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Background Sympathetic-mediated vasoconstriction from the superior cervical ganglion (SCG) is a significant contributor to cerebral vasospasm. Inhibition of the SCG has been shown to improve cerebral blood flow and reverse cerebral vasospasm in swine models. We evaluated the efficacy of a novel minimally invasive endovascular approach to target and pharmacologically inhibit the SCG, using a Micro-Infusion Device for transmural drug delivery. Methods Eight SCGs in four Yorkshire swine were surgically identified. After confirming appropriate sympathetic-mediated intracranial vasoconstriction response with SCG stimulation, an endovascular Micro- Infusion Device was used for transmural targeting of the SCG and delivery of 1.5--2 mL of 1% lidocaine-contrast mixture to the perivascular space. Digital subtraction angiography was obtained at: (1) baseline; (2) with SCG stimulation; and (3) after lidocaine delivery to the SCG using the Micro-Infusion Device with concurrent SCG stimulation. Vessel diameters were measured and compared. Results Endovascular transmural delivery of lidocaine to the SCG and carotid perivascular tissue using the Micro-Infusion Device successfully inhibited sympathetic-mediated vasoconstriction response. Measured vessel diameters after lidocaine delivery were comparable to baseline despite SCG stimulation. Conclusion A novel endovascular technique of transmural delivery of lidocaine to the SCG and carotid artery perivascular tissues successfully inhibits the sympathetic input to the cerebral vasculature and modulates sympathetic-mediated cerebral vasospasm. These results suggest promising steps towards translation to potential clinical use for patients suffering from cerebral vasospasm. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO 2) is a precursor of ozone (O 3) and fine particulate matter (PM 2.5) – two pollutants that are above regulatory guidelines in many cities. Bringing urban areas into compliance of these regulatory standards motivates an understanding of the distribution and sources of NO 2 through observations and simulations. The TRACER-AQ campaign, conducted in Houston, Texas, in September 2021, provided a unique opportunity to compare observed NO 2 columns from ground-, airborne-, and satellite-based spectrometers. In this study, we investigate how these observational datasets compare and simulate column NO 2 using WRF–CAMx with fine resolution (444 × 444 m 2) comparable to the airborne column measurements. We compare WRF-simulated meteorology to ground-level monitors and find good agreement. We find that observations from the GEOstationary Coastal and Air Pollution Events (GEO-CAPE) Airborne Simulator (GCAS) instrument were strongly correlated (r2 = 0.79) to observations from Pandora spectrometers with a slight high bias (normalized mean bias (NMB) = 3.4 %). Remote sensing observations from the TROPOspheric Monitoring Instrument (TROPOMI) were generally well correlated with Pandora observations (r2 = 0.73) with a negative bias (NMB = - 22.8 %). We intercompare different versions of TROPOMI data and find similar correlations across three versions but slightly different biases (from - 22.8 % in v2.4.0 to - 18.2 % in the NASA MINDS product). Compared with Pandora observations, the WRF–CAMx simulation had reduced correlation (r2 = 0.34) and a low bias (- 21.2 %) over the entire study region. We find particularly poor agreement between simulated NO 2 columns and GCAS-observed NO 2 columns in downtown Houston, an area of high population and roadway densities. These findings point to a potential underestimate of NO x emissions (NO x = NO + NO 2) from sources associated with the urban core of Houston, such as mobile sources, in the WRF–CAMx simulation driven by the Texas state inventory, and further investigation is recommended. [ABSTRACT FROM AUTHOR]

Supramolecular polymer networks contain non-covalent cross-links that enable access to broadly tunable mechanical properties and stimuli-responsive behaviors; the incorporation of multiple unique non-covalent cross-links within such materials further expands their mechanical responses and functionality. To date, however, the design of such materials has been accomplished through discrete combinations of distinct interaction types in series, limiting materials design logic. Here we introduce the concept of leveraging "nested" supramolecular crosslinks, wherein two distinct types of non-covalent interactions exist in parallel, to control bulk material functions. To demonstrate this concept, we use polymer-linked Pd2L4 metal–organic cage (polyMOC) gels that form hollow metal–organic cage junctions through metal–ligand coordination and can exhibit well-defined host-guest binding within their cavity. In these "nested" supramolecular network junctions, the thermodynamics of host-guest interactions within the junctions affect the metal–ligand interactions that form those junctions, ultimately translating to substantial guest-dependent changes in bulk material properties that could not be achieved in traditional supramolecular networks with multiple interactions in series. Supramolecular polymer networks have unique and useful properties due to the reversible nature of their cross-links. Here, the authors show that when two distinct supramolecular interaction classes exist within a single cross-link, new functions can result. [ABSTRACT FROM AUTHOR]

