Distortion matrix approach for ultrasound imaging of random scattering media.

Focusing waves inside inhomogeneous media is a fundamental problem for imaging. Spatial variations of wave velocity can strongly distort propagating wave fronts and degrade image quality. Adaptive focusing can compensate for such aberration but is only effective over a restricted field of view. Here, we introduce a full-field approach to wave imaging based on the concept of the distortion matrix. This operator essentially connects any focal point inside the medium with the distortion that a wave front, emitted from that point, experiences due to heterogeneities. A time-reversal analysis of the distortion matrix enables the estimation of the transmission matrix that links each sensor and image voxel. Phase aberrations can then be unscrambled for any point, providing a full-field image of the medium with diffraction-limited resolution. Importantly, this process is particularly efficient in random scattering media, where traditional approaches such as adaptive focusing fail. Here, we first present an experimental proof of concept on a tissue-mimicking phantom and then, apply the method to in vivo imaging of human soft tissues. While introduced here in the context of acoustics, this approach can also be extended to optical microscopy, radar, or seismic imaging.

A mix of functional amino acids and grape polyphenols promotes the growth of piglets, modulates the gut microbiota in vivo and regulates epithelial homeostasis in intestinal organoids.

Weaning is a challenging period for gut health in piglets. Previous studies showed that dietary supplementations with either amino acids or polyphenols promote piglet growth and intestinal functions, when administered separately. Thus, we hypothesized that a combination of amino acids and polyphenols could facilitate the weaning transition. Piglets received during the first two weeks after weaning a diet supplemented or not with a mix of a low dose (0.1%) of functional amino acids (L-arginine, L-leucine, L-valine, L-isoleucine, L-cystine) and 100 ppm of a polyphenol-rich extract from grape seeds and skins. The mix of amino acids and polyphenols improved growth and feed efficiency. These beneficial effects were associated with a lower microbiota diversity and a bloom of Lactobacillaceae in the jejunum content while the abundance of Proteobacteria was reduced in the caecum content. The mix of amino acids and polyphenols also increased the production by the caecum microbiota of short-chain fatty acids (butyrate, propionate) and of metabolites derived from amino acids (branched-chain fatty acids, valerate, putrescine) and from polyphenols (3-phenylpropionate). Experiments in piglet jejunum organoids revealed that the mix of amino acids and polyphenols upregulated the gene expression of epithelial differentiation markers while it reduced the gene expression of proliferation and innate immunity markers. In conclusion, the supplementation of a mix of amino acids and polyphenols is a promising nutritional strategy to manage gut health in piglets through the modulation of the gut microbiota and of the epithelial barrier.

Solid-variant aneurysmal bone cysts in the craniofacial skeleton: the role of genomic analysis.

BACKGROUND: Solid variant aneurysmal bone cysts (SVABCs) are a rare but well-described subtype of ABCs. While classic ABCs are readily identified radiographically, SVABCs lack these characteristic radiographic features and thus have a wide differential diagnosis on presentation (including Ewing sarcoma, Langerhans cell histiocytosis, osteosarcoma, metastasis, and giant cell tumor). Genomic/molecular analyses are often necessary for the diagnosis of SVABCs, with USP6 rearrangements being a characteristic finding. We present two cases in which genomic analysis was critical in the diagnosis of SVABCs and revealed unique gene fusions that may provide insight into SVABC pathogenesis. CASE DESCRIPTIONS: Two 13-year old male children presented to our institution with new mass lesions involving the craniofacial skeleton. Magnetic resonance imaging (MRI) in both cases revealed predominantly solid, avidly enhancing masses, one of the squamous portion of the temporal bone, and the other arising from the sphenopalatine foramen with extension into the ipsilateral maxillary and ethmoid sinuses. Histopathology displayed predominantly solid morphology, and next generation sequencing (NGS) revealed a FAT1-USP6 gene fusion in the temporal lesion, and a MIR22HG-USP6 gene fusion in the maxillofacial lesion, the latter of which was not identified on fluorescence in situ hybridization (FISH). These findings were most consistent with a diagnosis of SVABC in each case. CONCLUSIONS: These two cases highlight novel gene fusions in atypically located SVABCs and emphasize the ability of NGS to more accurately and consistently identify USP6 gene fusions, particularly in SVABCs that may otherwise be indistinguishable from alternative pathologies.

