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1.
Virol J ; 21(1): 70, 2024 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-38515117

RESUMO

Since the emergence of SARS-CoV-2, different variants and subvariants successively emerged to dominate global virus circulation as a result of immune evasion, replication fitness or both. COVID-19 vaccines continue to be updated in response to the emergence of antigenically divergent viruses, the first being the bivalent RNA vaccines that encodes for both the Wuhan-like and Omicron BA.5 subvariant spike proteins. Repeated infections and vaccine breakthrough infections have led to complex immune landscapes in populations making it increasingly difficult to assess the intrinsic neutralizing antibody responses elicited by the vaccines. Hong Kong's intensive COVID-19 containment policy through 2020-2021 permitted us to identify sera from a small number of infection-naïve individuals who received 3 doses of the RNA BNT162b2 vaccine encoding the Wuhan-like spike (WT) and were boosted with a fourth dose of the WT vaccine or the bivalent WT and BA.4/5 spike (WT + BA.4/5). While neutralizing antibody to wild-type virus was comparable in both vaccine groups, BNT162b2 (WT + BA.4/BA.5) bivalent vaccine elicited significantly higher plaque neutralizing antibodies to Omicron subvariants BA.5, XBB.1.5, XBB.1.16, XBB.1.9.1, XBB.2.3.2, EG.5.1, HK.3, BA.2.86 and JN.1, compared to BNT162b2 monovalent vaccine. The single amino acid substitution that differentiates the spike of JN.1 from BA.2.86 resulted in a profound antigenic change.


Assuntos
Vacina BNT162 , COVID-19 , Humanos , Anticorpos Amplamente Neutralizantes , SARS-CoV-2/genética , Vacinas contra COVID-19 , COVID-19/prevenção & controle , Anticorpos Neutralizantes , Vacinação , Anticorpos Antivirais
2.
Environ Sci Technol ; 57(5): 1870-1881, 2023 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-36695819

RESUMO

We report aircraft observations of extreme levels of HCl and the dihalogens Cl2, Br2, and BrCl in an industrial plume near the Great Salt Lake, Utah. Complete depletion of O3 was observed concurrently with halogen enhancements as a direct result of photochemically produced halogen radicals. Observed fluxes for Cl2, HCl, and NOx agreed with facility-reported emissions inventories. Bromine emissions are not required to be reported in the inventory, but are estimated as 173 Mg year-1 Br2 and 949 Mg year-1 BrCl, representing a major uncounted oxidant source. A zero-dimensional photochemical box model reproduced the observed O3 depletions and demonstrated that bromine radical cycling was principally responsible for the rapid O3 depletion. Inclusion of observed halogen emissions in both the box model and a 3D chemical model showed significant increases in oxidants and particulate matter (PM2.5) in the populated regions of the Great Salt Lake Basin, where winter PM2.5 is among the most severe air quality issues in the U.S. The model shows regional PM2.5 increases of 10%-25% attributable to this single industrial halogen source, demonstrating the impact of underreported industrial bromine emissions on oxidation sources and air quality within a major urban area of the western U.S.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Perda de Ozônio , Ozônio , Poluentes Atmosféricos/análise , Halogênios , Ozônio/análise , Bromo , Lagos , Poluição do Ar/análise , Material Particulado/análise , Oxidantes
3.
Proc Natl Acad Sci U S A ; 117(47): 29469-29477, 2020 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-33148807