Energy transition scenarios are characterized by increasing electrification and improving efficiency of energy end uses, rapid decarbonization of the electric power sector, and deployment of carbon dioxide removal (CDR) technologies to offset remaining emissions. Although hydrocarbon fuels typically decline in such scenarios, significant volumes remain in many scenarios even at the time of net-zero emissions. While scenarios rely on different approaches for decarbonizing remaining fuels, the underlying drivers for these differences are unclear. Here we develop several illustrative net-zero systems in a simple structural energy model and show that, for a given set of final energy demands, assumptions about the use of biomass and CO2 sequestration drive key differences in how emissions from remaining fuels are mitigated. Limiting one resource may increase reliance on another, implying that decisions about using or restricting resources in pursuit of net-zero objectives could have significant tradeoffs that will need to be evaluated and managed. Assumptions about the use of biomass and CO2 sequestration drive key differences in how emissions from remaining fuels are mitigated in net-zero energy systems, with potentially significant tradeoffs that will need to be evaluated and managed. [ABSTRACT FROM AUTHOR]

Polymer–protein bioconjugation offers a powerful strategy to alter the physical properties of proteins, and various synthetic polymer compositions and architectures have been investigated for this purpose. Nevertheless, conjugation of molecular bottlebrush polymers (BPs) to proteins remains an unsolved challenge due to the large size of BPs and a general lack of methods to transform the chain ends of BPs into functional groups suitable for bioconjugation. Here, we present a strategy to address this challenge in the context of BPs prepared by "graft-through" ring-opening metathesis polymerization (ROMP), one of the most powerful methods for BP synthesis. Quenching ROMP of PEGylated norbornene macromonomers with an activated enyne terminator facilitates the transformation of the BP Ru alkylidene chain ends into Pd oxidative addition complexes (OACs) for facile bioconjugation. This strategy is shown to be effective for the synthesis of two BP–protein conjugates (albumin and ERG), setting the stage for a new class of BP–protein conjugates for future therapeutic and imaging applications. [ABSTRACT FROM AUTHOR]

