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1.
Redox Biol ; 26: 101295, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31421410

RESUMO

Hypertension is one of the major predisposing factors for neurodegenerative disease characterized with activated renin-angiotensin system (RAS) in both periphery and brain. Vitamin D (VitD) is recently recognized as a pleiotropic hormone with strong neuroprotective properties. While multiple lines of evidence suggest that VitD can act on RAS, the evidence concerning the crosstalk between VitD and RAS in the brain is limited. Therefore, this study aims to evaluate whether VitD can modulate brain RAS to trigger neuroprotective actions in the brain of spontaneously hypertensive rats (SHR). Our data showed that calcitriol treatment induced VDR expression and inhibited neural death in the prefrontal cortex of SHR. Sustained calcitriol administration also inhibited microglia M1 polarization, but enhanced M2 polarization, accompanied with decreased expression of proinflammatory cytokines. We then further explored the potential mechanisms and showed that SHR exhibited overactivated classical RAS with increased expression of angiotensin II (Ang II) receptor type 1 (AT1), angiotensin converting enzyme (ACE) and Ang II production, whereas the counteracting arm of traditional RAS, ACE2/Ang(1-7)/MasR, was impaired in the SHR brain. Calcitriol nonsignificantly suppressed AT1 and ACE but markedly reduced Ang II formation. Intriguingly, calcitriol exerted pronouncedly impact on ACE2/Ang(1-7)/MasR axis with enhanced expression of ACE2, MasR and Ang(1-7) generation. Meanwhile, calcitriol ameliorated the overactivation of NADPH-oxidase (Nox), the downstream of RAS, in SHR, and also mitigated oxidative stress. In microglial (BV2) cells, we further found that calcitriol induced ACE2 and MasR with no significant impact on ACE and AT1. In accordance, calcitriol also attenuated Ang II-induced Nox activation and ROS production, and shifted the microglia polarization from M1 to M2 phenotype. However, co-treatment with A779, a specific MasR antagonist, abrogated the antioxidant and neuroimmune modulating actions of VitD. These findings strongly indicate the involvement of ACE2/Ang(1-7)/MasR pathway in the neuroprotective mechanisms of VitD in the hypertensive brain.

2.
Medicine (Baltimore) ; 98(28): e16301, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31305415

RESUMO

BACKGROUND: Knee osteoarthritis (KOA), known as severe degenerative arthritis, commonly occurs in middle-aged and elderly people all over the world. Acupuncture as traditional oriental intervention is getting widely used and several systematic reviews (SRs) have reported the effectiveness of acupuncture on pain relief and functional recovery in patients with KOA. OBJECTIVE: Conducting an overview of SRs to provide more reliable evidence-based medical references for clinical practitioners and researchers of the effectiveness and safety of acupuncture for KOA. DATA SOURCES: EMBASE, Medline, Web of science, the Cochrane library, China National Knowledge Infrastructure, the Chinese Science and Technology Periodical Database, China Biology Medicine, Wan Fang Digital Journals, and PROSPERO databases from inception to December 2018, magazines, websites, and unpublished sources. SELECTION CRITERIA: Potential SRs were independently selected by 2 reviewers following a predetermined protocol. DATA EXTRACTION: Data information of included SRs were independently extracted by 2 reviewers following a predetermined standardized data extraction form. REVIEW APPRAISAL: The risk of bias and reporting quality of included SRs were evaluated by the Risk of Bias in Systematic reviews (ROBIS) tool and the Preferred Reporting Item for Systematic Review and Meta-analysis (PRISMA) statement. The quality of evidence of outcomes was evaluated by the Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: A total of 12 SRs were included. All the SRs were published in recent 12 years, ranging from 2006 to 2017. According to ROBIS, 4 SRs were in low risk in domain 1 and 7 in domain 3 of phase 2, and 2 SRs were low risk in phase 3. Among 27 items of PRISMA, 19 items were reported over 70% of compliance. Using GRADE assessment, of 34 outcomes, high quality of evidence was found in 5 outcomes, 17 outcomes were rated moderate quality, and 11 outcomes were low quality. According to high-quality outcomes, acupuncture had more total effective rate, short-term effective rate, and less adverse reactions than western medicine in treating KOA. In terms of Lequesne index and Lysholm knee score scale score, the effectiveness of electroacupuncture was better than that of western medicine. LIMITATIONS: There might be missing information. There may be duplicated clinical trials included by each SR that might have impact on the synthetic findings. CONCLUSIONS: According to the high-quality evidence, we concluded that acupuncture may have some advantages in treating KOA. However, there are some risk of bias and reporting deficiencies still needed to be improved.


