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1.
Sci Total Environ ; 742: 140413, 2020 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-32623157

RESUMO

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous and contaminate soil, surface waters, atmospheric aerosol, precipitations, indoor and outdoor environments. However, the occurrence, transformation and fate of NPs in the environment are still unclear. In this work, polystyrene nanoparticles (PS-NPs) are used as a proxy of NPs to study their reactivity and potential impact on atmospheric and surface waters. In particular, the reactivity with hydroxyl radicals (OH) in the aqueous phase is investigated. For the first time, a reactivity constant for the reaction of NPs with OH is measured, strongly dependent on the exposed particle surface area of NPs. Degradation products (short chain carboxylic acids and aromatic compounds), obtained by direct and OH-mediated photolysis of PS-NPs suspensions, are identified by mass spectrometry. Irradiation of a PS-NPs suspension under natural sunlight for 1 year has shown the formation of formic acid and organic compounds similar to those found in riverine and cloud dissolved organic matter, which could contribute significantly to the dissolved organic matter in the aqueous phase.

2.
Ann Clin Microbiol Antimicrob ; 19(1): 24, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32487201

RESUMO

BACKGROUND: Carbapenem-resistant Klebsiella pneumoniae (CR-KP) is an urgent public health issue in Italy. This pattern of resistance is due mainly to dissemination of carbapenemase genes. Molecular characterization of carbapenem-resistant Klebsiella pneumoniae (CR-KP) strains was performed over a three-year period. In-depth analysis was performed on a subset of emerging CR-KP ST101 and ST307 clones. METHODS: A prospective study was performed on 691 patients with CR-KP bloodstream infections hospitalized in 19 hospitals located in three large provinces in Southern Italy. Carbapenemase genes were identified via genotyping methods. Multi-locus sequence typing (MLST) and Whole Genome Sequencing (WGS) were carried out on ST101 and ST307 isolates. RESULTS: Among the CR-KP isolates, blaKPC was found in 95.6%, blaVIM was found in 3.5%, blaNDM was found in 0.1% and blaOXA-48 was found in 0.1%. The blaKPC-3 variant was identified in all 104 characterized KPC-KP isolates. MLST of 231 representative isolates revealed ST512 in 45.5%, ST101 in 20.3% and ST307 in 18.2% of the isolates. cgMLST of ST307 and ST101 isolates revealed presence of more than one beta-lactam resistance gene. Amino acid substitution in the chromosomal colistin-resistance gene pmrB was found in two ST101 isolates. CONCLUSIONS: ST512 is widespread in Southern Italy, but ST101 and ST307 are emerging since they were found in a significant proportion of cases. Aggressive infection control measures and a continuous monitoring of these high-risk clones are necessary to avoid rapid spread of CR-KP, especially in hospital settings.

3.
Comp Immunol Microbiol Infect Dis ; 70: 101471, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32208190

RESUMO

In this study, the isolation of Acinetobacter baumannii in a dog with clinical bilateral otitis externa is described. Moreover, to investigate the zoonotic potential of the isolate, microbiological examinations on the family members were performed. An A. baumanniistrain was isolated from nasal swab in one of the dog owners. The identity of bacterial strains, either from dog and owner, was confirmed by phenotypic and molecular typing (wgMLST). Furthermore, to assess the pathogenic potential of the isolates a deep characterization of virulence and antibiotic resistance genes was done by Whole Genome Sequencing (WGS). Finally, the susceptibility towards a wide panel of antimicrobials was investigated. In our knowledge, this is the first recorded case of A. baumanniiisolation from canine auricular swabs in Italy. And interestingly, this study underlines the possible spread of this microorganism from human to animal.