How the microaerobic pathogen Campylobacter jejuni establishes its niche and expands in the gut lumen during infection is poorly understood. Using 6-wk-old ferrets as a natural disease model, we examined this aspect of C. jejuni pathogenicity. Unlike mice, which require significant genetic or physiological manipulation to become colonized with C. jejuni, ferrets are readily infected without the need to disarm the immune system or alter the gut microbiota. Disease after C. jejuni infection in ferrets reflects closely how human C. jejuni infection proceeds. Rapid growth of C. jejuni and associated intestinal inflammation was observed within 2 to 3 d of infection. We observed pathophysiological changes that were noted by cryptic hyperplasia through the induction of tissue repair systems, accumulation of undifferentiated amplifying cells on the colon surface, and instability of HIF-1α in colonocytes, which indicated increased epithelial oxygenation. Metabolomic analysis demonstrated that lactate levels in colon content were elevated in infected animals. A C. jejuni mutant lacking lctP, which encodes an L-lactate transporter, was significantly decreased for colonization during infection. Lactate also influences adhesion and invasion by C. jejuni to a colon carcinoma cell line (HCT116). The oxygenation required for expression of lactate transporter (lctP) led to identification of a putative thiol-based redox switch regulator (LctR) that may repress lctP transcription under anaerobic conditions. Our work provides better insights into the pathogenicity of C. jejuni. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is the most widely produced synthetic polymer. By installing chemically cleavable bonds into the backbone of PE, it is possible to produce chemically deconstructable PE derivatives; to date, however, such designs have primarily relied on carbonyl‐ and olefin‐related functional groups. Bifunctional silyl ethers (BSEs; SiR2(OR′2)) could expand the functional scope of PE mimics as they possess strong Si−O bonds and facile chemical tunability. Here, we report BSE‐containing high‐density polyethylene (HDPE)‐like materials synthesized through a one‐pot catalytic ring‐opening metathesis polymerization (ROMP) and hydrogenation sequence. The crystallinity of these materials can be adjusted by varying the BSE concentration or the steric bulk of the Si‐substituents, providing handles to control thermomechanical properties. Two methods for chemical recycling of HDPE mimics are introduced, including a circular approach that leverages acid‐catalyzed Si−O bond exchange with 1‐propanol. Additionally, despite the fact that the starting HDPE mimics were synthesized by chain‐growth polymerization (ROMP), we show that it is possible to recover the molar mass and dispersity of recycled HDPE products using step‐growth Si−O bond formation or exchange, generating high molecular weight recycled HDPE products with mechanical properties similar to commercial HDPE. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is the most widely produced synthetic polymer. By installing chemically cleavable bonds into the backbone of PE, it is possible to produce chemically deconstructable PE derivatives; to date, however, such designs have primarily relied on carbonyl‐ and olefin‐related functional groups. Bifunctional silyl ethers (BSEs; SiR2(OR′2)) could expand the functional scope of PE mimics as they possess strong Si−O bonds and facile chemical tunability. Here, we report BSE‐containing high‐density polyethylene (HDPE)‐like materials synthesized through a one‐pot catalytic ring‐opening metathesis polymerization (ROMP) and hydrogenation sequence. The crystallinity of these materials can be adjusted by varying the BSE concentration or the steric bulk of the Si‐substituents, providing handles to control thermomechanical properties. Two methods for chemical recycling of HDPE mimics are introduced, including a circular approach that leverages acid‐catalyzed Si−O bond exchange with 1‐propanol. Additionally, despite the fact that the starting HDPE mimics were synthesized by chain‐growth polymerization (ROMP), we show that it is possible to recover the molar mass and dispersity of recycled HDPE products using step‐growth Si−O bond formation or exchange, generating high molecular weight recycled HDPE products with mechanical properties similar to commercial HDPE. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO2) is a precursor of ozone (O3) and fine particulate matter (PM2.5) – two pollutants that are above regulatory guidelines in many cities. Bringing urban areas into compliance of these regulatory standards motivates an understanding of the distribution and sources of NO2 through observations and simulations. The TRACER-AQ campaign, conducted in Houston, TX in September 2021, provided a unique opportunity to compare observed NO2 columns from ground-, airborne-, and satellite-based spectrometers. In this study, we investigate how these observational datasets compare, and simulate column NO2 using WRF-CAMx with fine resolution (444 x 444 m2) comparable to the airborne column measurements. We find that observations from the GEOCAPE Airborne Simulator (GCAS) instrument were strongly correlated (r2=0.80) to observations from Pandora spectrometers with a negligible bias (NMB=0.1 %). Remote-sensing observations from the TROPOMI instrument were generally well correlated with Pandora observations (r2=0.73) with a negative bias (NMB=-22.8 %). We intercompare different versions of TROPOMI data and find similar correlations across three versions but slightly different biases (from -22.8 % in v2.4.0 to -18.2 % in the NASA MINDS product). Compared to Pandora observations, the WRF-CAMx simulation had reduced correlation (r2=0.34) and a low bias (-25.5 %) over the entire study region. We find particularly poor agreement between simulated NO2 columns and GCAS-observed NO2 columns in downtown Houston an area of high population and roadway densities. These findings point to a potential underestimate of vehicle NOX emissions in the WRF-CAMx simulation driven by the Texas state inventory; and further investigation is recommended. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO2) is a precursor of ozone (O3) and fine particulate matter (PM2.5) - two pollutants that are above regulatory guidelines in many cities. Bringing urban areas into compliance of these regulatory standards motivates an understanding of the distribution and sources of NO2 through observations and simulations. The TRACER-AQ campaign, conducted in Houston, TX in September 2021, provided a unique opportunity to compare observed NO2 columns from ground-, airborne-, and satellite-based spectrometers. In this study, we investigate how these observational datasets compare, and simulate column NO2 using WRF-CAMx with fine resolution (444 x 444 m2) comparable to the airborne column measurements. We find that observations from the GEOCAPE Airborne Simulator (GCAS) instrument were strongly correlated (r2=0.80) to observations from Pandora spectrometers with a negligible bias (NMB=0.1%). Remote-sensing observations from the TROPOMI instrument were generally well correlated with Pandora observations (r2=0.73) with a negative bias (NMB=-22.8%). We intercompare different versions of TROPOMI data and find similar correlations across three versions but slightly different biases (from -22.8% in v2.4.0 to -18.2% in the NASA MINDS product). Compared to Pandora observations, the WRF-CAMx simulation had reduced correlation (r2=0.34) and a low bias (-25.5%) over the entire study region. We find particularly poor agreement between simulated NO2 columns and GCAS-observed NO2 columns in downtown Houston an area of high population and roadway densities. These findings point to a potential underestimate of vehicle NOX emissions in the WRF-CAMx simulation driven by the Texas state inventory; and further investigation is recommended. [ABSTRACT FROM AUTHOR]

Background: Inaccurate manual organ delineation is one of the high‐risk failure modes in radiation treatment. Numerous automated contour quality assurance (QA) systems have been developed to assess contour acceptability; however, manual inspection of flagged cases is a time‐consuming and challenging process, and can lead to users overlooking the exact error location. Purpose: Our aim is to develop and validate a contour QA system that can effectively detect and visualize subregional contour errors, both qualitatively and quantitatively. Methods/Materials: A novel contour subregion error detection (CSED) system was developed using subregional surface distance discrepancies between manual and deep learning auto‐segmentation (DLAS) contours. A validation study was conducted using a head and neck public dataset containing 339 cases and evaluated according to knowledge‐based pass criteria derived from a clinical training dataset of 60 cases. A blind qualitative evaluation was conducted, comparing the results from the CSED system with manual labels. Subsequently, the CSED‐flagged cases were re‐examined by a radiation oncologist. Results: The CSED system could visualize the diverse types of subregional contour errors qualitatively and quantitatively. In the validation dataset, the CSED system resulted in true positive rates (TPR) of 0.814, 0.800, and 0.771; false positive rates (FPR) of 0.310, 0.267, and 0.298; and accuracies of 0.735, 0.759, and 0.730, for brainstem and left and right parotid contours, respectively. The CSED‐assisted manual review caught 13 brainstem, 19 left parotid, and 21 right parotid contour errors missed by conventional human review. The TPR/FPR/accuracy of the CSED‐assisted manual review improved to 0.836/0.253/0.784, 0.831/0.171/0.830, and 0.808/0.193/0.807 for each structure, respectively. Further, the time savings achieved through CSED‐assisted review improved by 75%, with the time for review taking 24.81 ± 12.84, 26.75 ± 10.41, and 28.71 ± 13.72 s for each structure, respectively. Conclusions: The CSED system enables qualitative and quantitative detection, localization, and visualization of manual segmentation subregional errors utilizing DLAS contours as references. The use of this system has been shown to help reduce the risk of high‐risk failure modes resulting from inaccurate organ segmentation. [ABSTRACT FROM AUTHOR]