Assuntos
Terapia por Acupuntura , Osteoartrite do Joelho/terapia , Terapia por Acupuntura/efeitos adversos , Artralgia/etiologia , Artralgia/terapia , Humanos , Osteoartrite do Joelho/complicações , Segurança do Paciente , Revisão Sistemática como Assunto
3.
J Environ Sci (China) ; 83: 64-72, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221388

RESUMO

To evaluate the potential benefits of biomass use for air pollution control, this paper identified and quantified the emissions of major reactive organic compounds anticipated from biomass-fired industrial boilers. Wood pellets (WP) and straw pellets (SP) were burned to determine the volatile organic compound emission profiles for each biomass-boiler combination. More than 100 types of volatile organic compounds (VOCs) were measured from the two biomass boilers. The measured VOC species included alkanes, alkenes and acetylenes, aromatics, halocarbons and carbonyls. A single coal-fired boiler (CB) was also studied to provide a basis for comparison. Biomass boiler 1 (BB1) emitted relatively high proportions of alkanes (28.9%-38.1% by mass) and alkenes and acetylenes (23.4%-40.8%), while biomass boiler 2 (BB2) emitted relatively high proportions of aromatics (27.9%-29.2%) and oxygenated VOCs (33.0%-44.8%). The total VOC (TVOC) emission factors from BB1 (128.59-146.16 mg/kg) were higher than those from BB2 (41.26-85.29 mg/kg). The total ozone formation potential (OFP) ranged from 6.26 to 81.75 mg/m3 with an average of 33.66 mg/m3 for the two biomass boilers. The total secondary organic aerosol potential (SOAP) ranged from 61.56 to 211.67 mg/m3 with an average of 142.27 mg/m3 for the two biomass boilers. The emission factors (EFs) of TVOCs from biomass boilers in this study were similar to those for industrial coal-fired boilers with the same thermal power. These data can supplement existing VOC emission factors for biomass combustion and thus enrich the VOC emission inventory.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Ozônio/análise , Compostos Orgânicos Voláteis/análise , China , Incineração , Indústrias
4.
Sci Total Environ ; 676: 436-446, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31048173

RESUMO

In order to analyze the temporal-spatial distribution characteristics of PM2.5, PM10, SO2, NO2, CO and O3 in five cities and the potential sources of PM10 in southern Xinjiang during 2016, we collected one year officially released data for analysis. The average PM10, PM2.5, SO2, NO2, O3 and CO concentrations were 289 ±â€¯363, 99 ±â€¯106, 17 ±â€¯9, 29 ±â€¯11, 65 ±â€¯25 µg m-3 and 1.3 ±â€¯0.6 mg m-3 in southern Xinjiang in 2016, respectively. The air pollutants presented distinct seasonal and spatial distribution characteristics. During sandstorm process, the particulate matters (PM) concentrations increased abruptly, with the PM10 and PM2.5 maximum concentrations exceeding 1000 and 500 µg m-3 in each city. The backward trajectory results showed that the air masses in Akesu, Kurla, Hotan, Kashi and Atushi were mainly from the Bayingol Mongolian Autonomous Prefecture, Kyrgyzstan, Kizilesu Kirgiz Autonomous Prefecture and Taklimakan Desert (TD). In addition, TD was the main potential contributor to ambient PM10 in five cities during the dust season (DS), with a weighted potential source contribution function (WPSCF) > 0.9. While the trajectories of air masses from TD, Bayingol Mongolian Autonomous Prefecture, Urumqi-Changji Area and local emission were potential sources contributing to PM2.5 in these five cities during DS, with a WPSCF > 0.7. Moreover, the high weighted concentration weighted trajectory (WCWT) values were distributed in the Tarim basin, with PM10 > 700 µg m-3, however, the local emission and long distance transport contributed to the PM2.5 > 160 µg m-3 for five cities. This study comprehensively analyzes the pollution characteristics of air pollutants in five important cities in the southern margin of the Tarim Basin for the first time, and will provide an important reference basis for the prevention and control of air pollution in southern Xinjiang.

