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1.
Environ Res ; 211: 113075, 2022 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-35271831

RESUMO

Synthetic antibiotics have been known for years to combat bacterial antibiotics. But their overuse and resistance have become a concern recently. The antibiotics reach the environment, including soil from the manufacturing process and undigested excretion by cattle and humans. It leads to overburden and contamination of the environment. These organic antibiotics remain in the environment for a very long period. During this period, antibiotics come in contact with various flora and fauna. The ill manufacturing practices and inadequate wastewater treatment cause a severe problem to the water bodies. After pretreatment from pharmaceutical industries, the effluents are released to the water bodies such as rivers. Even after pretreatment, effluents contain a significant number of antibiotic residues, which affect the living organisms living in the water bodies. Ultimately, river contaminated water reaches the ocean, spreading the contamination to a vast environment. This review paper discusses the impact of synthetic organic contamination on the environment and its hazardous effect on health. In addition, it analyzes and suggests the biotechnological strategies to tackle organic antibiotic residue proliferation. Moreover, the degradation of organic antibiotic residues by biocatalyst and biochar is analyzed. The circular economy approach for waste-to-resource technology for organic antibiotic residue in China is analyzed for a sustainable solution. Overall, the significant challenges related to synthetic antibiotic residues and future aspects are analyzed in this review paper.

2.
Angew Chem Int Ed Engl ; 61(9): e202116208, 2022 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-34964224

RESUMO

Polyhydroxyalkanoates (PHAs) are a unique class of commercially manufactured biodegradable polyesters with properties suitable for partially substituting petroleum-based plastics. However, high costs and low volumes of production have restricted their application as commodity materials. In this study, tri-metallic complexes were developed for carbonylative polymerization via a dual catalysis strategy, and 17 products of novel PHAs with up to 38.2 kg mol-1 Mn values were discovered. The polymerization proceeds in a sequential fashion, which entails the carbonylative ring expansion of epoxide to ß-lactone and its subsequent ring-opening polymerization that occurs selectively at the O-alkyl bond via carboxylate species. The wide availability and structural diversity of epoxide monomers provide PHAs with various structures, excellent functionalities, and tunable properties. This study represents a rare example of the preparation of PHAs using epoxides and carbon monoxide as raw materials.


Assuntos
Complexos de Coordenação/química , Compostos de Epóxi/química , Poli-Hidroxialcanoatos/síntese química , Catálise , Estrutura Molecular , Poli-Hidroxialcanoatos/química , Polimerização
3.
Theranostics ; 9(23): 6745-6763, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31660066

RESUMO

RATIONALE: Inducing cancer differentiation is a promising approach to treat cancer. Here, we identified chlorogenic acid (CA), a potential differentiation inducer, for cancer therapy, and elucidated the molecular mechanisms underlying its differentiation-inducing effects on cancer cells. METHODS: Cancer cell differentiation was investigated by measuring malignant behavior, including growth rate, invasion/migration, morphological change, maturation, and ATP production. Gene expression was analyzed by microarray analysis, qRT-PCR, and protein measurement, and molecular biology techniques were employed for mechanistic studies. LC/MS analysis was the method of choice for chemical detection. Finally, the anticancer effect of CA was evaluated both in vitro and in vivo. Results: Cancer cells treated with CA showed reduced proliferation rate, migration/invasion ability, and mitochondrial ATP production. Treating cancer cells with CA resulted in elevated SUMO1 expression through acting on its 3'UTR and stabilizing the mRNA. The increased SUMO1 caused c-Myc sumoylation, miR-17 family downregulation, and p21 upregulation leading to G0/G1 arrest and maturation phenotype. CA altered the expression of differentiation-related genes in cancer cells but not in normal cells. It inhibited hepatoma and lung cancer growth in tumor-bearing mice and prevented new tumor development in naïve mice. In glioma cells, CA increased expression of specific differentiation biomarkers Tuj1 and GFAP inducing differentiation and reducing sphere formation. The therapeutic efficacy of CA in glioma cells was comparable to that of temozolomide. CA was detectable both in the blood and brain when administered intraperitoneally in animals. Most importantly, CA was safe even at very high doses. CONCLUSION: CA might be a safe and effective differentiation-inducer for cancer therapy. "Educating" cancer cells to differentiate, rather than killing them, could be a novel therapeutic strategy for cancer.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Diferenciação Celular/efeitos dos fármacos , Ácido Clorogênico/farmacologia , Glioma/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Células A549 , Trifosfato de Adenosina/metabolismo , Animais , Antineoplásicos/uso terapêutico , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos dos fármacos , Ácido Clorogênico/uso terapêutico , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Pontos de Checagem da Fase G1 do Ciclo Celular , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos NOD , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Ratos , Ratos Wistar , Proteína SUMO-1/metabolismo
4.
Ecol Evol ; 9(16): 9376-9384, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31463028