4.
Microb Drug Resist ; 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32101078

RESUMO

Objective: Helicobacter pylori antibiotic resistance is a constantly evolving process and local surveillance is warranted to guide clinicians in the choice of therapy. Materials and Methods: Antibiotic susceptibility testing was performed by E-test on 92 H. pylori strains, and resistance to clarithromycin and levofloxacin was also evaluated using a commercially available genotyping method. Results: In naïve patients the resistance to clarithromycin, levofloxacin, and metronidazole was 37.7%, 26.2%, and 16.4%, respectively, significantly lower than the percentage found in treated patients. Concomitant resistance to ≥2 antibiotics was also observed in naïve patients. The A2143G mutation of the 23S-rRNA gene was the most frequently detected, also in naïve patients. The highest minimum inhibitory concentration (MIC)50 value (256 mg/L) was associated with A2142 mutations in all the patients carrying them. For levofloxacin resistance a mutation in codon 87 was detected in 63.9% and in codon 91 in 36.1% of the H. pylori strains, without significant differences in the patients groups. A mutation in codon 87 was associated with the highest MIC50 value (32 mg/L). Conclusions: In our area, a high prevalence of H. pylori primary resistance was detected; these rates were higher in patients who had experienced failure of several courses of therapy. A better knowledge of the local epidemiology of resistance, and the genotypes responsible, will improve the H. pylori eradication rates.

5.
Molecules ; 25(2)2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31968643

RESUMO

This review paper describes briefly the cloud aqueous phase composition and deeply its reactivity in the dark and mainly under solar radiation. The role of the main oxidants (hydrogen peroxide, nitrate radical, and hydroxyl radical) is presented with a focus on the hydroxyl radical, which drives the oxidation capacity during the day. Its sources in the aqueous phase, mainly through photochemical mechanisms with H2O2, iron complexes, or nitrate/nitrite ions, are presented in detail. The formation rate of hydroxyl radical and its steady state concentration evaluated by different authors are listed and compared. Finally, a paragraph is also dedicated to the sinks and the reactivity of the HO• radical with the main compounds found in the cloud aqueous phase. This review presents an assessment of the reactivity in the cloud aqueous phase and shows the significant potential impact that this medium can have on the chemistry of the atmosphere and more generally on the climate.

7.
Ital J Food Saf ; 8(2): 7840, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31236384

RESUMO

Arcobacter butzleri is a pathogenic aerobic bacterium responsible for diarrhea and septicemia in humans. It is frequently isolated from food products of animal origin, including milk and dairy products. To data, few reports are currently available on the genetic characteristics and virulence profiles of A. butzleri. The aim of this study was to investigate the genetic diversity and to characterize the virulence and antibiotic resistance profiles of 10 A. butzleri strains isolated from bovine milk samples by Whole Genome Sequence (WGS). Multi-Locus Sequence Typing (MLST) revealed that three isolates belonged to the ST66, two to the ST420 and the remaining five strains to the ST627, ST629, ST630, ST633 and ST637, respectively. The 100% of the strains carried cadF, pldA, ciaB, cj1349, mviN and tlyA virulence factors genes; 60% iroE; 50% irgA; 10% hecB. Resistome prediction showed a multidrug resistance: 100% of isolates resulted resistant to fluoroquinolones and tetracycline; 90% of strains to rifampicin and cephalosporins and a minor percentage to other antibiotics. Furthermore, the 50% of strains harbored four mutations in Mycobacterium tuberculosis katG gene conferring resistance to isoniazid. The study provided interesting data on the virulence characteristics and on the genetic endowment related to the antimicrobial resistance of A. butzleri isolates from milk. The determination of the STs also added information concerning the genetic variability of this microorganism. To date, a very limited number of studies have been published on the typing of A. butzleri using WGS, so this paper proposes an innovative methodological approach that allows a rapid and complete characterization of pathogenic microorganisms.

