Correction: Ring-opening yields and auto-oxidation rates of the resulting peroxy radicals from OH-oxidation of α-pinene and β-pinene.

[This corrects the article DOI: 10.1039/D2EA00133K.].

Monoterpene Photooxidation in a Continuous-Flow Chamber: SOA Yields and Impacts of Oxidants, NO, and VOC Precursors.

Monoterpene photooxidation plays an important role in secondary organic aerosol (SOA) formation in the atmosphere. The low-volatility products can enhance new particle formation and particle growth and thus influence climate feedback. Here, we present the results of α-pinene and Δ-3-carene photooxidation experiments conducted in continuous-flow mode in an environmental chamber under several reaction conditions.

A Four Carbon Organonitrate as a Significant Product of Secondary Isoprene Chemistry.

Oxidation of isoprene by nitrate radicals (NO) or by hydroxyl radicals (OH) under high NO conditions forms a substantial amount of organonitrates (ONs). ONs impact NO concentrations and consequently ozone formation while also contributing to secondary organic aerosol. Here we show that the ONs with the chemical formula CHNO are a significant fraction of isoprene-derived ONs, based on chamber experiments and ambient measurements from different sites around the globe.

Reducing neonatal phlebotomy blood losses through the accurate calculation of minimum test volume requirements.

Background: Repeated phlebotomy for laboratory diagnostic testing is a known cause of iatrogenic anaemia and in critically ill neonates often leads to blood transfusion being required. This study has developed a spreadsheet clinical decision support tool to allow neonatal staff to determine the true minimum blood volume required to analyse groups of blood tests and modelled its potential benefit compared with the existing system in use.

Methods: The tool calculates the minimum blood volume accounting for novel factors including the current patient haematocrit for plasma/serum samples, instrument minimum test and dead volumes (including those where shared) and sharing of samples within/between laboratory departments.

Quantification of organic aerosol and brown carbon evolution in fresh wildfire plumes.

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.

Resolving ambient organic aerosol formation and aging pathways with simultaneous molecular composition and volatility observations.

Organic aerosol (OA) constitutes a significant fraction of atmospheric fine particle mass. However, the precursors and chemical processes responsible for a majority of OA are rarely conclusively identified. We use online observations of hundreds of simultaneously measured molecular components obtained from 15 laboratory OA formation experiments with constraints on their effective saturation vapor concentrations to attribute the VOC precursors and subsequent chemical pathways giving rise to the vast majority of OA mass measured in two forested regions.

HONO Emissions from Western U.S. Wildfires Provide Dominant Radical Source in Fresh Wildfire Smoke.

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.

Photolysis Controls Atmospheric Budgets of Biogenic Secondary Organic Aerosol.

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.

Anthropogenic enhancements to production of highly oxygenated molecules from autoxidation.

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 (PM). Recent work demonstrates that rapid autoxidation of organic peroxy radicals (RO) formed during VOC oxidation results in highly oxygenated organic molecules (HOM) that efficiently form SOA. As NO emissions decrease, the chemical regime of the atmosphere changes to one in which RO autoxidation becomes increasingly important, potentially increasing PM, while oxidant availability driving RO formation rates simultaneously declines, possibly slowing regional PM formation.

Chemical feedbacks weaken the wintertime response of particulate sulfate and nitrate to emissions reductions over the eastern United States.

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.

Finasteride use during pregnancy and early neonatal outcome: a case report.

The use of antiandrogen drugs such as finasteride during pregnancy may carry the risk of birth defects, especially hypospadias. We report a 39-year-old woman, with 5 weeks unplanned pregnancy, the patient conceived while receiving daily dose of finasteride 2.5 mg for treatment of alopecia.

Airborne Observations of Reactive Inorganic Chlorine and Bromine Species in the Exhaust of Coal-Fired Power Plants.

We present airborne observations of gaseous reactive halogen species (HCl, Cl, ClNO, Br,BrNO, and BrCl), sulfur dioxide (SO), and nonrefractory fine particulate chloride (pCl) and sulfate(pSO) in power plant exhaust. Measurements were conducted during the Wintertime INvestigation of Transport, Emissions, and Reactivity campaign in February-March of 2015 aboard the NCAR-NSF C-130 aircraft. Fifty air mass encounters were identified in which SO levels were elevated ~5 ppb above ambient background levels and in proximity to operational power plants.

Isomerization of Second-Generation Isoprene Peroxy Radicals: Epoxide Formation and Implications for Secondary Organic Aerosol Yields.

We report chamber measurements of secondary organic aerosol (SOA) formation from isoprene photochemical oxidation, in which radical concentrations were systematically varied and the molecular composition of semi- to low-volatility gases and SOA were measured online. Using a detailed chemical kinetics box model, we find that to explain the behavior of low-volatility products and SOA mass yields relative to input HO concentrations, the second-generation dihydroxy hydroperoxy peroxy radical (CHO·) must undergo an intramolecular H-shift with a net forward rate constant of order 0.1 s or higher.

Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms, and organic aerosol.

Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol.

Efficient Isoprene Secondary Organic Aerosol Formation from a Non-IEPOX Pathway.

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.

Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets.

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.

Modeling the Detection of Organic and Inorganic Compounds Using Iodide-Based Chemical Ionization.

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.

Low Vitamin D Levels are Associated With Need for Surgical Correction of Pediatric Fractures.

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.

Hemodynamic monitoring of the critically ill neonate: An eye on the future.

By continuous assessment of dynamic changes in systemic and regional perfusion during transition to extrauterine life and beyond, comprehensive neonatal hemodynamic monitoring creates numerous opportunities for both clinical and research applications. In particular, it has the potential of providing additional details about physiologic interactions among the key hemodynamic factors regulating systemic blood flow and blood flow distribution along with the subtle changes that are frequently transient in nature and would not be detected without such systems in place. The data can then be applied for predictive mathematical modeling and validation of physiologically realistic computer models aiming to identify patient subgroups at higher risk for adverse outcomes and/or predicting the response to a particular perturbation or therapeutic intervention.

Toll-like receptor 4 polymorphisms in gram-negative bacterial infections of Han Chinese neonates.

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.

Delivery-related knowledge of mothers of NICU infants compared with well-baby-nursery infants.

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.