RESUMO

Allochthonous (e.g., riparian) plant litter is among the organic matter resources that are important for wetland ecosystems. A compact canopy of free-floating vegetation on the water surface may allow for riparian litter to remain on it for a period of time before sinking to the bottom. Thus, we hypothesized that canopy of free-floating vegetation may slow decomposition processes in wetlands. To test the hypothesis that the retention of riparian leaf litter on the free-floating vegetation in wetlands affects their subsequent decomposition on the bottom of wetlands, a 50-day in situ decomposition experiment was performed in a wetland pond in subtropical China, in which litter bags of single species with fine (0.5 mm) or coarse (2.0 mm) mesh sizes were placed on free-floating vegetation (dominated by Eichhornia crassipes, Lemna minor, and Salvinia molesta) for 25 days and then moved to the pond bottom for another 25 days or remained on the pond bottom for 50 days. The leaf litter was collected from three riparian species, that is, Cinnamomum camphora, Diospyros kaki, and Phyllostachys propinqua. The retention of riparian leaf litter on free-floating vegetation had significant negative effect on the carbon loss, marginal negative effects on the mass loss, and no effect on the nitrogen loss from leaf litter, partially supporting the hypothesis. Similarly, the mass and carbon losses from leaf litter decomposing on the pond bottom for the first 25 days of the experiment were greater than those from the litter decomposing on free-floating vegetation. Our results highlight that in wetlands, free-floating vegetation could play a vital role in litter decomposition, which is linked to the regulation of nutrient cycling in ecosystems.

5.
Bioorg Chem ; 87: 136-141, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30884307

RESUMO

Chlorovaltrates U-W (1-3), three previously undescribed iridoids, together with four known analogues were isolated from the roots of Valeriana jatamansi. Their structures were elucidated by means of spectroscopic analyses (HRESIMS, NMR). The cytotoxicity of all isolates was evaluated. Compounds 5-7 exhibited selective cytotoxicity against HCT116 cells, with IC50 values of 9.3, 1.7 and 2.2 µM, respectively. The preliminary mechanistic study revealed that, the cytotoxicity effect of 6 was attributed to Akt/mTOR activation blockade via inhibition of PDK1 phosphorylation. Meanwhile, compound 6 could induce autophagosome formation in HCT116 cells via suppressing its downstream Akt/mTOR. These findings show that compound 6 could be of great importance to the development of anti-colon cancer agents.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Autofagia/efeitos dos fármacos , Iridoides/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Valeriana/química , Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/química , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Humanos , Iridoides/química , Iridoides/isolamento & purificação , Modelos Moleculares , Estrutura Molecular , Raízes de Plantas/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piruvato Desidrogenase Quinase de Transferência de Acetil/antagonistas & inibidores , Piruvato Desidrogenase Quinase de Transferência de Acetil/metabolismo , Relação Estrutura-Atividade , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo
6.
Environ Sci Pollut Res Int ; 26(8): 8248-8256, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30701469

RESUMO

In wetland ecosystems, vegetation can float freely on water surface, forming dense canopy which may play important ecological roles. This is especially true in many urban wetlands in which fluidity is low and nutrient level is high. So far, effects of free-floating vegetation on abiotic and biotic factors of wetlands have been known, while little on wetland ecosystem functions such as litter decomposition. To examine whether the canopy of free-floating vegetation on water surface will influence litter decomposition in wetlands or not, we conducted a 50-day in situ decomposition experiment in a subtropical urban pond wetland, in which litter bags of nine combinations of three mesh sizes and three litter species were put on the bottoms of total 22 ponds which were half with and half without free-floating vegetation canopy on the water surface. The ponds with and without the canopy had different water physicochemical properties. Overall, the canopy, the species identity, and the mesh size significantly decelerated mass loss and carbon loss of leaf litters while slightly on nitrogen loss. Effects of the canopy on leaf litter decomposition also showed species- and mesh size-dependent. Our results suggest that free-floating vegetation on water surface can alter water environmental factors and consequently change ecosystem functioning in wetlands.