RESUMO

The evolution of organic aerosol (OA) and brown carbon (BrC) in wildfire plumes, including the relative contributions of primary versus secondary sources, has been uncertain in part because of limited knowledge of the precursor emissions and the chemical environment of smoke plumes. We made airborne measurements of a suite of reactive trace gases, particle composition, and optical properties in fresh western US wildfire smoke in July through August 2018. We use these observations to quantify primary versus secondary sources of biomass-burning OA (BBPOA versus BBSOA) and BrC in wildfire plumes. When a daytime wildfire plume dilutes by a factor of 5 to 10, we estimate that up to one-third of the primary OA has evaporated and subsequently reacted to form BBSOA with near unit yield. The reactions of measured BBSOA precursors contribute only 13 ± 3% of the total BBSOA source, with evaporated BBPOA comprising the rest. We find that oxidation of phenolic compounds contributes the majority of BBSOA from emitted vapors. The corresponding particulate nitrophenolic compounds are estimated to explain 29 ± 15% of average BrC light absorption at 405 nm (BrC Abs405) measured in the first few hours of plume evolution, despite accounting for just 4 ± 2% of average OA mass. These measurements provide quantitative constraints on the role of dilution-driven evaporation of OA and subsequent radical-driven oxidation on the fate of biomass-burning OA and BrC in daytime wildfire plumes and point to the need to understand how processing of nighttime emissions differs.


Assuntos
Poluentes Atmosféricos/química , Carbono/análise , Fumaça , Incêndios Florestais , Aerossóis , Monitoramento Ambiental , Material Particulado , Estados Unidos
4.
Geophys Res Lett ; 49(11): e2021GL097366, 2022 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-35859850

RESUMO

Oxidation of isoprene by nitrate radicals (NO3) or by hydroxyl radicals (OH) under high NOx conditions forms a substantial amount of organonitrates (ONs). ONs impact NOx concentrations and consequently ozone formation while also contributing to secondary organic aerosol. Here we show that the ONs with the chemical formula C4H7NO5 are a significant fraction of isoprene-derived ONs, based on chamber experiments and ambient measurements from different sites around the globe. From chamber experiments we found that C4H7NO5 isomers contribute 5%-17% of all measured ONs formed during nighttime and constitute more than 40% of the measured ONs after further daytime oxidation. In ambient measurements C4H7NO5 isomers usually dominate both nighttime and daytime, implying a long residence time compared to C5 ONs which are removed more rapidly. We propose potential nighttime sources and secondary formation pathways, and test them using a box model with an updated isoprene oxidation scheme.

5.
Proc Natl Acad Sci U S A ; 116(14): 6641-6646, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30886090

RESUMO

Atmospheric oxidation of natural and anthropogenic volatile organic compounds (VOCs) leads to secondary organic aerosol (SOA), which constitutes a major and often dominant component of atmospheric fine particulate matter (PM2.5). Recent work demonstrates that rapid autoxidation of organic peroxy radicals (RO2) formed during VOC oxidation results in highly oxygenated organic molecules (HOM) that efficiently form SOA. As NOx emissions decrease, the chemical regime of the atmosphere changes to one in which RO2 autoxidation becomes increasingly important, potentially increasing PM2.5, while oxidant availability driving RO2 formation rates simultaneously declines, possibly slowing regional PM2.5 formation. Using a suite of in situ aircraft observations and laboratory studies of HOM, together with a detailed molecular mechanism, we show that although autoxidation in an archetypal biogenic VOC system becomes more competitive as NOx decreases, absolute HOM production rates decrease due to oxidant reductions, leading to an overall positive coupling between anthropogenic NOx and localized biogenic SOA from autoxidation. This effect is observed in the Atlanta, Georgia, urban plume where HOM is enhanced in the presence of elevated NO, and predictions for Guangzhou, China, where increasing HOM-RO2 production coincides with increases in NO from 1990 to 2010. These results suggest added benefits to PM2.5 abatement strategies come with NOx emission reductions and have implications for aerosol-climate interactions due to changes in global SOA resulting from NOx interactions since the preindustrial era.