5.
J Environ Sci (China) ; 71: 45-55, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30195689

RESUMO

Coal combustion in the domestic stoves, which is common in most parts of the Chinese countryside, can release harmful substances into the air and cause health issues. In this study, particles emitted from laboratory stove combustion of the raw powder coals were analyzed for morphologies and chemical compositions by using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectrometry (EDX). The coal burning-derived individual particles were classified into two groups: carbonaceous particles (including soot aggregates and organic particles) and non-carbonaceous particles (including sulfate, mineral and metal particles). The non-carbonaceous particles, which constituted a majority of the coal burning-derived emissions, were subdivided into Si-rich, S-rich, K-rich, Ca-rich, and Fe-rich particles according to the elemental compositions. The Si-rich, S-rich and K-rich particles are commonly observed in the coal burning emission. The proportions for particles of different types exhibit obvious coal-issue dependence. Burning of coal with high ash yield could emit more non-carbonaceous particles, and burning of coal with high sulfur content can emit more S-rich particles. By comparing the S-rich particles from this coal burning experiment with those in the atmosphere, we draw a conclusion that some S-rich particles in the atmosphere in China could be mainly sourced from coal combustion.


Assuntos
Poluentes Atmosféricos/análise , Carvão Mineral/análise , Culinária/instrumentação , Monitoramento Ambiental , Atmosfera/química , China , Culinária/estatística & dados numéricos
6.
Biosci Trends ; 11(2): 202-208, 2017 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-28420860

RESUMO

To determine the feasibility of using a nanoparticle immunoassay for clinical therapeutic drug monitoring (TDM) of docetaxel concentrations, a sensitive and simple method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established to measure the docetaxel concentration in human plasma and the results of LC-MS/MS and the immunoassay were compared. Docetaxel and paclitaxel (the internal standard, or IS) in human plasma were extracted through protein precipitation, separated on a Diamonsil C18 column (150 mm × 4.6 mm, 5 µm), ionized with positive ions, and detected with LC-MS/MS in multi-reaction monitoring (MRM) mode. Plasma samples from 248 cancer patients were assayed with LC-MS/MS and a nanoparticle immunoassay. Data from the samples were analyzed with the statistical software SPSS and the software MedCalc. Results indicated that the calibration curve of the validated method of LC-MS/MS was linear over the range of 10-2,000 ng/mL, with an lowest limit of quantitation (LLOQ) of 10 ng/mL, and the intra- and inter- day precision and accuracy were both < ± 15%. Comparison of the two methods indicated that results of the LC-MS/MS were closely related to those of the nanoparticle immunoassay, with a correlation coefficient (R) of 0.965 and acceptable 95% confidence intervals (CI) of ‒ 231.7-331.1 ng/mL. Overall, the established method of LC-MC/MS and the nanoparticle immunoassay were both suitable for measurement of the docetaxel concentration in human plasma, and the immunoassay was far more cost-effective and better at clinical TDM of docetaxel in clinical practice.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Imunoensaio/métodos , Espectrometria de Massas em Tandem/métodos , Taxoides/sangue , Docetaxel , Monitoramento de Medicamentos , Humanos , Nanopartículas/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-28407533