8.
Acta Trop ; 197: 105058, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31185223

RESUMO

Vector-borne diseases (VBDs) of domestic and wild carnivores are of major public health concern both in industrialized and developing countries, especially in poor socioeconomic settings. War-torn areas specifically suffer from absence of veterinary surveillance of VBDs, resulting in lack of scientific knowledge on this topic. To investigate occurence and prevalence of several vector-borne pathogens (VBPs) in some carnivore species from Iraq, blood samples (n = 397) were obtained from 190 canids [97 stray dogs (Canis familiaris), 55 jackals (Canis aureus) and 38 red foxes (Vulpes vulpes)] and 207 stray cats (Felis catus) collected during a feral animal control and zoonotic disease surveillance program in several United States military bases in Iraq. The presence of Babesia spp., Hepatozoon spp., Ehrlichia spp., Anaplasma spp., Dirofilaria spp. and Leishmania spp. DNA was molecularly investigated. Out of 397 animals tested, 176 (44.3%; 95% CI: 39.5-49.2%) were positive for at least one pathogen with the highest prevalence in foxes (73.7%; 95% CI: 58-85%), followed by jackals (54.5%; 95% CI: 41.5-67%), dogs (38.1%; 29.1-48.1%) and cats (39.1%; 95% CI: 32.7-45.9%). Up to five pathogens were diagnosed in dogs. Hepatozoon canis was the most prevalent VBP in jackals (49.1%; 95% CI: 36.4-61.9%), foxes (47.3%; 95% CI: 32.5-62.7%) and dogs (33%; 95% CI: 24.4-42.8%), whereas Hepatozoon felis was the only species detected in cats (39.1%; 95% CI: 32.7-45.9%). A species of Babesia related to but different from Babesia lengau and designated as Babesia sp. MML was detected in six foxes (15.8%; 95% CI: 7.4-30.4%) and in one jackal (1.8%; 95% CI: 0.3-9.6%). This finding suggested the existence of a new species in the genus Babesia as inferred by molecular and phylogenetical analysis. Further, Babesia vulpes was identified only in two foxes (5.3%; 95% CI: 1.5-17.3%). All samples were negative for Leishmania spp. and Ehrlichia spp. Co-infection with H. canis and Babesia spp. was the most prevalent (5/176, 2.8%, i.e., 4 foxes and 1 jackal), followed by H. canis and Dirofilaria immitis (1/176, 1.3%, i.e., in 1 jackal), H. canis and Dirofilaria repens or Acanthocheilonema reconditum (1/176, 1.3%, i.e., in one dog, each). Data presented fill gaps into knowledge of VBPs in dogs, cats and wild canids in Iraq, indicating that different pathogens circulate amongst animal populations living in the same areas, possibly sharing the same tick vectors. Large-scale surveys are urgently needed to further assess VBPs distribution in Iraq and establish preventative strategies in domestic animals to minimize the risk of infection for animals and humans.


Assuntos
Gatos/parasitologia , Cães/parasitologia , Raposas/parasitologia , Chacais/parasitologia , Anaplasma/isolamento & purificação , Animais , Babesia/isolamento & purificação , Gatos/microbiologia , Vetores de Doenças , Cães/microbiologia , Ehrlichia/isolamento & purificação , Feminino , Raposas/microbiologia , Iraque/epidemiologia , Chacais/microbiologia , Leishmania/isolamento & purificação , Masculino , Prevalência
9.
Sci Rep ; 9(1): 7663, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31113999

RESUMO

A cloud water sample collected at the puy de Dôme observatory (PUY) has been incubated under dark conditions, with its endogenous microbiota at two different temperatures (5 and 15 °C), and the change in the molecular organic composition of this sample was analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Microorganisms were metabolically active and strongly modified the dissolved organic matter since they were able to form and consume many compounds. Using Venn diagrams, four fractions of compounds were identified: (1) compounds consumed by microbial activity; (2) compounds not transformed during incubation; (3) compounds resulting from dark chemistry (i.e., hydrolysis and Fenton reactions) and, finally, (4) compounds resulting from microbial metabolic activity. At 15 °C, microorganisms were able to consume 58% of the compounds initially present and produce 266 new compounds. For this cloud sample, the impact of dark chemistry was negligible. Decreasing the temperature to 5 °C led to the more efficient degradation of organic compounds (1716 compounds vs. 1094 at 15 °C) but with the less important production of new ones (173). These transformations were analyzed using a division into classes based on the O/C and H/C ratios: lipid-like compounds, aliphatic/peptide-like compounds, carboxylic-rich alicyclic molecule (CRAM)-like structures, carbohydrate-like compounds, unsaturated hydrocarbons, aromatic structures and highly oxygenated compounds (HOCs). Lipid-like, aliphatic/peptide-like and CRAMs-like compounds were the most impacted since they were consumed to maintain the microbial metabolism. On the contrary, the relative percentages of CRAMs and carbohydrates increased after incubation.