6.
Acc Chem Res ; 53(8): 1415-1426, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32648739

RESUMO

ConspectusThe complex array of sources and transformations of organic carbonaceous material that comprises an important fraction of atmospheric fine particle mass, known as organic aerosol, has presented a long running challenge for accurate predictions of its abundance, distribution, and sensitivity to anthropogenic activities. Uncertainties about changes in atmospheric aerosol particle sources and abundance over time translate to uncertainties in their impact on Earth's climate and their response to changes in air quality policy. One limitation in our understanding of organic aerosol has been a lack of comprehensive measurements of its molecular composition and volatility, which can elucidate sources and processes affecting its abundance. Herein we describe advances in the development and application of the Filter Inlet for Gases and Aerosols (FIGAERO) coupled to field-deployable High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometers (HRToF-CIMS). The FIGAERO HRToFCIMS combination broadly probes gas and particulate OA molecular composition by using programmed thermal desorption of particles collected on a Teflon filter with subsequent detection and speciation of desorbed vapors using inherently quantitative selected-ion chemical ionization. The thermal desorption provides a means to obtain quantitative insights into the volatility of particle components and thus the physicochemical nature of the organic material that will govern its evolution in the atmosphere.In this Account, we discuss the design and operation of the FIGAERO, when coupled to the HRToF-CIMS, for quantitative characterization of the molecular-level composition and effective volatility of organic aerosol in the laboratory and field. We provide example insights gleaned from its deployment, which improve our understanding of organic aerosol sources and evolution. Specifically, we connect thermal desorption profiles to the effective equilibrium saturation vapor concentration and enthalpy of vaporization of detected components. We also show how application of the FIGAERO HRToF-CIMS to environmental simulation chamber experiments and the field provide new insights and constraints on the chemical mechanisms governing secondary organic aerosol formation and dynamic evolution. We discuss the associated challenges of thermal decomposition during desorption and calibration of both the volatility axis and signal. We also illustrate how the FIGAERO HRToF-CIMS can provide additional insights into organic aerosol through isothermal evaporation experiments as well as for detection of ultrafine particulate composition. We conclude with a description of future opportunities and needs for its ability to further organic aerosol science.

7.
Proc Natl Acad Sci U S A ; 115(32): 8110-8115, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-30037992

RESUMO

Sulfate ([Formula: see text]) and nitrate ([Formula: see text]) account for half of the fine particulate matter mass over the eastern United States. Their wintertime concentrations have changed little in the past decade despite considerable precursor emissions reductions. The reasons for this have remained unclear because detailed observations to constrain the wintertime gas-particle chemical system have been lacking. We use extensive airborne observations over the eastern United States from the 2015 Wintertime Investigation of Transport, Emissions, and Reactivity (WINTER) campaign; ground-based observations; and the GEOS-Chem chemical transport model to determine the controls on winter [Formula: see text] and [Formula: see text] GEOS-Chem reproduces observed [Formula: see text]-[Formula: see text]-[Formula: see text] particulate concentrations (2.45 µg [Formula: see text]) and composition ([Formula: see text]: 47%; [Formula: see text]: 32%; [Formula: see text]: 21%) during WINTER. Only 18% of [Formula: see text] emissions were regionally oxidized to [Formula: see text] during WINTER, limited by low [H2O2] and [OH]. Relatively acidic fine particulates (pH∼1.3) allow 45% of nitrate to partition to the particle phase. Using GEOS-Chem, we examine the impact of the 58% decrease in winter [Formula: see text] emissions from 2007 to 2015 and find that the H2O2 limitation on [Formula: see text] oxidation weakened, which increased the fraction of [Formula: see text] emissions oxidizing to [Formula: see text] Simultaneously, NOx emissions decreased by 35%, but the modeled [Formula: see text] particle fraction increased as fine particle acidity decreased. These feedbacks resulted in a 40% decrease of modeled [[Formula: see text]] and no change in [[Formula: see text]], as observed. Wintertime [[Formula: see text]] and [[Formula: see text]] are expected to change slowly between 2015 and 2023, unless [Formula: see text] and NOx emissions decrease faster in the future than in the recent past.