Family-acquired photographs for the evaluation of pediatric head shape via telemedicine: an analysis of photograph quality.

OBJECTIVE: Telemedicine can be an effective tool for the evaluation of the pediatric patient with a cranial deformity, but it increases the reliance of neurosurgical providers on data provided by patients and families. Family-acquired photographs, in particular, can be used to augment the evaluation of pediatric head shape abnormalities via telemedicine, but photographs of sufficient quality are necessary. Here, the authors systematically reviewed the quality and utility of family-acquired photographs for patients referred to their pediatric neurosurgery clinic for telemedicine-based head shape evaluations. METHODS: All telemedicine encounters that were completed for head shape abnormalities at the authors' institution between May 2020 and December 2021 were retrospectively reviewed. Instructions were sent to families prior to each visit with examples of ideal photographs. Three orthogonal views of the patient's head-frontal, lateral, and vertex-were requested. Data were collected regarding demographics, diagnosis, follow-up, and photograph quality. Quality variables included orthogonality of each requested view, appropriate distance, appropriate lighting, presence of distracting elements, and whether hair obscured the head shape. RESULTS: Overall, 565 patients had 892 visits during the study period. A total of 1846 photograph requests were made, and 3335 photographs were received for 829 visits. Of 2676 requested orthogonal views, 1875 (70%) were received. Of these, 1826 (97%) had adequate lighting, 1801 (96%) had appropriate distance, and 1826 (97%) had no distracting features. Hair did not obscure the head shape on the vertex view in 557 visits with orthogonal vertex views (82%). In-person follow-up was requested for further medical evaluation in 40 visits (5%). CONCLUSIONS: The family-acquired photographs in this series demonstrated high rates of adequate lighting and distance, without distracting features. Lack of orthogonality and obscuration of the head shape by hair, however, were more common issues. Family education prior to the visit may improve the quality of family-acquired photographs but requires an investment of time by medical staff. Efforts to further improve photographic quality will facilitate efforts to perform craniometric evaluations through telemedicine visits.

Early experience with targeted therapy as a first-line adjuvant treatment for pediatric low-grade glioma.

OBJECTIVE: Pediatric low-grade gliomas (pLGGs) frequently exhibit dysregulation of the mitogen-activated protein kinase (MAPK) pathway. Targeted therapies, including mutant BRAF inhibitors (dabrafenib) and MEK inhibitors (trametinib), have shown promise in patients in whom conventional chemotherapy has failed. However, few studies have investigated the use of targeted therapy as a first-line treatment for pLGG. Here, the authors reviewed their institutional experience with using a personalized medicine approach to patients with newly diagnosed pLGGs. METHODS: All pediatric patients at the authors' institution who had been treated with dabrafenib or trametinib for pLGG without first receiving conventional chemotherapy or radiation were retrospectively reviewed. Demographic, clinical, and radiological data were collected. RESULTS: Eight patients underwent targeted therapy as a first-line treatment for pLGG. Five patients had a BRAF alteration (1 with a BRAFV600E mutation, 4 with a KIAA1549:BRAF fusion), and 3 patients had an NF1 mutation. One of the 8 patients was initially treated with dabrafenib, and trametinib was added later. Seven patients were initially treated with trametinib; of these, 2 later transitioned to dual therapy, whereas 5 continued with trametinib monotherapy. Six patients (75%) demonstrated a partial response to therapy during their treatment course, whereas stable disease was identified in the remaining 2 patients (25%). One patient experienced mild disease progression after completing a course of trametinib monotherapy, but ultimately stabilized after a period of close observation. Another patient experienced tumor progression while on dabrafenib, but subsequently responded to dual therapy with dabrafenib and trametinib. The most common adverse reactions to targeted therapy were cutaneous toxicity (100%) and diarrhea (50%). CONCLUSIONS: Targeted therapies have the potential to become a standard treatment option for pLGG due to their favorable toxicity profile and oral route of administration. This case series provides preliminary evidence that targeted therapies can induce an early disease response as a first-line adjuvant treatment; however, large-scale studies are required to assess long-term durability and safety.