Background Recent advances in endovascular devices have allowed access and targeting of perivascular tissues of the peripheral circulation. The perivascular tissues of the cervical and cranial circulations have many important structures of clinical significance, yet the feasibility and safety of such an approach has not been demonstrated. Objective To evaluate the safety of a novel endovascular transmural approach to target the perivascular tissues of the common carotid artery in swine. Methods A micro- infusion device was positioned in the carotid arteries of three Yorkshire pigs (six carotid arteries in total), and each carotid artery was punctured 10 times in the same location to gain access to the perivascular tissues. Digital subtraction angiography was used to evaluate vessel injury or contrast extravasation. MRI and MR angiography were used to evaluate evidence of cerebral ischemia or vessel injury. Postmortem tissue analysis was performed to assess the level of extravascular hematoma and intravascular dissection. Results None of the tested carotid arteries showed evidence of vessel injury (dissection or perforation) or intravascular thrombosis. MRI performed after repeated puncture was negative for neck hematoma and brain ischemia. Post- mortem tissue analysis of the carotid arteries showed mild adventitial staining with blood, but without associated hematoma and without vessel dissection. Conclusion Repeated puncture of the carotid artery to gain access to the perivascular tissues using a novel endovascular transmural approach is safe in a swine model. This represents a novel approach to various tissues in close proximity to the cervical and cranial vasculature. [ABSTRACT FROM AUTHOR]

Background: Atrophy of the rotator cuff is a negative prognostic indicator after rotator cuff repair. Although full-thickness rotator cuff tears accompanied by tendon retraction are commonly associated with decreased muscle cross-sectional area (CSA) on magnetic resonance imaging (MRI), it is unclear whether this is accompanied by histologic atrophy of rotator cuff myofibers. Purpose: To evaluate the effect of supraspinatus tendon retraction and myofiber size on supraspinatus atrophy on MRI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Supraspinatus muscle biopsy specimens were obtained from consecutive patients undergoing arthroscopic shoulder surgery. Rotator cuff tears were classified according to size. Preoperative MRI was used to measure tendon retraction and CSA of the supraspinatus muscle in the Y-shaped view. The occupation ratio of the supraspinatus was calculated by dividing the supraspinatus CSA by the supraspinatus fossa CSA. Muscle biopsy specimens were examined using laminin to quantify myofiber CSA. The association between supraspinatus tear size and measures of histologic and MRI muscle atrophy were compared using standard statistical tests. Multivariable logistic regression analysis was used to identify independent predictors of muscle atrophy on MRI. Results: A total of 38 patients were included: 8 with no tear, 14 with a partial-thickness tear, and 16 with a full-thickness tear. Increasing tear size was associated with greater distance of tendon retraction (P <.001), smaller mean histologic myofiber size (P =.004), lower mean supraspinatus CSA on MRI (P <.001), and lower occupation ratio: 0.73 (control), 0.66 (partial tear), 0.53 (small to medium full-thickness tear), and 0.38 (large to massive full-thickness) (P <.001). On Pearson correlation analysis, tendon retraction demonstrated strong correlation with occupation ratio (–0.725; P <.001) and weak correlation with myofiber size (–0.437; P =.006), while occupation ratio showed moderate correlation with myofiber size (0.593; P <.001). Multivariable linear regression analysis demonstrated that increasing tendon retraction (P <.001), age (P =.034), and smaller histologic myofiber CSA (P =.047) were independently associated with greater supraspinatus atrophy on MRI. Conclusion: Supraspinatus muscle atrophy appreciated on MRI is independently associated with patient age, tendon retraction, and atrophy of the supraspinatus myofibers at the histologic level. [ABSTRACT FROM AUTHOR]