8.
Proc Natl Acad Sci U S A ; 115(9): 2038-2043, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29440409

RESUMO

The chemical complexity of atmospheric organic aerosol (OA) has caused substantial uncertainties in understanding its origins and environmental impacts. Here, we provide constraints on OA origins through compositional characterization with molecular-level details. Our results suggest that secondary OA (SOA) from monoterpene oxidation accounts for approximately half of summertime fine OA in Centreville, AL, a forested area in the southeastern United States influenced by anthropogenic pollution. We find that different chemical processes involving nitrogen oxides, during days and nights, play a central role in determining the mass of monoterpene SOA produced. These findings elucidate the strong anthropogenic-biogenic interaction affecting ambient aerosol in the southeastern United States and point out the importance of reducing anthropogenic emissions, especially under a changing climate, where biogenic emissions will likely keep increasing.


Assuntos
Aerossóis/química , Poluentes Atmosféricos/química , Monoterpenos/química , Estações do Ano , Sudeste dos Estados Unidos , Fatores de Tempo
9.
Environ Sci Technol ; 54(7): 3861-3870, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32154714

RESUMO

Secondary organic aerosol (SOA) accounts for a large fraction of the tropospheric particulate matter. Although SOA production rates and mechanisms have been extensively investigated, loss pathways remain uncertain. Most large-scale chemistry and transport models account for mechanical deposition of SOA but not chemical losses such as photolysis. There is also a paucity of laboratory measurements of SOA photolysis, which limits how well photolytic losses can be modeled. Here, we show, through a combined experimental and modeling approach, that photolytic loss of SOA mass significantly alters SOA budget predictions. Using environmental chamber experiments at variable relative humidity between 0 and 60%, we find that SOA produced from several biogenic volatile organic compounds undergoes photolysis-induced mass loss at rates between 0 and 2.2 ± 0.4% of nitrogen dioxide (NO2) photolysis, equivalent to average atmospheric lifetimes as short as 10 h. We incorporate our photolysis rates into a regional chemical transport model to test the sensitivity of predicted SOA mass concentrations to photolytic losses. The addition of photolysis causes a ∼50% reduction in biogenic SOA loadings over the Amazon, indicating that photolysis exerts a substantial control over the atmospheric SOA lifetime, with a likely dependence upon the SOA molecular composition and thus production mechanisms.


Assuntos
Poluentes Atmosféricos , Compostos Orgânicos Voláteis , Aerossóis , Modelos Químicos , Material Particulado , Fotólise
10.
Environ Sci Technol ; 54(10): 5954-5963, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32294377

RESUMO

Wildfires are an important source of nitrous acid (HONO), a photolabile radical precursor, yet in situ measurements and quantification of primary HONO emissions from open wildfires have been scarce. We present airborne observations of HONO within wildfire plumes sampled during the Western Wildfire Experiment for Cloud chemistry, Aerosol absorption and Nitrogen (WE-CAN) campaign. ΔHONO/ΔCO close to the fire locations ranged from 0.7 to 17 pptv ppbv-1 using a maximum enhancement method, with the median similar to previous observations of temperate forest fire plumes. Measured HONO to NOx enhancement ratios were generally factors of 2, or higher, at early plume ages than previous studies. Enhancement ratios scale with modified combustion efficiency and certain nitrogenous trace gases, which may be useful to estimate HONO release when HONO observations are lacking or plumes have photochemical exposures exceeding an hour as emitted HONO is rapidly photolyzed. We find that HONO photolysis is the dominant contributor to hydrogen oxide radicals (HOx = OH + HO2) in early stage (<3 h) wildfire plume evolution. These results highlight the role of HONO as a major component of reactive nitrogen emissions from wildfires and the main driver of initial photochemical oxidation.


