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排序方式: 共有501条查询结果,搜索用时 18 毫秒
491.
Gallon C Ranville MA Conaway CH Landing WM Buck CS Morton PL Flegal AR 《Environmental science & technology》2011,45(23):9874-9882
Recent trends of atmospheric lead deposition to the North Pacific were investigated with analyses of lead in aerosols and surface waters collected on the fourth Intergovernmental Oceanographic Commission Contaminant Baseline Survey from May to June, 2002. Lead concentrations of the aerosols varied by 2 orders of magnitude (0.1-26.4 pmol/m(3)) due in part to variations in dust deposition during the cruise. The ranges in lead aerosol enrichment factors relative to iron (1-119) and aluminum (3-168) were similar, evidencing the transport of Asian industrial lead aerosols across the North Pacific. The oceanic deposition of some of those aerosols was substantiated by the gradient of lead concentrations of North Pacific waters, which varied 3-fold (32.7-103.5 pmol/kg), were highest along with the Asian margin of the basin, and decreased eastward. The hypothesized predominance of Asian industrial lead inputs to the North Pacific was further corroborated by the lead isotopic composition of ocean surface waters ((206)Pb/(207)Pb = 1.157-1.169; (208)Pb/(206)Pb = 2.093-2.118), which fell within the range of isotopic ratios reported in Asian aerosols that are primarily attributed to Chinese industrial lead emissions. 相似文献
492.
Taís Campos Scalise Mara Cristina Lopes de Oliveira Isaac Jamil Sayeg Renato Altobelli Antunes 《Journal of Materials Engineering and Performance》2014,23(6):2164-2173
Stainless steels employed for manufacturing automotive exhaust systems must withstand severe thermal cycles, corrosive environment due to urea decomposition, and welding operations. AISI 409 ferritic stainless steel can be considered a low-cost alternative for this application. However, depending on the manufacturing conditions during welding cycles, this material can be sensitized due to the precipitation of chromium carbides at grain boundaries. In this work, the intergranular corrosion resistances of the AISI 409 ferritic stainless steel were evaluated after annealing at 300, 500, and 700 °C for 2, 4, and 6 h. Solution-annealed samples were also tested for comparison purposes. Two methodologies were used to assess the sensitization behavior of the 409 stainless steel samples: the first one was based on the ASTM A763 (practice W), while the second one was based on the double-loop electrochemical potentiodynamic reactivation test. It was possible to identify that the annealing treatment performed at 500 °C was more critical to the occurrence of intergranular corrosion. 相似文献
493.
The inactivation and photoreactivation response of six seafood-isolated Listeria monocytogenes and one Listeria innocua strain after pulsed light (PL) treatment was evaluated. The lower inactivation levels found after exposure of treated samples to daylight during the first 90 min of storage confirmed that both L. innocua and L. monocytogenes have the capability to photorepair PL-induced DNA damage upon appropriate conditions. Photoreactivation levels from 0.2 to 2.1 log CFU cm?2 were observed depending on treatment intensity (fluence) and Listeria strain. Complete photorepair of PL-caused damage was not found even after treatments inducing low inactivation levels. Photoreactivation increased up to 2.1 log with the applied fluence up to a threshold able to cause between 2.4 and 5.4 log reductions under dark storage. Photorepair was not avoided but lower photoreactivation was observed after higher fluence inducing more than 6 log reductions under dark storage. Both L. innocua and L. monocytogenes serotype 1/2b exhibited the highest photoreactivation levels whereas serotypes 1/2a showed the lowest ones. The overall inactivation and photoreactivation responses of tested Listeria strains were comparable indicating that L. innocua may be a good surrogate for the safe evaluation, optimization and validation of PL technology to control L. monocytogenes in food products and food processing facilities. 相似文献
494.
The survival of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella was studied in apple, orange, pineapple, and white grape juice concentrates and banana puree. Pouches of juice concentrate or puree were inoculated with pathogens at a level > or = 10(3) CFU/g and stored at -23 degrees C (-10 degrees F). Pathogen survival was monitored at 6 and 24 h, once a week for four consecutive weeks, and biweekly thereafter until 12 weeks. When pathogens were not detectable by direct plating, samples were enriched in universal preenrichment broth for 72 h and plated on selective media. Results showed that E. coli O157:H7, L. monocytogenes, and Salmonella were recoverable from all five concentrates through 12 weeks of storage at -23 degrees C. 相似文献
495.