RESUMO

OBJECTIVES: The quassinoid brusatol, which can be isolated from Brucea javanica (L.) Merr., becomes popularly studied because of its anti-tumor activity. In order to further investigate brusatol and extend its applications, a sensitive analytical method for determination of brusatol in biological samples is essential. However, few methods had been reported until now. In this study, a highly sensitive and reproducible LC-MS method for simultaneous quantification of brusatol in mouse plasma and tissues was developed and validated. METHOD: Plasma samples and tissue homogenate were extracted with diethyl ether after addition of the internal standard solution(IS). The supernatant was blown to dryness with nitrogen and residual was reconstituted with 100µl of methanol. The separation was performed on an Intersil ODS-3 column and gradient elution was conducted with the mobile phase of water and methanol (0-5min 47:53, 5-5.5min 47:53-10:90, 5.5-9min 10:90, posttime 4min 47:53) at a flow rate of 0.8mL/min. Quantification was performed in the selected ion monitoring (SIM) mode at m/z 543.2 for brusatol and 220.0 for IS (ornidazole). The method was validated by analyzing quality control plasma and tissue homogenate samples, and was applied to analyze samples obtained from mice after injections of brusatol via the tail vein. RESULTS: With ornidazole as the internal standard, calibration curve of the method ranged from 10 to 320ng/ml for plasma and 10-240ng/ml for tissues. Recovery rate of brusatol from plasma and tissues were between 71.09%-94.91%. Relative standard deviation (RSD) for inter- and intra-day precision was less than 15%, and the accuracy was between 96.1%-111.8%. The pharmacokinetics and distribution study of brusatol in mice after three single doses via the tail vein were carried out based on this method. The concentration of brusatol in plasma decreased rapidly and a more than 10 fold concentration of brusatol was found as compared to that in other tissues. CONCLUSIONS: This is the first reported LC-MS method for detecting brusatol in tissues and can accurately determine the concentrations of these compounds in plasma and different tissues. Further research on the metabolism of brusatol in vivo is still needed.


Assuntos
Antineoplásicos Fitogênicos/farmacocinética , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas/métodos , Quassinas/farmacocinética , Animais , Antineoplásicos Fitogênicos/sangue , Antineoplásicos Fitogênicos/química , Brucea/química , Feminino , Limite de Detecção , Masculino , Camundongos , Quassinas/sangue , Quassinas/química , Distribuição Tecidual
8.
Am J Transl Res ; 8(10): 4195-4204, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27830003

RESUMO

OBJECTIVE: To investigate the effects of Bisphenol A (BPA) on prolactin (PRL) release, pituitary cell proliferation, prolactinoma formation in estrogen-sensitive Fischer 344 (F344) rats. MATERIALS AND METHODS: Four-week-old female F344 rats were orally administered with different concentrations of BPA or intraperitoneal injection of estradiol benzoate (estradiolbenzoate, E2) for 12 weeks. Bodyweight, blood RPL level and pituitary weights were observed and recorded. Real-time PCR, western blot and immunohistochemistry analysis were used to detect the mRNA and protein levels of the proliferation markers, including proliferating cell neclear antigen (PCNA), pituitary tumor-transforming gene (PTTG) and its relevant marker ERα. Plasma and urine BPA concentration in patients with prolactinoma and healthy participants were measured as well. RESULTS: Body weights of the rats treated with BPA were significantly decreased compared with those in the control group. The plasma PRL level and the pituitary weights of the rats were higher than those in the control group after BPA treatment. Compared with the control group, the pituitary mRNA and protein expression levels of PCNA and PTTG were significantly increased after BPA treatment. Moreover, ERα expression level was enhanced by the treatment of BPA in comparison with that of the control group. Finally, the plasma BPA concentration in the prolactin tumor patients was significantly higher than that in the healthy participants. CONCLUSION: BPA can significantly promote pituitary cell proliferation and prolactin secretion in F344 rats, which may have impact on the proliferation and secretion of pituitary cell function through the ERα pathway.