10.
BMC Res Notes ; 11(1): 911, 2018 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-30572950

RESUMO

OBJECTIVES: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease characterized by a variable and reduced penetrance. Individuals carrying a primary LHON-causing mitochondrial DNA (mtDNA) mutation may either remain asymptomatic lifelong, as unaffected carriers, or develop sudden central visual loss that rapidly aggravates over some weeks. Over the years several genetic/environmental triggers able to modulate the risk of developing LHON have been proposed. We provided data supporting a possible correlation between LHON penetrance and the mtDNA copy number, a raw index of mitochondrial mass, whose increase could represent a compensatory response that cells implement to alleviate the pathogenic effect of the primary LHON-causing mtDNA mutations. DATA DESCRIPTION: We collected Italian and Spanish subjects harboring one of the three common LHON primary mutations, either in heteroplasmic or homoplasmic status. For each population we were able to discriminate between affected subjects presenting typical clinical tracts of LHON and LHON-causing mutation carriers showing no symptoms correlated with vision loss. Each subject has been characterized for the presence of a LHON primary mutation, for its status of homoplasmy or heteroplasmy, and for the mtDNA content per cell, expressed as relative mtDNA/nDNA ratio respect to controls. Additional clinical information is present for all the Italian subjects.


Assuntos
Variações do Número de Cópias de DNA/genética , DNA Mitocondrial/genética , Atrofia Óptica Hereditária de Leber/genética , Penetrância , Feminino , Heterozigoto , Humanos , Itália , Masculino , Mutação , Atrofia Óptica Hereditária de Leber/patologia , Atrofia Óptica Hereditária de Leber/fisiopatologia , Linhagem , Espanha
11.
BMC Med Genet ; 19(1): 129, 2018 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-30053855

RESUMO

BACKGROUND: Leber's hereditary optic neuropathy (LHON) associated with mutations in mitochondrial DNA (mtDNA) typically manifests only optic nerve involvement but in some patients may develop additional neurological complications. The cause of this association is not clear. CASE PRESENTATION: We present a case of a 24-year-old male with a history of subacute, painless, and rapidly progressive bilateral vision loss. We performed ophthalmological, neurological and neuropsychological investigations in the proband and his LHON family. The proband showed optic neuropathy, epilepsy, migraine, and intellectual disability; all the maternal relatives did not manifest optic neuropathy but a moderate to severe intellectual disability. Genetic screening revealed a novel association of the LHON m.3460G > A primary mutation with the m.T961delT + C(n)ins within the mitochondrial encoded 12S RNA (MTRNR1) gene which segregates with the intellectual disability through the maternal branch of the family. We also found a significant increase of mtDNA content in all the unaffected homo/heteroplasmic mutation carriers with respect to either affected or control subjects. CONCLUSION: This is the first case reporting the co-segregation of a mutation in MTRNR1 gene with a LHON primary mutation, which may be a risk factor of the extraocular signs complicating LHON phenotype. In addition, the data herein reported, confirmed that the key factor modulating the penetrance of optic atrophy in the family is the amount of mtDNA.


Assuntos
DNA Mitocondrial/genética , Epilepsia/genética , Deficiência Intelectual/genética , Mutação/genética , Atrofia Óptica Hereditária de Leber/genética , RNA Ribossômico/genética , Adulto , Idoso , Feminino , Humanos , Masculino , Repetições de Microssatélites/genética , Pessoa de Meia-Idade , Mitocôndrias/genética , Linhagem , Penetrância , Adulto Jovem
12.
Environ Sci Technol ; 52(18): 10275-10285, 2018 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-30052429