Assuntos
Folhas de Planta/fisiologia , Áreas Alagadas , Biodegradação Ambiental , Carbono/metabolismo , China , Ecossistema , Nitrogênio/metabolismo , Plantas , Lagoas
7.
Chronic Dis Transl Med ; 5(3): 178-187, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31891129

RESUMO

Colorectal cancer (CRC) is a common malignant tumor that affects people worldwide. Metagenomic analyses have shown an enrichment of Fusobacterium nucleatum (F. nucleatum) in colorectal carcinoma tissue; many studies have indicated that F. nucleatum is closely related to the colorectal carcinogenesis. In this review, we provide the latest information to reveal the related molecular mechanisms. The known virulence factors of F. nucleatum promote adhesion to intestinal epithelial cells via FadA and Fap2. Besides, Fap2 also binds to immune cells causing immunosuppression. Furthermore, F. nucleatum recruits tumor-infiltrating immune cells, thus yielding a pro-inflammatory microenvironment, which promotes colorectal neoplasia progression. F. nucleatum was also found to potentiate CRC development through toll-like receptor 2 (TLR2)/toll-like receptor 4 (TLR4) signaling and microRNA (miRNA)-21 expression. In addition, F. nucleatum increases CRC recurrence along with chemoresistance by mediating a molecular network of miRNA-18a*, miRNA-4802, and autophagy components. Moreover, viable F. nucleatum was detected in mouse xenografts of human primary colorectal adenocarcinomas through successive passages. These findings indicated that an increased number of F. nucleatum in the tissues is a biomarker for the diagnosis and prognosis of CRC, and the underlying molecular mechanism can probably provide a potential intervention treatment strategy for patients with F. nucleatum-associated CRC.

8.
Zhongguo Zhong Yao Za Zhi ; 43(22): 4450-4456, 2018 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-30593237

RESUMO

As one of the three pillars of Chinese medicine industry, traditional Chinese medicines prepared in ready-to-use forms are important raw materials for clinical medication and production of Chinese patent drugs. By considering the literature of Curcumae Radix, a multi-source Chinese herb and the situation of market investigation, the modern evaluation method based on traditional grading was introduced for comprehensive evaluation of the processed Curcumae Radix. The correlation between traditional grading method and modern evaluation index was explored to establish the grading standard of Curcumae Radix. According to the comprehensive evaluation, Curcumae Radix was divided into four grades: superior, first, second and third grades under the guidance of the theory of traditional Chinese medicine. This study provides a new idea for the grading of multi-source processed Chinese medicine, achieving high quality and good price, which is helpful to improve the clinical efficacy.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Raízes de Plantas
9.
Sci Rep ; 7: 43018, 2017 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-28233774

RESUMO

Geographic patterns in leaf stoichiometry reflect plant adaptations to environments. Leaf stoichiometry variations along environmental gradients have been extensively studied among terrestrial plants, but little has been known about intraspecific leaf stoichiometry, especially for wetland plants. Here we analyzed the dataset of leaf N and P of a cosmopolitan wetland species, Phragmites australis, and environmental (geographic, climate and soil) variables from literature and field investigation in natural wetlands distributed in three climatic regions (subtropical, temperate and highland) across China. We found no clear geographic patterns in leaf nutrients of P. australis across China, except for leaf N:P ratio increasing with altitude. Leaf N and N:P decreased with mean annual temperature (MAT), and leaf N and P were closely related to soil pH, C:N ratio and available P. Redundancy analysis showed that climate and soil variables explained 62.1% of total variation in leaf N, P and N:P. Furthermore, leaf N in temperate region and leaf P in subtropical region increased with soil available P, while leaf N:P in subtropical region decreased with soil pH. These patterns in P. australis different from terrestrial plants might imply that changes in climate and soil properties can exert divergent effects on wetland and terrestrial ecosystems.