Genomic sequencing of a pregnancy associated symptomatic meningioma of the diaphragma sellae: a case report.

Pregnancy-associated meningiomas have unique considerations and features regarding their pathophysiology, location, genetic profile, and neurosurgical management. These tumours have been reported to undergo rapid growth during gestation and regression post-partum, implicating a role for female sex hormones in tumour physiology. In addition, these tumours occur at a higher incidence in the skull base compared to sporadic meningiomas in the general population, often impinging neurovascular structures and requiring emergent resection. While the genomics of sporadic meningiomas have been described, there are no reports characterizing the genetic features of those associated with pregnancy. Here we describe a patient diagnosed with a diphragma sellae meningioma early in the third trimester after presenting with rapidly deteriorating vision. At 32 weeks gestation the baby was delivered by caesarean section and the tumour subsequently removed. Genomic profiling of the tumour sample revealed variants of unknown significant (VUS) in six genes, none of which were in canonical meningioma drivers. We describe our surgical approach and discuss the relevant pathology and genomics, as well as medical and surgical management considerations of meningiomas in pregnancy.

Juvenile myelomonocytic leukemia presenting in an infant with a subdural hematoma.

BACKGROUND: Juvenile myelomonocytic leukemia (JMML) is a rare childhood hematopoietic disorder typically presenting with hepatosplenomegaly, lymphadenopathy, pallor, fever, and cutaneous findings. The authors report the first case, to our knowledge, of JMML presenting in a pediatric patient with a subdural hematoma. CASE DESCRIPTION: A 7-month old male with recurrent respiratory infections and a low-grade fever presented with a full fontanelle and an increasing head circumference and was found to have chronic bilateral subdural collections. Abusive head trauma, infectious, and coagulopathy workups were unremarkable, and the patient underwent bilateral burr holes for evacuation of the subdural collections. The postoperative course was complicated by the development of thrombocytopenia, anemia, and an acute subdural hemorrhage which required evacuation. Cytologic analysis of the subdural fluid demonstrated atypical cells, which prompted flow cytometric analysis, a bone marrow biopsy, and ultimately a diagnosis of JMML. Following chemotherapy, the patient's counts improved, and he subsequently underwent a hematopoietic stem cell transplant. CONCLUSION: Subdural collections may rarely represent the first presenting sign of hematologic malignancies. In patients with a history of recurrent infections and a negative workup for abusive head trauma, clinicians should include neoplastic etiologies in the differential for chronic subdural collections and have a low threshold for fluid analysis.

Postnatal diagnosis of single-suture craniosynostosis with cranial ultrasound: a systematic review.

INTRODUCTION: The optimal protocol for diagnostic workup of craniosynostosis and the role of specific imaging modalities remain controversial. Skull X-rays and 3-dimensional head CTs are options when physical exam is equivocal but involve ionizing radiation. Ultrasound has emerged as an alternative modality for visualization of cranial sutures, but its use is not widespread. METHODS: The authors performed a systematic review of the literature on the use of ultrasound for the diagnosis of craniosynostosis. RESULTS: A total of 12 studies involving 1062 patients were included. Overall, 300 patients (28.2%) were diagnosed with craniosynostosis. A total of 369 (34.7%) patients had their diagnosis (craniosynostosis vs. patent sutures) confirmed with another imaging modality in addition to ultrasound. Among studies, the specificity of ultrasound ranged from 86 to 100%, and the sensitivity from 71 to 100%. CONCLUSIONS: Ultrasonography of cranial sutures is a feasible and accurate tool for the diagnosis of single-suture craniosynostosis when physical exam findings are insufficient. Although technical aspects of ultrasonography and its interpretation have an associated learning curve, ultrasound can achieve high sensitivity and specificity among patients with suspected craniosynostosis.