Gabriella Pasini Andrea Curioni Mara Vegro Mauro Pagani Antonio Masi Elisabetta Schievano Andrea Antico 《Journal of the science of food and agriculture》2012,92(3):570-576
BACKGROUND: Peach allergy can be caused by the allergen Pru p 1. This occurs by cross‐reactivity with the homologous birch pollen allergen Bet v 1. However, the direct identification of Pru p 1 as an immunoglobulin E (IgE)‐binding protein extracted from peach fruit has never been reported. RESULTS: Phosphate‐buffered saline (PBS) and phenol extractions were applied to solubilise the proteins from peach peel and pulp, and IgE immunoblotting with sera of individual peach‐allergic patients was used to detect the potential allergens. Most of the patients showed binding to an 18 kDa band in IgE immunoblotting performed with the phenolic extracts of peach peel and pulp, but not when the PBS extracts were used. Mass spectrometry of the 18 kDa spot excised from a two‐dimensional electrophoretic gel showed this protein to correspond to the peach allergen Pru p 1. CONCLUSION: Phenol extraction was necessary to detect by IgE immunoblotting a major peach allergen, which showed very low extractability with PBS, indicating the appropriateness of adopting different extraction procedures to identify plant allergens. The 18 kDa peach protein was definitively identified as the Bet v 1‐homologous peach allergen Pru p 1. Copyright © 2011 Society of Chemical Industry 相似文献
496.
L Iturriaga I Olabarrieta IM de Marañón 《International journal of food microbiology》2012,158(1):58-64
The antimicrobial activity of twelve natural extracts was tested against two fish spoilage bacteria (Pseudomonas fluorescens and Aeromonas hydrophila/caviae) and Listeria innocua, in order to assess their potential utilization in the preservation and safety of minimally processed fish products. After a screening of the active extracts by agar diffusion and vapour diffusion methods, oregano and thyme essential oils and citrus extract were selected. The minimum inhibitory concentration (MIC) of the selected extracts was determined by disc diffusion method against target bacteria and at two temperatures: bacteria's optimal growth temperature (30°C or 37°C) and refrigeration temperature (4°C). Due to its better solubility, lack of odour and greater inhibitory effect obtained against L. innocua at refrigerated temperature, citrus extract was selected and incorporated at 1% (v/v) into different biopolymer film forming solutions (gelatin, methyl cellulose and their blend 50:50 w/w). The antimicrobial activity of the developed films was then evaluated, just after preparation of the films and after one month of storage at 43±3% relative humidity and 24±3°C. Regardless of the biopolymer matrix, all the developed films showed antimicrobial activity against the target bacteria. The most sensitive bacterium towards active films was L. innocua while P. fluorescens appeared as the most resistant one, in accordance with the previously performed antimicrobial tests for pure extracts. The differences in activity of the films between the tested two temperatures were not significant except for L. innocua, for which three times higher inhibition diameters were observed at refrigerated temperature. The inhibitory effectiveness of the films against the tested strains was maintained regardless of the biopolymer matrix for at least one month. Therefore, these edible films show potential for their future use in fresh fish fillets preservation. 相似文献
497.
Carla Liaci Lucia Prandi Lisa Pavinato Alfredo Brusco Mara Maldotti Ivan Molineris Salvatore Oliviero Giorgio R. Merlo 《International journal of molecular sciences》2022,23(11)
In the human brain, long non-coding RNAs (lncRNAs) are widely expressed in an exquisitely temporally and spatially regulated manner, thus suggesting their contribution to normal brain development and their probable involvement in the molecular pathology of neurodevelopmental disorders (NDD). Bypassing the classic protein-centric conception of disease mechanisms, some studies have been conducted to identify and characterize the putative roles of non-coding sequences in the genetic pathogenesis and diagnosis of complex diseases. However, their involvement in NDD, and more specifically in intellectual disability (ID), is still poorly documented and only a few genomic alterations affecting the lncRNAs function and/or expression have been causally linked to the disease endophenotype. Considering that a significant fraction of patients still lacks a genetic or molecular explanation, we expect that a deeper investigation of the non-coding genome will unravel novel pathogenic mechanisms, opening new translational opportunities. Here, we present evidence of the possible involvement of many lncRNAs in the etiology of different forms of ID and NDD, grouping the candidate disease-genes in the most frequently affected cellular processes in which ID-risk genes were previously collected. We also illustrate new approaches for the identification and prioritization of NDD-risk lncRNAs, together with the current strategies to exploit them in diagnosis. 相似文献
498.