The prediction of large fluctuations in the ground magnetic field (dB/dt) is essential for preventing damage from Geomagnetically Induced Currents. Directly forecasting these fluctuations has proven difficult, but accurately determining the risk of extreme events can allow for the worst of the damage to be prevented. Here we trained Convolutional Neural Network models for eight mid‐latitude magnetometers to predict the probability that dB/dt will exceed the 99th percentile threshold 30–60 min in the future. Two model frameworks were compared, a model trained using solar wind data from the Advanced Composition Explorer (ACE) satellite, and another model trained on both ACE and SuperMAG ground magnetometer data. The models were compared to examine if the addition of current ground magnetometer data significantly improved the forecasts of dB/dt in the future prediction window. A bootstrapping method was employed using a random split of the training and validation data to provide a measure of uncertainty in model predictions. The models were evaluated on the ground truth data during eight geomagnetic storms and a suite of evaluation metrics are presented. The models were also compared to a persistence model to ensure that the model using both datasets did not over‐rely on dB/dt values in making its predictions. Overall, we find that the models using both the solar wind and ground magnetometer data had better metric scores than the solar wind only and persistence models, and was able to capture more spatially localized variations in the dB/dt threshold crossings. Plain Language Summary: The interaction between the Sun and the Earth's magnetic field can cause the magnetic field measured on the Earth's surface to change rapidly. These changes can cause damaging currents to run through critical infrastructure such as power lines. Furthermore, the magnetic field can change a large amount in a small distance, meaning that stations that record the magnetic field can have drastically different readings even if they are located close to one another. We can use machine learning algorithms to forecast the risk of these changes in the magnetic field measured on the ground. Using data from stations that measure the magnetic field in addition to data from satellites in between the Sun and the Earth could improve forecast. Here, we created two different models, one using just the data from in between the Sun and the Earth, and one that also used data from the stations that measure the magnetic field on the Earth's surface, to see how they compare in their ability to perform risk assessments. Key Points: Machine learning based probabilistic predictions can provide risk forecasts of extreme dB/dt events at mid‐latitude magnetometer stationsModels utilizing both solar wind and past ground magnetometer data outperform solar wind only and dB/dt based persistence modelsInput feature analysis shows solar wind velocity and IMF BzGSM ${B}_{z}^{\mathit{GSM}}$ strongly influence model output, demonstrating alignment with current understanding [ABSTRACT FROM AUTHOR]

The discovery of neutrophil subtypes has expanded what is known about neutrophil functions, yet there is still much to learn about the role of these subtypes during bacterial infection. We investigated whether Campylobacter jejuni induced differentiation of human neutrophils into the hypersegmented, CD16hi/CD62Llo subtype. In addition, we investigated whether C. jejuni‐dependent differentiation of this neutrophil subtype induced cancer‐promoting activities of human T cells and colonocytes, which were observed in other studies of hypersegmented, CD16hi/CD62Llo neutrophils. We found that C. jejuni causes a significant shift in human neutrophil populations to the hypersegmented, CD16hi/CD62Llo subtype and that those populations exhibit delayed apoptosis, elevated arginase‐1 expression, and increased reactive oxygen species production. Furthermore, incubation of C. jejuni‐infected neutrophils with human T cells resulted in decreased expression of the ζ‐chain of the TCR, which was restored upon supplementation with exogenous l‐arginine. In addition, incubation of C. jejuni‐infected neutrophils with human colonocytes resulted in increased HIF‐1α stabilization and NF‐κB activation in those colonocytes, which may result in the up‐regulation of protumorigenic genes. [ABSTRACT FROM AUTHOR]

The Tropospheric Monitoring Instrument (TROPOMI) on the Sentinel-5 Precursor (S5P) satellite is a valuable source of information to monitor the NOx emissions that adversely affect air quality. We conduct a series of experiments using a 4×4 km 2 Comprehensive Air Quality Model with Extensions (CAMx) simulation during April–September 2019 in eastern Texas to evaluate the multiple challenges that arise from reconciling the NOx emissions in model simulations with TROPOMI. We find an increase in NO2 (+17 % in urban areas) when transitioning from the TROPOMI NO2 version 1.3 algorithm to the version 2.3.1 algorithm in eastern Texas, with the greatest difference (+25 %) in the city centers and smaller differences (+5 %) in less polluted areas. We find that lightning NOx emissions in the model simulation contribute up to 24 % of the column NO2 in the areas over the Gulf of Mexico and 8% in Texas urban areas. NOx emissions inventories, when using locally resolved inputs, agree with NOx emissions derived from TROPOMI NO2 version 2.3.1 to within 20 % in most circumstances, with a small NOx underestimate in Dallas–Fort Worth (-13 %) and Houston (-20 %). In the vicinity of large power plant plumes (e.g., Martin Lake and Limestone) we find larger disagreements, i.e., the satellite NO2 is consistently smaller by 40 %–60 % than the modeled NO2 , which incorporates measured stack emissions. We find that TROPOMI is having difficulty distinguishing NO2 attributed to power plants from the background NO2 concentrations in Texas – an area with atmospheric conditions that cause short NO2 lifetimes. Second, the NOx/NO2 ratio in the model may be underestimated due to the 4 km grid cell size. To understand ozone formation regimes in the area, we combine NO2 column information with formaldehyde (HCHO) column information. We find modest low biases in the model relative to TROPOMI HCHO, with -9 % underestimate in eastern Texas and -21 % in areas of central Texas with lower biogenic volatile organic compound (VOC) emissions. Ozone formation regimes at the time of the early afternoon overpass are NOx limited almost everywhere in the domain, except along the Houston Ship Channel, near the Dallas/Fort Worth International airport, and in the presence of undiluted power plant plumes. There are likely NOx -saturated ozone formation conditions in the early morning hours that TROPOMI cannot observe and would be well-suited for analysis with NO2 and HCHO from the upcoming TEMPO (Tropospheric Emissions: Monitoring Pollution) mission. This study highlights that TROPOMI measurements offer a valuable means to validate emissions inventories and ozone formation regimes, with important limitations. [ABSTRACT FROM AUTHOR]