9.
J Environ Sci (China) ; 40: 28-34, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26969542

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic or mutagenic and are important toxic pollutants in the flue gas of boilers. Two industrial grade biomass boilers were selected to investigate the characteristics of particulate-bound PAHs: one biomass boiler retro-fitted from an oil boiler (BB1) and one specially designed (BB2) biomass boiler. One coal-fired boiler was also selected for comparison. By using a dilution tunnel system, particulate samples from boilers were collected and 10 PAH species were analyzed by gas chromatography-mass spectrometry (GC-MS). The total emission factors (EFs) of PAHs ranged from 0.0064 to 0.0380 mg/kg, with an average of 0.0225 mg/kg, for the biomass boiler emission samples. The total PAH EFs for the tested coal-fired boiler were 1.8 times lower than the average value of the biomass boilers. The PAH diagnostic ratios for wood pellets and straw pellets were similar. The ratio of indeno(1,2,3-cd)pyrene/[indeno(1,2,3-cd)pyrene+benzo(g,h,i)perylene] for the two biomass boilers was lower than those of the reference data for other burning devices, which can probably be used as an indicator to distinguish the emission of biomass boilers from that of industrial coal-fired boilers and residential stoves. The toxic potential of the emission from wood pellet burning was higher than that from straw pellet burning, however both of them were much lower than residential stove exhausts.


Assuntos
Poluentes Atmosféricos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Tecnologia , Poluentes Atmosféricos/toxicidade , Biocombustíveis , Biomassa , China , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Saúde Pública , Pirenos/análise , Tecnologia/instrumentação , Tecnologia/métodos
10.
Pak J Pharm Sci ; 29(6 Spec): 2245-2250, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28412689

RESUMO

Spikes in Lamotrigine concentrations levels and associated clinical toxicity may occur unpredictably. This study describes the development and validation of a simple, more rapid, highly sensitive and economical method for measuring Lamotrigine (LTG) concentration levels in human plasma using HPLC-UV and its clinical applications. Analyte from plasma was extracted with methanol (protein precipitation) and separated on the analytical column Diamonsil C18 (150mm×4.6mm, 5µm) Waters-Milford, MA, United States. Mixture of 0.1% Trifluoroacetate and Methanol used as mobile phase in a 59:41 volume/volume mixture with an isocratic flow rate of 1.5 ml/min and wavelength was adjusted to 260nm. Standard curve of lamotrigine showed good linearity over the range of 1.0-50µg/mL (r2=0.9961) and LLOQ was 1.0µg/ml. The Specificity, Recovery, Accuracy, Stability, Robustness and RSDs for both intraday and interday precision were within acceptable limits. The highly sensitive HPLC assay for determination of LTG in human plasma was demonstrated, validated and applied in Therapeutic Drug Monitoring (TDM) of sixty seven epilepsy patients who were using LTG. The proposed method can be easily applied in routine Therapeutic monitoring of LTG, Besides TDM, stated method can be also very useful for Bioequivalence studies, Pharmacovigilance and Pharmacokinetics studies.

11.
J Environ Sci (China) ; 26(1): 160-6, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24649702

RESUMO

Domestic coal stove is widely used in China, especially for countryside during heating period of winter, and polycyclic aromatic hydrocarbons (PAHs) are important in flue gas of the stove. By using dilution tunnel system, samples of both gaseous and particulate phases from domestic coal combustion were collected and 18 PAH species were analyzed by GC-MS. The average emission factors of total 18 PAH species was 171.73 mg/kg, ranging from 140.75 to 229.11 mg/kg for bituminous coals, while was 93.98 mg/kg, ranging from 58.48 to 129.47 mg/kg for anthracite coals. PAHs in gaseous phases occupied 95% of the total of PAHs emission of coal combustion. In particulate phase, 3-ring and 4-ring PAHs were the main components, accounting for 80% of the total particulate PAHs. The total toxicity potency evaluated by benzo[a]pyrene-equivalent carcinogenic power, sum of 7 carcinogenic PAH components and 2,3,7,8-tetrachlorodibenzodioxin had a similar tendency. And as a result, the toxic potential of bituminous coal was higher than that of anthracite coal. Efficient emission control should be conducted to reduce PAH emissions in order to protect ecosystem and human health.