10.
J Org Chem ; 81(19): 8959-8966, 2016 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-27627648

RESUMO

Carbon dioxide has attracted broad interest as a renewable C1 feedstock for efficient transformation into value-added organic chemicals; nevertheless, far less attention was paid to its stereochemically controlled catalytic fixation/conversion processes. Here, we report a new strategy for the selective synthesis of chiral carbamates from carbon dioxide via polycarbonate intermediates, which are formed by the desymmetric copolymerization of meso-epoxides using enantiopure dinuclear Co(III) catalyst systems with 99% enantioselectivity. Subsequent degradation reaction of the resultant polycarbonates with various primary or secondary amine nucleophiles can afford optically active carbamates, with the complete configuration retention of the two chiral carbon centers. Our accomplishment reported here opens up a new route to prepare a wide range of CO2-based carbamate scaffolds with excellent yields and 99% enantiomeric excess.

11.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 44(5): 571-7, 2015 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-26713534

RESUMO

OBJECTIVE: To detect the expression of the plateau adaptablity gene(EPAS1, EGLN1 and PPARα) and proteins(HIF-2, PHD2 and PPARα) in rats blood, heart, liver, lung and kidney tissue after the rats exposed to high altitude. METHODS: The Wistar rats were randomly divided into plain group(Shanghai, 55 m), acute exposure to high altitude 3400 m group, acute exposure to high altitude 4300 m group. Blood and organs of rats were collected in 1, 3, 5 days after arrival. Real time PCR and ELISA were used to compare the expression of plateau adaptablity gene and related protein between plain group and high altitude exposure groups. RESULTS: The count of red blood cells, hemoglobin and HCT in high altitude 4300 m were higher than those in plain group. Compared with plain group, the expression of EPAS1 gene in blood, heart, liver and kidney tissue of rats at high altitude increased obviously(all P<0.05); the expression of EGLN1 in the heart, liver, brain and kidney increased, and PPARα gene in the heart, liver and kidney increased(all P<0.05). Compared with plain group, the expression of HIF-2 protein increased significantly at high altitudes in the liver, brain and kidney tissues. PHD2 and PPARα increased in the heart, liver and kidney. CONCLUSION: Plateau adaptive genes(EPAS1, EGLN1 and PPARα) and protein(HIF-2, PHD2 and PPARα) differed in different altitude and different organizations. They might be used as target markers of plateau hypoxia.


Assuntos
Adaptação Fisiológica , Altitude , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Animais , Encéfalo , China , Coração , Hipóxia , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Rim , Fígado , Pulmão , PPAR alfa/metabolismo , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Ratos , Ratos Wistar
12.
Front Plant Sci ; 6: 901, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26579151

RESUMO

Leaf economics spectrum (LES), characterizing covariation among a suite of leaf traits relevant to carbon and nutrient economics, has been examined largely among species but hardly within species. In addition, very little attempt has been made to examine whether the existence of LES depends on spatial scales. To address these questions, we quantified the variation and covariation of four leaf economic traits (specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus contents) in a cosmopolitan wetland species (Phragmites australis) at three spatial (inter-regional, regional, and site) scales across most of the species range in China. The species expressed large intraspecific variation in the leaf economic traits at all of the three spatial scales. It also showed strong covariation among the four leaf economic traits across the species range. The coordination among leaf economic traits resulted in LES at all three scales and the environmental variables determining variation in leaf economic traits were different among the spatial scales. Our results provide novel evidence for within-species LES at multiple spatial scales, indicating that resource trade-off could also constrain intraspecific trait variation mainly driven by climatic and/or edaphic differences.

13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(5): 1392-7, 2015 May.
Artigo em Chinês | MEDLINE | ID: mdl-26415466

RESUMO

Cu in navel orange was detected rapidly by laser-induced breakdown spectroscopy (LIBS) combined with partial least squares (PLS) for quantitative analysis, then the effect on the detection accuracy of the model with different spectral data ptetreatment methods was explored. Spectral data for the 52 Gannan navel orange samples were pretreated by different data smoothing, mean centralized and standard normal variable transform. Then 319~338 nm wavelength section containing characteristic spectral lines of Cu was selected to build PLS models, the main evaluation indexes of models such as regression coefficient (r), root mean square error of cross validation (RMSECV) and the root mean square error of prediction (RMSEP) were compared and analyzed. Three indicators of PLS model after 13 points smoothing and processing of the mean center were found reaching 0. 992 8, 3. 43 and 3. 4 respectively, the average relative error of prediction model is only 5. 55%, and in one word, the quality of calibration and prediction of this model are the best results. The results show that selecting the appropriate data pre-processing method, the prediction accuracy of PLS quantitative model of fruits and vegetables detected by LIBS can be improved effectively, providing a new method for fast and accurate detection of fruits and vegetables by LIBS.


