Publications by authors named "Brandon Lopez"

Aircraft observations have revealed ubiquitous new particle formation in the tropical upper troposphere over the Amazon and the Atlantic and Pacific oceans. Although the vapours involved remain unknown, recent satellite observations have revealed surprisingly high night-time isoprene mixing ratios of up to 1 part per billion by volume (ppbv) in the tropical upper troposphere. Here, in experiments performed with the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, we report new particle formation initiated by the reaction of hydroxyl radicals with isoprene at upper-tropospheric temperatures of -30 °C and -50 °C.

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Isoprene affects new particle formation rates in environments and experiments also containing monoterpenes. For the most part, isoprene reduces particle formation rates, but the reason is debated. It is proposed that due to its fast reaction with OH, isoprene may compete with larger monoterpenes for oxidants.

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Highly oxygenated organic molecules (HOMs) are a major source of new particles that affect the Earth's climate. HOM production from the oxidation of volatile organic compounds (VOCs) occurs during both the day and night and can lead to new particle formation (NPF). However, NPF involving organic vapors has been reported much more often during the daytime than during nighttime.

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The main nucleating vapor in the atmosphere is thought to be sulfuric acid (HSO), stabilized by ammonia (NH). However, in marine and polar regions, NH is generally low, and HSO is frequently found together with iodine oxoacids [HIO, i.e.

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Article Synopsis
  • The study investigates how high relative humidity (RH) influences the partitioning of biogenic oxidized organic molecules into secondary organic aerosols (SOA) using real-time measurements in a controlled lab setting.
  • Results show significant increases in SOA mass (45%-85%) as RH rises from low to high levels, with semi-volatile compounds playing a key role in this process.
  • The research explains that higher RH alters the chemical composition of aerosols, shifting toward more volatile species, and emphasizes the critical role of water content in promoting organic aerosol growth.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, China in December 2019 and caused a global pandemic resulting in millions of deaths and tens of millions of patients positive tests. While studies have shown a D614G mutation in the viral spike protein are more transmissible, the effects of this and other mutations on the host response, especially at the cellular level, are yet to be fully elucidated. In this experiment we infected normal human bronchial epithelial (NHBE) cells with the Washington (D614) strain or the New York (G614) strains of SARS-CoV-2.

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Article Synopsis
  • Dimethyl sulfide (DMS) contributes to climate change by affecting cloud formation through its oxidation products, primarily methanesulfonic acid (MSA) and sulfuric acid (HSO), but predicting their levels accurately is difficult.
  • Experiments conducted at CERN's CLOUD chamber showed that lowering the temperature significantly boosts the production of MSA from DMS oxidation, while HSO production remains relatively stable, resulting in a lower HSO/MSA ratio at cold temperatures.
  • The research introduces a new DMS oxidation mechanism that increases MSA production estimates, significantly higher than previous models, revealing MSA's crucial role in the sulfur cycle and its impact on cloud condensation nuclei.
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New particle formation in the upper free troposphere is a major global source of cloud condensation nuclei (CCN). However, the precursor vapours that drive the process are not well understood. With experiments performed under upper tropospheric conditions in the CERN CLOUD chamber, we show that nitric acid, sulfuric acid and ammonia form particles synergistically, at rates that are orders of magnitude faster than those from any two of the three components.

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Objective: Differences in insurer and payer status have been shown to increase patient hospital length of stay (LOS) by delaying the approval of transfer to a rehabilitation facility. The aim of the current study is to determine the impact of the type of insurance provider on postoperative hospital LOS after spine surgery.

Methods: In our single-institution retrospective study, all patients undergoing elective spine surgery between August 2018 and August 2019 as part of an enhanced recovery after surgery (ERAS) protocol were enrolled in a prospectively collected registry.

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Context.—: Emerging evidence shows correlation between the presence of neutralization antibodies (nAbs) and protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently available commercial serology assays lack the ability to specifically identify nAbs.

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Background: The Accreditation Council for Graduate Medical Education establishes minimum case requirements for trainees. In the subspecialty of obstetric anesthesiology, requirements for fellow participation in nonobstetric antenatal procedures pose a particular challenge due to the physical location remote from labor and delivery and frequent last-minute scheduling.

Objectives: In response to this challenge, we implemented an informatics-based notification system, with the aim of increasing fellow participation in nonobstetric antenatal surgeries.

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Postdural puncture headache (PDPH) is a complication of dural puncture. An epidural blood patch (EBP) is the standard treatment; however, when EBP fails, alternative treatments and/or diagnoses must be considered. We present a case of orthostatic headache initially diagnosed as PDPH but likely due to spontaneous intracranial hypotension.

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Introduction: Postdural puncture headache due to accidental dural puncture is a consequence of excessive needle tip overshoot distance after entering the epidural space via a loss of resistance (LOR) technique. We are not aware of any quantitative comparison of the magnitude of needle tip overshoot (distance traveled by the needle tip beyond the point where LOR can be discerned) for the various LOR assessment techniques that are taught. Such a comparison may provide insight into contributing factors of accidental dural puncture and associated postdural puncture headache.

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In this study, feedstock interaction of cow manure and digested sewage sludge on hydrothermal liquefaction (HTL) of loblolly pine (LP) was evaluated. Noncatalytic HTL experiments were performed at reaction temperatures of 250, 275, and 300 °C at a constant reaction time of 30 min. Cyclohexane and acetone were used for biocrude extraction separately.

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Nitrous oxide, long used during labor in Europe, is gaining popularity in the United States. It offers many beneficial attributes, with few drawbacks. Cost, safety, and side effect profiles are favorable.

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Background: Evidence on the analgesic effectiveness of nitrous oxide for labor pain is limited. Even fewer studies have looked at patient satisfaction. Although nitrous oxide appears less effective than neuraxial analgesia, it is unclear whether labor analgesic effectiveness is the most important factor in patient satisfaction.

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