Are American Indian/Alaska Native Adolescent Health Behaviors Different? A Review of AI/AN Youth Involved in Native STAND Curriculum, 2014-2017 United States.

OBJECTIVES: To explore health behavior profiles of AI/AN youth involved in native students together against negative decisions (STAND), a national culture-based curriculum. METHODS: We analyzed data from 1236 surveys conducted among AI/AN youth at 40 native STAND implementation sites located in 16 states throughout the US from 2014 to 2017. Health profiles included demographics, sexual orientation, sexual activity, STI testing, cigarette use, and suicide attempts in the past 12-months. We used t-tests and chi square tests of independence to compare risk behavior prevalence among the sample. RESULTS: Health behavior profiles of AI/AN youth indicate that 45.6% of youth did not use condoms the last time they had sex, and 82.7% have never been tested for STIs. Differences in cigarette smoking were observed in questioning youth (questioning: 80.3%, straight/heterosexual: 63.8%, LGBTQ2S + : 49.9%, p = 0.03). CONCLUSIONS FOR PRACTICE: Health behaviors related to sex, substance, violence and self-harm, are at least as common for AI/AN youth as those observed in other US teens. Future research should consider similarities and differences in health profiles of AI/AN youth when designing interventions that affect them. Further, our findings underscore the need for culturally-relevant curricula like native STAND, not because their health behavior is different, but because their socio-ecologic environment is different.

Unrestrained markerless trait stacking in Nannochloropsis gaditana through combined genome editing and marker recycling technologies.

Robust molecular tool kits in model and industrial microalgae are key to efficient targeted manipulation of endogenous and foreign genes in the nuclear genome for basic research and, as importantly, for the development of algal strains to produce renewable products such as biofuels. While Cas9-mediated gene knockout has been demonstrated in a small number of algal species with varying efficiency, the ability to stack traits or generate knockout mutations in two or more loci are often severely limited by selectable agent availability. This poses a critical hurdle in developing production strains, which require stacking of multiple traits, or in probing functionally redundant gene families. Here, we combine Cas9 genome editing with an inducible Cre recombinase in the industrial alga Nannochloropsis gaditana to generate a strain, NgCas9+Cre+, in which the potentially unlimited stacking of knockouts and addition of new genes is readily achievable. Cre-mediated marker recycling is first demonstrated in the removal of the selectable marker and GFP reporter transgenes associated with the Cas9/Cre construct in NgCas9+Cre+ Next, we show the proof-of-concept generation of a markerless knockout in a gene encoding an acyl-CoA oxidase (Aco1), as well as the markerless recapitulation of a 2-kb insert in the ZnCys gene 5'-UTR, which results in a doubling of wild-type lipid productivity. Finally, through an industrially oriented process, we generate mutants that exhibit up to ∼50% reduction in photosynthetic antennae size by markerless knockout of seven genes in the large light-harvesting complex gene family.

Minimizing the Energy Hole Problem in Wireless Sensor Networks: A Wedge Merging Approach.