Assuntos
Citrus sinensis/química , Cobre/análise , Frutas/química , Análise Espectral , Lasers , Análise dos Mínimos Quadrados , Modelos Teóricos
14.
World J Gastroenterol ; 21(21): 6543-9, 2015 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-26074692

RESUMO

AIM: To investigate the effect of repeated lower +Gz exposure on liver injury induced by high +Gz exposure in rats. METHODS: Sixty male Wister rats were randomly divided into a blank control group, a low G preconditioning group (LG) (exposed to +4 Gz/5 min per day for 3 d before +10 Gz/5 min exposure), and a +10 Gz/5 min group (10G) (n = 20 in each group). Blood specimens and liver tissue were harvested at 0 h and 6 h after +10 Gz/5 min exposure. Liver function was analyzed by measuring serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels, and liver injury was further assessed by histopathological observation. Malondialdehyde (MDA), superoxide dismutase (SOD) and Na(+)-K(+)-ATPase were determined in hepatic tissue. RESULTS: The group LG had lower ALT, AST, and MDA values at 0 h after exposure than those in group 10G. SOD values and Na(+)-K(+)-ATPase activity in the LG group were higher than in group 10G 0 h post-exposure. Hepatocyte injury was significantly less in group LG than in group 10G on histopathological evaluation. CONCLUSION: It is suggested that repeated low +Gz exposure shows a protective effect on liver injury induced by high +Gz exposure in rats.


Assuntos
Gravidade Alterada , Hipergravidade , Hipogravidade , Fígado/lesões , Ferimentos e Lesões/prevenção & controle , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Biomarcadores/sangue , Centrifugação , Citoproteção , Modelos Animais de Doenças , Fígado/metabolismo , Fígado/patologia , Testes de Função Hepática , Masculino , Malondialdeído/metabolismo , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Tempo , Ferimentos e Lesões/sangue , Ferimentos e Lesões/etiologia , Ferimentos e Lesões/patologia
15.
Environ Sci Pollut Res Int ; 22(13): 9575-88, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25940469

RESUMO

Nitrate (NO3(-)) contamination of freshwater is considered one of the most prevalent global environmental problems. Dual stable isotopic compositions (δ(15)N and δ(18)O) of NO3(-) can provide helpful information and have been well documented as being a powerful tool to track the source of NO3(-) in freshwater ecosystems. The ion-exchange method is a reliable and precise technique for measuring the δ(15)N and δ(18)O of NO3(-) and has been widely employed to collect NO3(-) from freshwater ecosystems. This review summarizes and presents the principles, affecting factors and corresponding significant improvements of the ion-exchange method. Finally, potential improvements and perspectives for the applicability of this method are also discussed, as are suggestions for further research and development drawn from the overall conclusions.


Assuntos
Monitoramento Ambiental/métodos , Água Doce/química , Nitratos/análise , Poluentes Químicos da Água/análise , Ecossistema , Troca Iônica , Isótopos , Nitrogênio , Isótopos de Nitrogênio/análise , Óxidos de Nitrogênio , Oxigênio , Isótopos de Oxigênio/análise
16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(7): 2021-4, 2015 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-26717771

RESUMO

Heavy metals pollution in foodstuffs is more and more serious. It is impossible to satisfy the modern agricultural development by conventional chemical analysis. Laser induced breakdown spectroscopy (LIBS) is an emerging technology with the characteristic of rapid and nondestructive detection. But LIBS' s repeatability, sensitivity and accuracy has much room to improve. In this work, heavy metal Cu in Gannan Navel Orange which is the Jiangxi specialty fruit will be predicted by LIBS. Firstly, the navel orange samples were contaminated in our lab. The spectra of samples were collected by irradiating the peel by optimized LIBS parameters. The laser energy was set as 20 mJ, delay time of Spectral Data Gathering was set as 1.2 micros, the integration time of Spectral data gathering was set as 2 ms. The real concentration in samples was obtained by AAS (atom absorption spectroscopy). The characteristic variables Cu I 324.7 and Cu I 327.4 were extracted. And the calibration model was constructed between LIBS spectra and real concentration about Cu. The results show that relative error of the predicted concentrations of three relational model were 7.01% or less, reached a minimum of 0.02%, 0.01% and 0.02% respectively. The average relative errors were 2.33%, 3.10% and 26.3%. Tests showed that different characteristic variables decided different accuracy. It is very important to choose suitable characteristic variable. At the same time, this work is helpful to explore the distribution of heavy metals between pulp and peel.