RESUMO

Cloud droplets contain dynamic and complex pools of highly heterogeneous organic matter, resulting from the dissolution of both water-soluble organic carbon in atmospheric aerosol particles and gas-phase soluble species, and are constantly impacted by chemical, photochemical, and biological transformations. Cloud samples from two summer events, characterized by different air masses and physicochemical properties, were collected at the Puy de Dôme station in France, concentrated on a strata-X solid-phase extraction cartridge and directly infused using electrospray ionization in the negative mode coupled with ultrahigh-resolution mass spectrometry. A significantly higher number (n = 5258) of monoisotopic molecular formulas, assigned to CHO, CHNO, CHSO, and CHNSO, were identified in the cloud sample whose air mass had passed over the highly urbanized Paris region (J1) compared to the cloud sample whose air mass had passed over remote areas (n = 2896; J2). Van Krevelen diagrams revealed that lignins/CRAM-like, aliphatics/proteins-like, and lipids-like compounds were the most abundant classes in both samples. Comparison of our results with previously published data sets on atmospheric aqueous media indicated that the average O/C ratios reported in this work (0.37) are similar to those reported for fog water and for biogenic aerosols but are lower than the values measured for aerosols sampled in the atmosphere and for aerosols produced artificially in environmental chambers.


Assuntos
Ciclotrons , Aerossóis , Análise de Fourier , França , Espectrometria de Massas
14.
J Hazard Mater ; 347: 279-287, 2018 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-29329010

RESUMO

In the present work we investigate the activation efficiency of H2O2 and S2O82- using UVA and UVB radiation. Bisphenol-A (BPA) is used as model pollutants to estimate the oxidative process efficiency in simulated and real sewage treatment plant waters. Particular attention is paid to the BPA removal efficiency and to the radical mechanism involvement considering the effect of typical inorganic water constituents (carbonates and chloride ions) and organic matter. Despite a detrimental effect observed when carbonate ions are in solution using both hydrogen peroxide and persulafate, the presence of high chloride ions concentration was found to improve BPA removal using S2O82- as radical precursor. This enhancement, investigated combining chemical kinetic model approach and laser flash photolysis experiments, is attributed to the formation of hydroxyl radical and chlorine radical species from sulfate radical. Different transformation products are identified by means of GC-MS and HPLC-MS analyses. Moreover, experiments using sewage treatment plant water (STPW) spiked with BPA are performed in order to assess the efficiency of oxidative processes in a simulated treatment systems activated using UVA + UVB radiations.

16.
Invest Ophthalmol Vis Sci ; 58(4): 2193-2197, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28403426

RESUMO

Purpose: Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease that typically causes bilateral blindness in young men. It is characterized by as yet undisclosed genetic and environmental factors affecting the incomplete penetrance. Methods: We identified 27 LHON subjects who possess heteroplasmic primary LHON mutations. Mitochondrial DNA (mtDNA) copy number was evaluated. Results: The presence of centrocecal scotoma, an edematous, hyperemic optic nerve head, and vascular tortuosity, as well as telangiectasia was recognized in affected subjects. We found higher cellular mtDNA content in peripheral blood cells of unaffected heteroplasmic mutation carriers with respect to the affected. Conclusions: The increase of cellular mtDNA content prevents complete loss of vision despite the presence of a heteroplasmic state of LHON primary mutation, suggesting that it is a key factor responsible for penetrance of LHON.


Assuntos
Cegueira/prevenção & controle , Variações do Número de Cópias de DNA , DNA Mitocondrial/genética , Mitocôndrias/genética , Doenças Mitocondriais/genética , Mutação , Atrofia Óptica Hereditária de Leber/genética , Antioxidantes/uso terapêutico , Feminino , Genes Mitocondriais/genética , Humanos , Masculino , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/tratamento farmacológico , Atrofia Óptica Hereditária de Leber/diagnóstico , Atrofia Óptica Hereditária de Leber/tratamento farmacológico , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Ubiquinona/análogos & derivados , Ubiquinona/uso terapêutico , Acuidade Visual
17.
Acta Myol ; 36(3): 163-177, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29774306

RESUMO

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes severe loss of sight in young adults, and is typically associated to mitochondrial DNA (mtDNA) mutations. Heteroplasmy of primary LHON mutations, presence of 'ancillary' mtDNA mutations, and mtDNA copy number are probably correlated with the penetrance and the severity of the disease. In this study, we performed a mutational screening in an Apulian cohort of LHON patients and we found that 41 out of 54 subjects harbored the m.11778G>A mutation, and 13 harbored the m.3460G>A mutation. Whole mtDNA sequencing was performed in three affected subjects belonging to three unrelated m.11778G>A pedigrees to evaluate the putative synergistic role of additional mtDNA mutations in determining the phenotype. Our study suggests to include haplogroup T as a possible genetic background influencing LHON penetrance and to consider the increase of mtDNA copy number as a protective factor from vision loss regardless the hetero/homoplasmic status of LHON primary mutations.