The Energy hole problem, a common phenomenon in wireless sensor networks, significantly decreases the lifetime of any deployed network. Some of the popular techniques to minimize such problems are using mobile sinks instead of static sinks, extending the transmission range dynamically, and deploying redundant sensor nodes near the base station/sink. The major drawback to these techniques are that energy holes may still be created at some point due to their static nature of deployment, despite having the overall residual energy very high. In this research work, we adopt a new approach by dividing the whole network into equiangular wedges and merging a wedge with its neighboring wedge dynamically whenever individual residual energy of all member nodes of a wedge fall below a threshold value. We also propose an efficient Head Node (HN) selection scheme to reduce the transmission energy needed for forwarding data packets among Head Nodes. Simulation results show that WEMER, our proposed WEdge MERging based scheme, provides significantly higher lifetime and better energy efficiency compared to state-of-the-art Power-Efficient Gathering in Sensor Information Systems (PEGASIS) and contemporary Concentric Clustering Scheme (CCS), and Multilayer Cluster Designing Algorithm (MCDA).

Installation of Minimal Tetrazines through Silver-Mediated Liebeskind-Srogl Coupling with Arylboronic Acids.

Described is a general method for the installation of a minimal 6-methyltetrazin-3-yl group via the first example of a Ag-mediated Liebeskind-Srogl cross-coupling. The attachment of bioorthogonal tetrazines on complex molecules typically relies on linkers that can negatively impact the physiochemical properties of conjugates. Cross-coupling with arylboronic acids and a new reagent, 3-((p-biphenyl-4-ylmethyl)thio)-6-methyltetrazine (b-Tz), proceeds under mild, PdCl2(dppf)-catalyzed conditions to introduce minimal, linker-free tetrazine functionality. Safety considerations guided our design of b-Tz which can be prepared on decagram scale without handling hydrazine and without forming volatile, high-nitrogen tetrazine byproducts. Replacing conventional Cu(I) salts used in Liebeskind-Srogl cross-coupling with a Ag2O mediator resulted in higher yields across a broad library of aryl and heteroaryl boronic acids and provides improved access to a fluorogenic tetrazine-BODIPY conjugate. A covalent probe for MAGL incorporating 6-methyltetrazinyl functionality was synthesized in high yield and labeled endogenous MAGL in live cells. This new Ag-mediated cross-coupling method using b-Tz is anticipated to find additional applications for directly introducing the tetrazine subunit to complex substrates.

Safety Events in High Risk Prehospital Neonatal Calls.

OBJECTIVE: The objective of this study was to quantify and characterize patient safety events during high-risk neonatal transports in the prehospital setting. METHOD: We conducted a retrospective chart review of all "lights and sirens" ambulance transports of neonates ≤30 days old over a four-year period in a metropolitan area. Each case was independently reviewed for potential patient safety events that may have occurred in clinical assessment and decision making, resuscitation, airway management, fluid or medication administration, procedures performed, and/or equipment used. RESULTS: Twenty-six patients ≤30 days old were transported by ambulance using lights and sirens during the four-year study period. Overall, safety events occurred in 19 patients and severe safety events (potentially causing permanent injury or harm, including death) occurred in ten. The incidence of safety events related to medication administrations was 90% (70% severe), resuscitation 64.7% (47.1% severe), procedures 64.7% (35.3% severe), fluid administration 50% (25% severe), clinical assessment and decision making 50% (30.8% severe), airway management 47.6% (28.6% severe), equipment use 25.5% (10.0% severe), and systems processes 19.2% (7.7% severe). CONCLUSIONS: High-risk neonatal calls are infrequent and prone to a high incidence of serious patient safety events.

Out-of-Hospital Pediatric Patient Safety Events: Results of the CSI Chart Review.

