening of textile finishing agents available on the Chinese market: An important source of per- and

Mehvish Mumtaz, Yixiang Bao, Wenchao Li, Lingxiao Kong, Jun Huang, Gang Yu

期刊论文

Discovery of novel ursolic acid derivatives as effective antimicrobial agents through a ROS-mediated

期刊论文

Discovery of cryptolepine derivatives as novel promising agents against phytopathogenic bacteria

期刊论文

BIOINSECTICIDES AS FUTURE MAINSTREAM PEST CONTROL AGENTS: OPPORTUNITIES AND CHALLENGES

期刊论文

Antimicrobial activity of topical agents against Propionibacterium acnes: an in vitro study of clinical

null

期刊论文

Triterpenoid inducers of Nrf2 signaling as potential therapeutic agents in sickle cell disease: a review

null

期刊论文

Self-etching adhesives: possible new pulp capping agents to vital pulp therapy

null

期刊论文

Effect of polyethylene glycol on the crystallization, rheology and foamability of poly(lactic acid) containing generated polyamide 6 nanofibrils

期刊论文

Polydimethylsiloxane assisted supercritical CO

Weixia Wang, Shuai Zhou, Zhong Xin, Yaoqi Shi, Shicheng Zhao

期刊论文

Etiology of invasive candidosis agents in Russia: a multicenter epidemiological survey

null

期刊论文