Assuntos
Poluentes Atmosféricos/análise , Incêndios Florestais , Aerossóis , Ácido Nitroso/análise , Fumaça
11.
Proc Natl Acad Sci U S A ; 113(6): 1516-21, 2016 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-26811465

RESUMO

Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part of the Southern Oxidant and Aerosol Study. A large fraction of pONs is highly functionalized, possessing between six and eight oxygen atoms within each carbon number group, and is not the common first generation alkyl nitrates previously reported. Using calibrations for isoprene hydroxynitrates and the measured molecular compositions, we estimate that pONs account for 3% and 8% of total submicrometer organic aerosol mass, on average, during the day and night, respectively. Each of the isoprene- and monoterpenes-derived groups exhibited a strong diel trend consistent with the emission patterns of likely biogenic hydrocarbon precursors. An observationally constrained diel box model can replicate the observed pON assuming that pONs (i) are produced in the gas phase and rapidly establish gas-particle equilibrium and (ii) have a short particle-phase lifetime (∼2-4 h). Such dynamic behavior has significant implications for the production and phase partitioning of pONs, organic aerosol mass, and reactive nitrogen speciation in a forested environment.

12.
J Pediatr Orthop ; 37(1): 23-29, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26134078

RESUMO

BACKGROUND: There is growing concern over the relationship between the severity of pediatric fractures and low vitamin D [25-hydroxyvitaminD (25(OH)D)] status. OBJECTIVE: Compare 25(OH)D levels and lifestyle of children with fractures to nonfracture controls to determine if 25(OH)D levels are associated with fractures and if there is a 25(OH)D fragility fracture threshold. METHODS: Pediatric fracture and nonfracture controls were included. Bone health survey and medical record data were analyzed. Fractures were categorized using the Abbreviated Injury Scale (AIS). AIS 3 fractures were identified as fractures that required surgical intervention. Univariate and multivariable ordinal regression analyses were performed to identify potential risk factors for increased fracture severity. RESULTS: A total of 369 fracture patients and 662 nonfracture controls aged 18 years and younger were included. Both groups' 25(OH)D levels were comparable. 25(OH)D was 27.5±8.9 in the fracture group compared with 27.4±9.1 ng/mL in nonfracture controls (P=0.914). AIS 3 fractures had lower 25(OH)D levels (24.6±9.3 ng/mL) versus AIS 1 and 2 (30.0±10.8 and 28.3±8.4, respectively, P=0.001). Univariate correlations for AIS severity were found with age (P=0.015) and outdoor playtime (P=0.042). Adjusted odds ratios for 25(OH)D levels <12 ng/mL was 55.4 (P=0.037), 25(OH)D between 12 and 20 ng/mL was 6.7 (P=0.039), 25(OH)D between 20 and 30 ng/mL was 2.8 (P=0.208), and 25(OH)D between 30 and 40 was 1.7 (P=0.518). CLINICAL RELEVANCE: Occurrence of a pediatric fracture was not associated with 25(OH)D levels in our study. However, children with lower vitamin D levels were found to be at higher risk for more severe fractures. Early evidence suggests that the target serum level for 25(OH)D should be at least 40 ng/mL in patients less than 18 years of age as the relative risk of more severe fractures increased as 25(OH)D levels decreased <40 ng/mL. LEVEL OF EVIDENCE: Level III.


Assuntos
Fraturas Ósseas/epidemiologia , Deficiência de Vitamina D/epidemiologia , Vitamina D/análogos & derivados , Escala Resumida de Ferimentos , Adolescente , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Fraturas Ósseas/sangue , Humanos , Masculino , Análise Multivariada , Análise de Regressão , Fatores de Risco , Vitamina D/sangue , Deficiência de Vitamina D/sangue
13.
Environ Sci Technol ; 50(18): 9872-80, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27548285