The synthesis of novel polysilylethers via entropy-driven ring-opening metathesis polymerization (ED-ROMP) of cyclic bifunctional silyl ether-based monomers is reported. These polymers display good thermal stability and ultra-low Tg (−88 °C). Moreover, they are rapidly deconstructable via the cleavage of the silicon-oxygen linkages with acid or fluoride triggers, and they were partially depolymerizable by the addition of exogenous metathesis catalyst. Analysis of the deconstructed polymer products provided insight into the polymer microstructure, showing that the ED-ROMP process was regiorandom. Altogether, this work offers a new class of deconstructable polymers with a range of potential applications. [ABSTRACT FROM AUTHOR]

Polymer electrolytes are promising candidates for the next generation lithium-ion battery technology. Large scale screening of polymer electrolytes is hindered by the significant cost of molecular dynamics (MD) simulation in amorphous systems: the amorphous structure of polymers requires multiple, repeated sampling to reduce noise and the slow relaxation requires long simulation time for convergence. Here, we accelerate the screening with a multi-task graph neural network that learns from a large amount of noisy, unconverged, short MD data and a small number of converged, long MD data. We achieve accurate predictions of 4 different converged properties and screen a space of 6247 polymers that is orders of magnitude larger than previous computational studies. Further, we extract several design principles for polymer electrolytes and provide an open dataset for the community. Our approach could be applicable to a broad class of material discovery problems that involve the simulation of complex, amorphous materials. Screening polymer electrolytes for batteries is extremely expensive due to the complex structures and slow dynamics. Here the authors develop a machine learning scheme to accelerate the screening and explore a space much larger than past studies. [ABSTRACT FROM AUTHOR]

Transgender and gender diverse (TGD), Black, and Latinx communities have long borne a disproportionate share of the U.S. HIV epidemic, yet these same key demographics are continually underrepresented in national PrEP prescriptions. Black, Latinx, and TGD individuals are also more likely to be uninsured, meaning that a proposed federal program to cover PrEP for people without insurance could provide significant benefit to potential PrEP users from these populations. However, coverage of PrEP costs alone will not end disparities in uptake. This commentary provides additional context and recommendations to maximize effectiveness of a national PrEP program for TGD, Black, and Latinx populations in the US. [ABSTRACT FROM AUTHOR]

The U.S. has the tools to end the HIV epidemic, but progress has stagnated. A major gap in U.S. efforts to address HIV is the under-utilization of medications that can virtually eliminate acquisition of the virus, known as pre-exposure prophylaxis (PrEP). This document proposes a financing and delivery system to unlock broad access to PrEP for those most vulnerable to HIV acquisition and bring an end to the HIV epidemic. [ABSTRACT FROM AUTHOR]

Purpose: This paper demonstrates the clinical feasibility and efficacy of HyperArc VMAT treatments for locally recurrent, locally advanced, or previously irradiated head and neck cancers treated with stereotactic radiotherapy (SRT). Materials/Methods: First, an anthropomorphic SRS head phantom from the MD Anderson's IROC credentialing laboratory containing a 1.9 cm diameter spherical target, including in vivo dosimetry system, was imaged, planned, and irradiated (25 Gy in 1 fraction) using HyperArc VMAT with a 6 MV flattening filter free (FFF) beam. Second, RANDO phantom was imaged, planned, and irradiated (35 Gy in 5 fractions) by generating eight HyperArc VMAT plans (4 right, 4 left neck tumors) at different anatomical locations (C1–C4). Average tumor volume was 21.7 cm3 up to 32.3 cm3. Distance to isocenter from the central marker of the Encompass device down to neck was 25.8 cm up to 28.0 cm and 24.3 cm up to 27.1 cm for left‐ and right‐sided neck tumors, respectively, and 9 cm from both lateral markers defined by the patient protection zone. Third, seven recurrent head and neck cancer patients with 80.3 cm3 tumors on average, and up to 159 cm3, were imaged, planned, and treated with 30–40 Gy in 5 fractions with HyperArc SRT. Plan quality, treatment delivery accuracy, and efficiency are reported herein. Results: Phantom irradiation results met all the compliance requirements set forth by the IROC for HyperArc SRS treatment. For end‐to‐end RANDO phantom tests, a highly conformal target dose distribution with 50% isodose fall‐off within 5 mm from the surface of the target was obtained. Average beam modulation factor, beam‐on‐time, and overall treatment time were 2.9, 2.56 min, and 13.96 min with 99.1% pre‐treatment quality assurance pass rate for the 2%/2 mm gamma criteria, respectively. Immediately adjacent critical structures, such as the spinal cord (maximum, 3.9 Gy and 0.35 cm3 of cord, 3.7 Gy) and skin (maximum, 10.3 Gy and 10 cm3 of skin, 5.7 Gy), were spared. Similar results were found on the patient's HyperArc VMAT plans including highly conformal target coverage, sharp dose fall‐off, and low doses to the adjacent critical organs such as the spinal cord (< 5 Gy). Average perfect pitch couch correction was <1.5 mm and 2° in each direction. Average beam‐on‐time was approximately 3.21 min and treatments were completed within 15 min. Conclusion: For recurrent head and neck SRT treatments, HyperArc VMAT provided highly conformal dose distributions, rapid dose fall‐off, excellent sparing of adjacent critical organs, and highly accurate treatments that could be delivered down to the C4 vertebral level. This could potentially allow for delivery of HyperArc SRT to patients with glomus tumors as well to those who may not tolerate frame‐based SRS treatment. Clinical follow up of these patients is ongoing to confirm the therapeutic benefits of this novel treatment option. [ABSTRACT FROM AUTHOR]