Assuntos
DNA Mitocondrial/análise , Complexo I de Transporte de Elétrons/genética , Atrofia Óptica Hereditária de Leber/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise Mutacional de DNA , Feminino , Dosagem de Genes , Heterozigoto , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Mutação , Penetrância , Fenótipo , Adulto Jovem
18.
Sci Rep ; 6: 37420, 2016 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-27876758

RESUMO

Improving our understanding of cloud chemistry depends on achieving better chemical characterization (90% of the organic carbon [OC] fraction remains uncharacterized) and, consequently, assessing the reactivity of this complex system. In this manuscript, we report for the first time the concentrations of 16 amino acids (AAs) in 25 cloud water samples. The concentrations of individual AAs ranged from a few nM up to ~2.0 µM, and the average contribution of AAs corresponded to 9.1% (4.4 to 21.6%) of the dissolved OC (DOC) concentration. Considering their occurrence and concentrations, AAs were expected to represent an important hydroxyl radical (HO•) sink in aqueous cloud samples. In this work, we estimated that approximately 17% (from 7 to 36%) of the hydroxyl radical-scavenging ability of the DOC could be attributed to the presence of AAs, whereas comparing the AAs suggested that an average of 51% (from 22 to 80%) of their reactivity with HO• could account for the presence of tryptophan. These results clearly demonstrate that the occurrence and reactivity of AAs must be considered to better estimate the chemical composition and oxidant capacity of the cloud aqueous phase.


Assuntos
Aminoácidos/química , Carbono/química , Compostos Orgânicos/química , Água/química , Radical Hidroxila/química , Oxidantes/química , Triptofano/química
19.
Environ Sci Technol ; 50(20): 11041-11048, 2016 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-27611489

RESUMO

Interfaces are ubiquitous in the environment and many atmospheric key processes, such as gas deposition, aerosol, and cloud formation are, at one stage or another, strongly impacted by physical and chemical processes occurring at interfaces. Here, the photoinduced chemistry of an air/water interface coated with nonanoic acid-a fatty acid surfactant we use as a proxy for chemically complex natural aqueous surface microlayers-was investigated as a source of volatile and semivolatile reactive organic species. The carboxylic acid coating significantly increased the propensity of photosensitizers, chosen to mimic those observed in real environmental waters, to partition to the interface and enhance reactivity there. Photochemical formation of functionalized and unsaturated compounds was systematically observed upon irradiation of these coated surfaces. The role of a coated interface appears to be critical in providing a concentrated medium allowing radical-radical reactions to occur in parallel with molecular oxygen additions. Mechanistic insights are provided from extensive analysis of products observed in both gas and aqueous phases by online switchable reagent ion-time of flight-mass spectrometry and by off-line ultraperformance liquid chromatography coupled to a Q Exactive high resolution mass spectrometer through heated electrospray ionization, respectively.


Assuntos
Processos Fotoquímicos , Água/química , Aerossóis , Fenômenos Químicos , Ácidos Graxos
20.
Science ; 353(6300): 699-702, 2016 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-27516601

RESUMO

Although fatty acids are believed to be photochemically inert in the actinic region, complex volatile organic compounds are produced during illumination of an air-water interface coated solely with a monolayer of carboxylic acid. When aqueous solutions containing nonanoic acid (NA) at bulk concentrations that give rise to just over a monolayer of NA coverage are illuminated with actinic radiation, saturated and unsaturated aldehydes are seen in the gas phase, and more highly oxygenated products appear in the aqueous phase. This chemistry is probably initiated by triplet-state NA molecules excited by direct absorption of actinic light at the water surface. Because fatty acids-covered interfaces are ubiquitous in the environment, such photochemical processing will have a substantial impact on local ozone and particle formation.

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