RESUMO

With a large global emission rate and high reactivity, isoprene has a profound effect upon atmospheric chemistry and composition. The atmospheric pathways by which isoprene converts to secondary organic aerosol (SOA) and how anthropogenic pollutants such as nitrogen oxides and sulfur affect this process are subjects of intense research because particles affect Earth's climate and local air quality. In the absence of both nitrogen oxides and reactive aqueous seed particles, we measure SOA mass yields from isoprene photochemical oxidation of up to 15%, which are factors of 2 or more higher than those typically used in coupled chemistry climate models. SOA yield is initially constant with the addition of increasing amounts of nitric oxide (NO) but then sharply decreases for input concentrations above 50 ppbv. Online measurements of aerosol molecular composition show that the fate of second-generation RO2 radicals is key to understanding the efficient SOA formation and the NOx-dependent yields described here and in the literature. These insights allow for improved quantitative estimates of SOA formation in the preindustrial atmosphere and in biogenic-rich regions with limited anthropogenic impacts and suggest that a more-complex representation of NOx-dependent SOA yields may be important in models.


Assuntos
Aerossóis , Atmosfera/química , Poluentes Atmosféricos , Óxido Nítrico/química , Óxidos de Nitrogênio , Oxirredução
14.
J Phys Chem A ; 120(4): 576-87, 2016 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-26736021

RESUMO

Iodide-based chemical ionization mass spectrometry (CIMS) has been used to detect and measure concentrations of several atmospherically relevant organic and inorganic compounds. The significant electronegativity of iodide and the strong acidity of hydroiodic acid makes electron transfer and proton abstraction essentially negligible, and the soft nature of the adduct formation ionization technique reduces the chances of sample fragmentation. In addition, iodide has a large negative mass defect, which, when combined with the high resolving power of a high resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS), provides good selectivity. In this work, we use quantum chemical methods to calculate the binding energies, enthalpies and free energies for clusters of an iodide ion with a number of atmospherically relevant organic and inorganic compounds. Systematic configurational sampling of the free molecules and clusters was carried out at the B3LYP/6-31G* level, followed by subsequent calculations at the PBE/SDD and DLPNO-CCSD(T)/def2-QZVPP//PBE/aug-cc-pVTZ-PP levels. The binding energies, enthalpies, and free energies thus obtained were then compared to the iodide-based University of Washington HR-ToF-CIMS (UW-CIMS) instrument sensitivities for these molecules. We observed a reasonably linear relationship between the cluster binding enthalpies and logarithmic instrument sensitivities already at the PBE/SDD level, which indicates that relatively simple quantum chemical methods can predict the sensitivity of an iodide-based CIMS instrument toward most molecules. However, higher level calculations were needed to treat some outlier molecules, most notably oxalic acid and methylerythritol. Our calculations also corroborated the recent experimental findings that the molecules that the UW-CIMS detects at maximum sensitivity usually have binding enthalpies to iodide which are higher than about 26 kcal/mol, depending slightly on the level of theory.

15.
Am J Perinatol ; 32(4): 363-70, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25217737

RESUMO

BACKGROUND: Human toll-like receptor 4 (TLR4) is an important receptor in innate immunity, particularly against gram-negative bacterial infection (GNBI). In our study, we evaluated associations of TLR4 single nucleotide polymorphisms (SNPs) with GNBI in Han Chinese neonates. PATIENTS AND METHODS: Polymorphisms in TLR4 were genotyped in 201 neonates with GNBI and 279 gestational age and birth weight-matched controls without GNBI. Polymorphism analyses were applied to allele frequencies of the detected TLR4 SNPs and their associations with various clinical entities, including premature birth and GNBI were assessed. RESULTS: A total of six SNPs with more than 5% frequency were found in several promoter sequences, including rs10759931, rs2737190, rs10116253, rs10983755, rs1927914, and rs10759932. Mutation allele frequencies ranged from 23 to 41%. There were no SNPs with a frequency greater than 5% in exon analyses. Allele G rs2737190 mutations and GGCGGC haplotypes were more frequent among preterm GNBI neonates (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.02-1.71 and OR, 1.89; 95% CI, 1.19-3.00, respectively). No specific alleles or haplotypes were associated with GNBI status among term neonates. CONCLUSION: In this study population of Han Chinese, there was a significant association between an ethnical unique SNP in the TLR4 promoter region and preterm neonatal GNBIs.