The Tropospheric Monitoring Instrument (TROPOMI) on the Sentinel-5 Precursor (S5P) satellite is a valuable source of information to monitor the NOX emissions that adversely affect air quality. We conduct a series of experiments using a 4 × 4 km2 Comprehensive Air Quality Model with Extensions (CAMx) simulation during April - September 2019 in east Texas to evaluate the multiple challenges that arise in reconciling the NOX emissions in model simulations with TROPOMI. We first compare the TROPOMI NO2 version 1.3 and version 2.3.1 algorithms in east Texas and document that tropospheric vertical column NO2 increases +17% in urban areas, with further increases (~25%) in the city centers and smaller increases (~5%) in less polluted areas. We then demonstrate the importance of having lightning NOX emissions in a model simulation that is compared to satellite observations. Lightning NOX can contribute up 24% of the column NO2 in the areas over the Gulf of Mexico and 8% in Texas urban areas. NOX emissions, when using locally resolved inputs, agree with TROPOMI NO2 version 2.3.1 to within 20% in most circumstances, with a small NOX underestimate in Dallas-Fort Worth (- 13%) and Houston (- 20%). In the vicinity of large power plant plumes (e.g., Martin Lake and Limestone) we find larger disagreements: the satellite consistently underrepresents the NO2 from measured stack emissions by 40 - 60%. We hypothesize that either: 1.) TROPOMI has difficulty capturing narrow point source plumes, 2.) the assumed lifetime to derive the NOX emissions is too long, or 3.) the vertical/horizontal dispersion in the model is too slow. If we assume short effective NO2 lifetimes (<1 hour), there is better agreement between the satellite-derived NOX emissions and the model. To understand ozone formation regimes in the area, we combine NO2 column information with HCHO column information. For HCHO, we find good agreement in far eastern Texas and an underestimate (- 25%) in the areas of central Texas that have less biogenic VOC emissions. Ozone formation regimes at the time of the early afternoon overpass are NOx-limited almost everywhere in the domain except the Baytown section of Houston and in the presence of power plant plumes. There are likely NOx-saturated ozone formation conditions in the early morning hours that TROPOMI cannot observe. Having more in situ measurements of the vertical distribution of NO2 in rural and urban areas, and in the presence of power plant plumes would give us more confidence in our results. [ABSTRACT FROM AUTHOR]

The current U.S. emission control requirements for on-road motor vehicles are driven by the ozone problem in the South Coast Air Basin (SoCAB) in southern California. Based on ozone modeling performed for Air Quality Management Plans (AQMPs), the SoCAB ozone attainment plan requires large (>80%) amounts of emission reductions in oxides of nitrogen (NOx) from current levels with more modest (~40%) controls on Volatile Organic Compounds (VOC). The shelter in place orders in response to the 2020 COVID-19 pandemic resulted in an immediate reduction in emissions, but instead of ozone being reduced, in 2020 the SoCAB saw some of the highest observed ozone levels in decades. We used the abrupt emissions reductions from 2019 to 2020 caused by COVID-19 to conduct a dynamic model evaluation of the Community Multiscale Air Quality (CMAQ) model to evaluate whether the models used to develop ozone control plans can correctly simulate the ozone response to the emissions reductions. Ozone modeling was conducted for three scenarios: 2019 Base, 2020 business-as-usual (i.e., without COVID reductions), and 2020 COVID. We found that modeled ozone changes between 2019 and 2020 were generally consistent with the observed ozone changes. We determined that meteorology played the major role in the increases in ozone between 2019 and 2020; however, the reduction in NOX emissions also caused ozone increases in Los Angeles County and into western San Bernardino County, with more widespread ozone decreases further to the east. [ABSTRACT FROM AUTHOR]