Micaela Garziano Olga Utyro Sergio Strizzi Claudia Vanetti Irma Saulle Chiara Conforti Federica Cicilano Francesco Ardizzone Gioia Cappelletti Mario Clerici Fiona Limanaqi Mara Biasin 《International journal of molecular sciences》2022,23(22)
The BNT162b2 vaccine induces neutralizing activity (NA) in serum, but no data are available on whether a third-dose activates specific-immunity within the oral mucosa, representing the primary route of viral-entry. To carefully address this issue, we investigated if such immunity is boosted by SARS-CoV-2-infection; how long it is maintained over-time; and if it protects against the SARS-CoV-2 lineage B.1 (EU) and the emerging Delta and Omicron variants. NA was measured in plasma and saliva samples from: uninfected SARS-CoV-2-Vaccinated (SV), subjects infected prior to vaccination (SIV), and subjects who were infected after the second (SIV2) or the third (SIV3) vaccine dose. Samples were collected immediately before (T0), 15 days (T1), and 90 days (T2) post third-dose administration (SV and SIV), or 15 days post-infection (SIV2 and SIV3). In all the enrolled groups, NA in plasma and saliva: (i) was higher against EU compared to the other variants at all time-points (SV: T0 and T1, EU vs. both Delta and Omicron p < 0.001; T2 p < 0.01) (SIV: T0, EU vs. Delta p < 0.05; EU vs. Omi p < 0.01; T1 and T2 EU vs. Delta p < 0.01; EU vs. Omi p < 0.001); (ii) was boosted by the administration of the third dose; iii) declined over-time, albeit being detectable in almost all subjects at T2. The monitoring of NA over time will be important in clarifying if different NA levels may influence either acquisition or course of infection to properly plan the timing of a fourth vaccine dose administration. 相似文献
499.
Gimerson Weigert Subtil Jean César Marinozi Vicentini Daiane Marques de Oliveira Lidiane Vizioli de Castro-Hoshino Patricia Hissae Yassue-Cordeiro Renata Corrêa Vicentino Mara Heloisa Neves Olsen Scaliante 《加拿大化工杂志》2023,101(3):1345-1357
The photocatalyst composition affects the chemical–physical properties and directly impacts photocatalytic activity, both in the hydrogen production and degradation of organic contaminants. In this work, the influence of zeolitic structures NaA, NaY, and ZSM-5 combined with a 10% active phase, TiO2 catalyst doped with 1% copper, and cobalt cocatalysts was tested to mineralize the reactive blue dye (CI250) and to produce hydrogen by photocatalysis under ultraviolet radiation. The band gap energy was affected mainly by the cocatalyst, while the Brunauer-Emmett-Teller method (BET) area was affected by the zeolite structure as well as the X-ray diffraction (XRD). The most active catalyst was the Cu@TiO2/NaY, which promoted a hydrogen production rate of 240 μmolH2gcat−1 using 10% ethanol (v/v) aqueous solution as a sacrificial agent and mineralization of 53% of the organic dye, followed by the catalysts impregnated on ZSM-5 zeolites, which had discolouration up to 50% and hydrogen evolution of 92.6 and 109.7 μmolH2gcat−1 for the catalyst doped with Cu and Co, respectively. 相似文献
500.
Mara Barani Rino Bonetti Wallace O. Parker Jr. 《Journal of the American Oil Chemists' Society》2023,100(7):551-560
Oxidative polymerization of plant oils and lipids is poorly understood yet widely encountered. Oils and fats are renewable resources providing biofuels and polymers. Oil oxidation is accelerated at high temperatures, typically above 110°C, where triacylglycerides are converted into toxic compounds and viscous deleterious polymers. Polymerization of mono-unsaturated oil (210°C, 3 h, open to air) was investigated by comparing four similar sized molecules with different functional groups: oleic acid, methyl oleate, trans-7-tetradecene, and stearic acid. Non-volatile products identified by NMR spectroscopy are minor ketones for saturated fatty acid (stearic acid), epoxides for acyl chains without acid groups (methyl oleate, tetradecane) and copious oligomerization, through ester cross-links, for acyl chains with acid, and olefinic groups (oleic acid). Long range C H coupling clearly shows ester (not ether) cross-links, contradicting long-held beliefs. Chain fragmentation also occurs for heated oleic acid as revealed by formation of a species with a methylene group bonded to oxygen of an ester, CH2 O C(O) . Large size (slow diffusion) of the first oligomer (trimer) formed from oleic acid, used to represent hydrolyzed vegetable oil, was evidenced by DOSY (diffusion-ordered spectroscopy). Combined NMR results show oligomers found in heated oleic acid are fatty acid estolides. Model oil reactions demonstrate why olefin and carboxylic acid groups are required for polymerization. 相似文献