Assuntos
Carvão Mineral , Gases/análise , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , China , Gases/toxicidade , Material Particulado/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade
12.
Environ Sci Process Impacts ; 15(3): 623-32, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23738361

RESUMO

Inhalatory and dermal exposures of on-duty vehicle inspection workers to polycyclic aromatic hydrocarbons (PAHs) in Beijing were investigated from April 18 to May 17, 2011. Exposure levels to particulate PAHs for the vehicle inspection workers at gasoline, bus and diesel lines were found to be 56.07 ng m(-3), 111.72 ng m(-3) and 199.80 ng m(-3), respectively. A probabilistic risk assessment framework was integrated with the toxic equivalence factors (TEFs) and the incremental lifetime cancer risk (ILCR) approaches to quantitatively estimate the exposure risk for vehicle inspection workers of the three work lines. The median values of inhalation risk were estimated to be 3.7 × 10(-7), 5.0 × 10(-7) and 1.37 × 10(-6), respectively, while the median dermal ILCR values were 7.05 × 10(-6), 6.98 × 10(-6) and 1.28 × 10(-5), respectively for gasoline, bus, and diesel inspection workers. Total ILCR was higher than the acceptable risk level of 10(-6), indicating unacceptable potential cancer risk.


Assuntos
Exposição por Inalação/análise , Neoplasias/etiologia , Exposição Ocupacional/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Monitoramento Ambiental , Humanos , Medição de Risco , Pele/efeitos dos fármacos , Local de Trabalho
13.
J Environ Sci (China) ; 24(1): 169-76, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22783629

RESUMO

Domestic coal stoves are widely used in countryside and greenbelt residents in China for heating and cooking, and emit considerable pollutants to the atmosphere because of no treatment of their exhaust, which can result in deteriorating local air quality. In this study, a dynamic smog chamber was used to investigate the real-time emissions of gaseous and particulate pollutants during the combustion process and a static smog chamber was used to investigate the fume evolution under simulate light irradiation. The real-time emissions revealed that the total hydrocarbon (THC) and CO increased sharply after ignition, and then quickly decreased, indicating volatilization of hydrocarbons with low molecular weight and incomplete combustion at the beginning stage of combustion made great contribution to these pollutants. There was evident shoulder peak around 10 min combustion for both THC and CO, revealing the emissions from vitrinite combustion. Additionally, another broad emission peak of CO after 30 min was also observed, which was ascribed to the incomplete combustion of the inertinite. Compared with THC and CO, there was only one emission peak for NOx, SO2 and particular matters at the beginning stage of combustion. The fume evolution with static chamber simulation indicated that evident consumption of SO2 and NOx as well as new particle formation were observed. The consumption rates for SO2 and NOx were about 3.44% hr(-1) and 3.68% hr(-1), the new particle formation of nuclei particles grew at a rate of 16.03 nm/hr during the first reaction hour, and the increase of the diameter of accumulation mode particles was evident. The addition of isoprene to the diluted mixture of the fume could promote 03 and secondary particle formation.


Assuntos
Carvão Mineral , Smog/efeitos adversos , Monóxido de Carbono/análise , Monitoramento Ambiental/métodos , Incineração , Smog/análise
14.
J Phys Chem A ; 116(7): 1710-6, 2012 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-22243138

RESUMO

The reaction of isoprene and methacrolein with ozone was investigated at different stages in the condensed phase at temperatures from 15 to 265 K by IR spectroscopy. The results revealed the following overall reaction process: the generation of primary ozonide (POZ), then its decomposition, and finally conversion into secondary ozonide (SOZ), which supported the Criegee mechanism. In the POZ and SOZ of isoprene, ozone cyclo-added preferentially to the double-bond that is not substituted by the methyl group. For methacrolein, the mainly detected SOZ is claimed to be MACSII formed by recombination of the intermediate CH(2)OO radical with aldehyde carbonyl of methylglyoxal in stead of the ketone carbonyl group. Theoretical calculations were performed at the B3LYP//MP2/6-311++G (2d, 2p) level to analyze the resulting spectrum. The good agreement between the calculated infrared spectra of POZ and SOZ and the experimental spectra supports the above-described findings.


Assuntos
Acroleína/análogos & derivados , Butadienos/química , Hemiterpenos/química , Ozônio/química , Pentanos/química , Acroleína/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente
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