OBJECTIVE: Studies of adult hospital patients have identified medical errors as a significant cause of morbidity and mortality. Little is known about the frequency and nature of pediatric patient safety events in the out-of-hospital setting. We sought to quantify pediatric patient safety events in EMS and identify patient, call, and care characteristics associated with potentially severe events. METHODS: As part of the Children's Safety Initiative -EMS, expert panels independently reviewed charts of pediatric critical ambulance transports in a metropolitan area over a three-year period. Regression models were used to identify factors associated with increased risk of potentially severe safety events. Patient safety events were categorized as: Unintended injury; Near miss; Suboptimal action; Error; or Management complication ("UNSEMs") and their severity and potential preventability were assessed. RESULTS: Overall, 265 of 378 (70.1%) unique charts contained at least one UNSEM, including 146 (32.8%) errors and 199 (44.7%) suboptimal actions. Sixty-one UNSEMs were categorized as potentially severe (23.3% of UNSEMs) and nearly half (45.3%) were rated entirely preventable. Two factors were associated with heightened risk for a severe UNSEM: (1) age 29 days to 11 months (OR 3.3, 95% CI 1.25-8.68); (2) cases requiring resuscitation (OR 3.1, 95% CI 1.16-8.28). Severe UNSEMs were disproportionately higher among cardiopulmonary arrests (8.5% of cases, 34.4% of severe UNSEMs). CONCLUSIONS: During high-risk out-of-hospital care of pediatric patients, safety events are common, potentially severe, and largely preventable. Infants and those requiring resuscitation are important areas of focus to reduce out-of-hospital pediatric patient safety events.

Factors Associated With Adherence to Nasoalveolar Molding (NAM) by Caregivers of Infants Born With Cleft Lip and Palate.

OBJECTIVE: Identify factors associated with adherence to nasoalveolar molding (NAM) therapy. DESIGN: Retrospective case-control study. SETTING: Tertiary referral center. PATIENTS, PARTICIPANTS: Infants with cleft lip, with or without cleft palate, referred for NAM. One hundred thirty-five patients met criteria. MAIN OUTCOME MEASURE(S): Adherence to NAM therapy, defined as continuous use of the appliance and attendance of NAM adjustment visits. RESULTS: Female sex (OR = 2.85, 95% CI 1.21-6.74), bilateral cleft (OR = 2.88, 95% CI 1.29-6.46), and travel distance (OR = 1.01, 95% CI 1.00-1.01) were independent predictors of nonadherence. Bilateral clefts (OR = 8.35, 95% CI 2.72-25.64) and public-payer insurance (OR = 3.67, 95% CI 1.13-11.91) for male patients were significantly associated with nonadherence, in our sex-stratified multivariate model. The majority of the families (58%) had public health insurance. Males comprised 77.0% of the cohort. CONCLUSIONS: NAM treatment adherence is impaired by bilateral clefts, female sex, increased travel distance, and public insurance. Further studies are warranted to investigate how these factors affect adherence, and to develop interventions to improve adherence in families at risk due to economic or psychosocial barriers.

Computationally guided discovery of a reactive, hydrophilic trans-5-oxocene dienophile for bioorthogonal labeling.

The use of organic chemistry principles and prediction techniques has enabled the development of new bioorthogonal reactions. As this "toolbox" expands to include new reaction manifolds and orthogonal reaction pairings, the continued development of existing reactions remains an important objective. This is particularly important in cellular imaging, where non-specific background fluorescence has been linked to the hydrophobicity of the bioorthogonal moiety. Here we report that trans-5-oxocene (oxoTCO) displays enhanced reactivity and hydrophilicity compared to trans-cyclooctene (TCO) in the tetrazine ligation reaction. Aided by ab initio calculations we show that the insertion of a single oxygen atom into the trans-cyclooctene (TCO) ring system is sufficient to impart aqueous solubility and also results in significant rate acceleration by increasing angle strain. We demonstrate the rapid and quantitative cycloaddition of oxoTCO using a water-soluble tetrazine derivative and a protein substrate containing a site-specific genetically encoded tetrazine moiety both in vitro and in vivo. We anticipate that oxoTCO will find use in studies where hydrophilicity and fast bioconjugation kinetics are paramount.

Correction: Computationally guided discovery of a reactive, hydrophilic trans-5-oxocene dienophile for bioorthogonal labeling.

Correction for 'Computationally guided discovery of a reactive, hydrophilic trans-5-oxocene dienophile for bioorthogonal labeling' by William D. Lambert et al., Org. Biomol. Chem., 2017, 15, 6640-6644.