Assuntos
Infecções por Bactérias Gram-Negativas/genética , Polimorfismo de Nucleotídeo Único , Receptor 4 Toll-Like/genética , Alelos , Povo Asiático , China , Feminino , Frequência do Gene , Infecções por Bactérias Gram-Negativas/etnologia , Haplótipos , Humanos , Recém-Nascido , Masculino , Mutação , Razão de Chances
16.
Environ Sci Technol ; 48(11): 6309-17, 2014 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-24800638

RESUMO

A high-resolution time-of-flight chemical-ionization mass spectrometer (HR-ToF-CIMS) using Iodide-adducts has been characterized and deployed in several laboratory and field studies to measure a suite of organic and inorganic atmospheric species. The large negative mass defect of Iodide, combined with soft ionization and the high mass-accuracy (<20 ppm) and mass-resolving power (R>5500) of the time-of-flight mass spectrometer, provides an additional degree of separation and allows for the determination of elemental compositions for the vast majority of detected ions. Laboratory characterization reveals Iodide-adduct ionization generally exhibits increasing sensitivity toward more polar or acidic volatile organic compounds. Simultaneous retrieval of a wide range of mass-to-charge ratios (m/Q from 25 to 625 Th) at a high frequency (>1 Hz) provides a comprehensive view of atmospheric oxidative chemistry, particularly when sampling rapidly evolving plumes from fast moving platforms like an aircraft. We present the sampling protocol, detection limits and observations from the first aircraft deployment for an instrument of this type, which took place aboard the NOAA WP-3D aircraft during the Southeast Nexus (SENEX) 2013 field campaign.


Assuntos
Poluentes Atmosféricos/química , Compostos Inorgânicos/química , Iodetos/química , Espectrometria de Massas/métodos , Compostos Orgânicos/química , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Compostos Inorgânicos/análise , Limite de Detecção , Compostos Orgânicos/análise
17.
J Perinat Med ; 42(6): 717-24, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25178903

RESUMO

OBJECTIVE: The objective of this study was to compare the knowledge of mothers of newborns in a neonatal intensive care unit (NICU) and well-baby nursery (WBN) regarding their understanding of term gestation, delivery mode safety, and elective late preterm delivery. METHODS: Mothers of newborns admitted to either an NICU (n=88) or a WBN (n=145) were surveyed (March 2008-September 2010). RESULTS: Of all mothers, regardless of infant location, 7% were unable to define term gestation, 33% were unaware that scheduling delivery at 35-36 weeks is not advisable, and 30% lacked the knowledge that cesareans are not safer than vaginal deliveries. Multivariate regression models show that socioeconomic and demographic factors underlie many knowledge gaps, and surprisingly, models confirmed that the site (NICU versus WBN) of the infant was not a significant factor related to maternal knowledge. CONCLUSION: This study revealed gaps in mothers' understanding of the medical implications of premature delivery even though most mothers knew the correct length of term gestation. Unexpectedly, NICU mothers who had a child with significant illness and who encountered multiple health care providers did not have improved understanding of perinatal risks. We conclude that all women need to be educated on the significance of the mode and the timing of delivery.