Assuntos
Citrus sinensis/química , Cobre/análise , Contaminação de Alimentos/análise , Frutas/química , Calibragem , Lasers , Espectrofotometria Atômica
17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(7): 1954-8, 2014 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-25269315

RESUMO

The purpose of this research is to study the influence of double pulse laser induced breakdown spectroscopy (DP-LIBS) on the sensitivity of Cu in water. The water solution of Cu was tested by collinear DP-LIBS in this article. The results show that spectral intensity of Cu can be enhanced obviously by DP-LIBS, compared with single pulse laser induced breakdown spectroscopy (SP-LIBS). Besides, the experimental results were significantly impacted by delay time between laser pulse and spectrometer acquisition, delay time of double laser pulse and energy of laser pulse and so on. The paper determined the best conditions for DP-LIBS detecting Cu in water. The optimal acquisition delay time was 1 380 ns. The best laser pulse delay time was 25 ns. The most appropriate energy of double laser pulse was 100 mJ. Characteristic analysis of spectra of Cu at 324.7 and 327.4 nm was done for quantitative analysis. The detection limit was 3.5 microg x mL(-1) at 324.7 nm, and the detection limit was 4.84 microg x mL(-1) at 327.4 nm. The relative standard deviation of the two characteristic spectral lines was within 10%. The calibration curve of characteristic spectral line, established by 327.4 nm, was verified with 500 microg x mL(-1) sample. Concentration of the sample was 446 microg x mL(-1) calculated by the calibration curve. This research shows that the detection sensitivity of Cu in water can be improved by DP-LIBS. At the same time, it had high stability.

18.
Biomed Res Int ; 2014: 167197, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24779006

RESUMO

The aim of the study was to investigate the impact of municipal solid waste incinerator (MSWI) bottom ash (BA) codisposed with municipal solid waste (MSW) on landfill stabilization according to the leachate quality in terms of organic matter and nitrogen contents. Six simulated landfills, that is, three conventional and three recirculated, were employed with different ratios of MSWI BA to MSW. The results depicted that, after 275-day operation, the ratio of MSWI BA to fresh refuse of 1 : 10 (V : V) in the landfill was still not enough to provide sufficient acid-neutralizing capacity for a high organic matter composition of MSW over 45.5% (w/w), while the ratio of MSWI BA to fresh refuse of 1 : 5 (V : V) could act on it. Among the six experimental landfills, leachate quality only was improved in the landfill operated with the BA addition (the ratio of MSWI BA to fresh refuse of 1 : 5 (V : V)) and leachate recirculation.


Assuntos
Biodegradação Ambiental , Cinza de Carvão/química , Eliminação de Resíduos/métodos , Resíduos Sólidos , Instalações de Eliminação de Resíduos , Ácidos/química , Incineração/métodos
20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 33(11): 3120-3, 2013 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-24555394

RESUMO

The present study is to improve the sensitivity of detection and reduce the limit of detection in detecting heavy metal of soil by laser induced breakdown spectroscopy (LIBS). The Cr element of national standard soil was regarded as the research object. In the experiment, a conical cavity with small diameter end of 20 mm and large diameter end of 45 mm respectively was installed below the focusing lens near the experiment sample to mainly confine the signal transmitted by plasma and to some extent to confine the plasma itself in the LIBS setup. In detecting Cr I 425.44 nm, the beast delay time gained from experiment is 1.3 micros, and the relative standard deviation is below 10%. Compared with the setup of non-spatial confinement, the spectral intensity of Cr in the soil sample was enhanced more than 7%. Calibration curve was established in the Cr concentration range from 60 to 400 microg x g(-1). Under the condition of spatial confinement, the liner regression coefficient and the limit of detection were 0.997 71 and 18.85 microg x g(-1) respectively, however, the regression coefficient and the limit of detection were 0.991 22 and 36.99 microg x g(-1) without spatial confinement. So, this shows that conical spatial confinement can/improve the sensitivity of detection and enhance the spectral intensity. And it is a good auxiliary function in detecting Cr in the soil by laser induced breakdown spectroscopy.

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