The role of simulation in mixed-methods research: a framework & application to patient safety.

BACKGROUND: Research in patient safety is an important area of health services research and is a national priority. It is challenging to investigate rare occurrences, explore potential causes, and account for the complex, dynamic context of healthcare - yet all are required in patient safety research. Simulation technologies have become widely accepted as education and clinical tools, but have yet to become a standard tool for research. METHODS: We developed a framework for research that integrates accepted patient safety models with mixed-methods research approaches and describe the performance of the framework in a working example of a large National Institutes of Health (NIH)-funded R01 investigation. RESULTS: This worked example of a framework in action, identifies the strengths and limitations of qualitative and quantitative research approaches commonly used in health services research. Each approach builds essential layers of knowledge. We describe how the use of simulation ties these layers of knowledge together and adds new and unique dimensions of knowledge. CONCLUSIONS: A mixed-methods research approach that includes simulation provides a broad multi-dimensional approach to health services and patient safety research.

Emergency Contraception in Mexico: Trends in Knowledge and Ever-Use 2006-2014.

Objectives A package of interventions to introduce emergency contraception (EC) to Mexico was implemented, resulting in the addition of EC to the national family planning guidelines in 2004. We describe EC knowledge and use among women in Mexico over time. Methods We used the 2006, 2009, and 2014 of waves of a nationally representative demographic survey (ENADID). We assessed EC knowledge and usage in women ages 15-29 who are not using permanent methods and tested whether EC knowledge and use is changing over time after controlling for socio-demographic characteristics using logistic regression. Results Our sample included n = 99,223 (population N = 40,234,355) women ages 15-29. Overall, knowledge of EC increased over time: 62% in 2006 to 79% in 2009 to 83% in 2014 (p < 0.001). Among young women who have used contraception (n = 42,883; N = 16,816,701), the proportion that reported EC use increased from 3 to 11% to 29% (p < 0.001). Compared to non-users, women who had ever used EC were more likely to be using no method of contraception (44 vs. 35%) or barrier method (22 vs. 17%). Demographic factors including lower wealth, lower education, indigenous status and rural living are significantly associated with less EC knowledge and use. Stratified multivariate analysis found that demographic disadvantages magnify lower EC use among rural residents compared to non-rural residents. Conclusions for Practice Knowledge and use of EC are growing rapidly in Mexico, but disparities persist in demographically disadvantaged women, particularly those living in rural areas. Women who use EC appear to be at higher risk of unintended pregnancy based on current contraceptive use.

Bringing the ocean into the laboratory to probe the chemical complexity of sea spray aerosol.

The production, size, and chemical composition of sea spray aerosol (SSA) particles strongly depend on seawater chemistry, which is controlled by physical, chemical, and biological processes. Despite decades of studies in marine environments, a direct relationship has yet to be established between ocean biology and the physicochemical properties of SSA. The ability to establish such relationships is hindered by the fact that SSA measurements are typically dominated by overwhelming background aerosol concentrations even in remote marine environments. Herein, we describe a newly developed approach for reproducing the chemical complexity of SSA in a laboratory setting, comprising a unique ocean-atmosphere facility equipped with actual breaking waves. A mesocosm experiment was performed in natural seawater, using controlled phytoplankton and heterotrophic bacteria concentrations, which showed SSA size and chemical mixing state are acutely sensitive to the aerosol production mechanism, as well as to the type of biological species present. The largest reduction in the hygroscopicity of SSA occurred as heterotrophic bacteria concentrations increased, whereas phytoplankton and chlorophyll-a concentrations decreased, directly corresponding to a change in mixing state in the smallest (60-180 nm) size range. Using this newly developed approach to generate realistic SSA, systematic studies can now be performed to advance our fundamental understanding of the impact of ocean biology on SSA chemical mixing state, heterogeneous reactivity, and the resulting climate-relevant properties.