INTRODUCTION: We studied the relationship of acute ischemic stroke (AIS) large-vessel occlusion clot composition with vessel recanalization and preprocedure imaging. SUBJECTS AND METHODS: Individual clots from AIS patients who underwent mechanical thrombectomy (MT) between September 2016 and September 2018 were examined. Clot composition was analyzed histologically through a trichrome staining and image segmentation, and the area occupied by red blood cells (RBCs), fibrin, or mixed composition was quantified. RESULTS: Forty-three patients (65.4 ± 12.7 years, 39% of females) who underwent 92 retrieval passes (mean 2.14, range 1-6) were included in this study. Fibrin (44%) occupied the greatest area, followed by mixed composition (34%) and RBCs (22%). A stent retriever was deployed in 81% of cases, 20 patients (47%) achieved first-pass efficacy (FPE) (thrombolysis in cerebral infarction [TICI] 2b-3 after first pass), 41 (95%) achieved successful revascularization (TICI 2b-3), and 21 (49%) had good outcome (modified Rankin Scale [mRS] ≤2) at 90 days. Hyperdense artery sign (HAS) on initial computed tomography was correlated with mixed clot composition (P = 0.01) and lack of fibrin content (P = 0.03). In the univariate analysis, FPE was associated with RBC clot area, atrial fibrillation, and occlusion location but not with fibrin clot area, mixed clot area, stroke etiology, thrombectomy technique, distal emboli, or 90-day mRS. In the multivariate analysis, FPE was significantly correlated with low RBC clot area (odd ratio = 0.96, confidence interval [0.92.99], P = 0.034) but not with atrial fibrillation or location. CONCLUSION: Our results suggest that HAS is correlated with mixed clot composition and lower fibrin content and that lower RBC clot composition is associated with FPE in patients undergoing MT. [ABSTRACT FROM AUTHOR]

Given its physical characteristics and the range of services that it can provide, energy storage raises unique modeling challenges. This paper summarizes capabilities that operational, planning, and resource-adequacy models that include energy storage should have and surveys gaps in extant models. Existing models that represent energy storage differ in fidelity of representing the balance of the power system and energy-storage applications. Modeling results are sensitive to these differences. The importance of capturing chronology can raise challenges in energy-storage modeling. Some models ‘decouple’ individual operating periods from one another, allowing for natural decomposition and rendering the models relatively computationally tractable. Energy storage complicates such a modeling approach. Improving the representation of the balance of the system can have major effects in capturing energy-storage costs and benefits. [ABSTRACT FROM AUTHOR]

The article presents information related to the prehistoric Kiamichi blade discovered at Kiamichi River and Valley in Arkansas and Oklahoma in 2021 by archeologist Jeremiah R. H. Johnson. It describes the physical characteristics of the type 1 and type 2 variants of the blade with an elliptical cross section with signs of resharpening. It explains the similarities of these Kiamichi with the points of McKean Complex of the High Plains.

Treatment techniques and management guidelines for intracranial aneurysms (IAs) have been continually developing and this rapid development has altered treatment decision-making for clinicians. IAs are treated in one of two ways: surgical treatments such as microsurgical clipping with or without bypass techniques, and endovascular methods such as coiling, balloon- or stent-assisted coiling, or intravascular flow diversion and intrasaccular flow disruption. In certain cases, a single approach may be inadequate in completely resolving the IA and successful treatment requires a combination of microsurgical and endovascular techniques, such as in complex aneurysms. The treatment option should be considered based on factors such as age; past medical history; comorbidities; patient preference; aneurysm characteristics such as location, morphology, and size; and finally the operator's experience. The purpose of this review is to provide practicing neurosurgeons with a summary of the techniques available, and to aid decision-making by highlighting ideal or less ideal cases for a given technique. Next, we illustrate the evolution of techniques to overcome the shortfalls of preceding techniques. At the outset, we emphasize that this decision-making process is dynamic and will be directed by current best scientific evidence, and future technological advances. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Proper blood flow is essential for the maintenance of homeostasis for the human cerebrum. The dural venous sinuses comprise the dominant cerebral venous outflow path. Understanding the spatial configuration of the dural venous sinuses can provide valuable insight into several pathological conditions. Previously, only two-dimensional or cadaveric data have been used to understand cerebral outflow. For the first time, we applied three-dimensional rotational venography (3D-RV) to study and provide detailed quantitative morphological measurements of the terminal cerebral venous sinus system in several pathological states. SUBJECTS AND METHODS: Patients who underwent a 3D-RV procedure were identified by reviewing our local institution's endovascular database. Patients with high-quality angiographic images were selected. Eighteen patients were included (37.1 ± 3.8 years). Sinuses were divided into four segments, starting at the torcula and ending at the internal jugular vein. Segment length, 3D displacement, and cross-sectional area were measured. RESULTS: The transverse sinus (60.2 mm) was the longest segment, followed by the sigmoid sinus (55.1 mm). Cross-sectional areas were smallest at the middle of the transverse sinus (21.3 mm2) but increased at the sigmoid sinus (33.5 mm2) and at the jugular bulb (49.7 mm2). The only variation in displacements of venous flow was at the sigmoid-jugular junction, where 55% of cases had lateral displacements versus 45% medial, and 78% superior versus 22% inferior. CONCLUSIONS: We describe the terminal venous sinus system of patients with a variety of diagnoses, detailing segment length, cross-sectional area, and 3D path. [ABSTRACT FROM AUTHOR]