Assuntos
Cesárea/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Unidades de Terapia Intensiva Neonatal , Mães/psicologia , Berçários Hospitalares , Nascimento Prematuro/psicologia , Nascimento a Termo/psicologia , Adolescente , Adulto , Estudos Transversais , Coleta de Dados , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Modelos Logísticos , Pessoa de Meia-Idade , Análise Multivariada , Adulto Jovem
18.
J Natl Med Assoc ; 105(2): 166-72, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24079217

RESUMO

OBJECTIVE: To determine in a controlled cohort whether a one-day hospital visitation program will affect long-term student interest in a career in medicine. DESIGN: Historical cohort study using data from alumni survey in fall 2008. SETTING: Two academic hospitals, in collaboration with a community-based educational organization. PARTICIPANTS: A total of 775 motivated, high-achieving eighth-grade students from low-income households throughout New Jersey. The students were enrolled from school year 2000-01 through 2007-08 in a fourteen-month academic enrichment curriculum run by the New Jersey Scholars, Educators, Excellence, Dedication, Success program (NJ SEEDS) at four sites across the state. INTERVENTION: Students from two of the four sites participated in NJ SEEDS Hospital Day, a one-day experiential hospital visit. MAIN OUTCOME MEASURE: The percentage of alumni who stated the intention to pursue a medical degree. RESULTS: Thirty-nine of 175 (22%) survey respondents who were offered a Hospital Day program stated a plan to pursue a medical degree, compared with 42 of 288 (15%) respondents not offered a Hospital Day experience (p = .03). Adjusting for gender, race, year of participation, and tutoring by a Hospital Day physician, the factors that significantly increased the likelihood of planning to pursue a medical degree were Hospital Day participation (adjusted odds ratio (OR) 2.0; 95% confidence intervals (CI) 1.2-3.4) and Asian race (adjusted OR 3.6; CI 1.3-10.1). CONCLUSIONS: An interactive hospital-based one-day pipeline program was associated with increased plans to pursue a medical degree among NJ SEEDS students when surveyed one to eight years following participation.


Assuntos
Escolha da Profissão , Pediatria/organização & administração , Pobreza , Avaliação de Programas e Projetos de Saúde/métodos , Instituições Acadêmicas , Estudantes/psicologia , Adolescente , Educação Médica , Escolaridade , Feminino , Humanos , Masculino , New Jersey , Estudos Retrospectivos
20.
Pediatr Cardiol ; 33(1): 60-4, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21861146

RESUMO

This study aimed to assess whether tocolytic fetal exposure to antenatal calcium channel blockers (aCCB) increases the risk for hemodynamically significant patent ductus arteriosus (hsPDA) in extremely low-birth-weight (ELBW) infants. This case-control study investigated ELBW infants (<1,000 g) without cardiac defects in a level 3 neonatal intensive care unit who had survived at least 7 days. Nifedipine was the only aCCB used for this study population. The measurements included the history of aCCB exposure, selected maternal data, hsPDA diagnosis, gestational age at birth, birth weight, mode of delivery, sex, maternal race, location of birth, Apgar scores, and selected neonatal morbidities. The end point of the study was hsPDA, defined as an echocardiographically confirmed PDA with clinical symptoms. A total of 180 infants met the study criteria. The diagnosis was hsPDA for 56% of these patients, 20% of whom had aCCB exposure. Of the infants without hsPDA, 11% had aCCB exposure (p = 0.09). No statistically significant associations were found between aCCB exposure and hsPDA after adjustment for gestational age (odds ratio [OR], 1.5; 95% confidence interval [CI], 0.6-3.7) or for gestational age and cumulative aCCB exposure of 100 mg or more (OR, 2.0; 95% CI, 0.6-6.5). A history of aCCB exposure does not appear to increase hsPDA risk in ELBW infants. Studies using neonatal serum nifedipine concentrations after antenatal exposure should be performed to confirm this conclusion.


Assuntos
Bloqueadores dos Canais de Cálcio/efeitos adversos , Permeabilidade do Canal Arterial/induzido quimicamente , Recém-Nascido de muito Baixo Peso , Nifedipino/efeitos adversos , Complicações Cardiovasculares na Gravidez , Tocólise/efeitos adversos , Estudos de Casos e Controles , Feminino , Humanos , Recém-Nascido , Masculino , Gravidez
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