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Understanding Redox Organic Behavior in Deep Eutectic Solvents: Considerations for Molecular Design
Full text linkElectrolytes based on deep eutectic solvents (DESs) coupled with redox active organic molecules have shown potential as a versatile and energy dense electrochemical energy storage system. However, progress in these systems has been held back by a lack of understanding of the irregular behavior displayed when redox active organic molecules are transitioned from other solvent systems. In this work, the hydrogen bonding characteristics of a series of redox organic molecules were investigated through infrared spectroscopy and molecular modeling. New understanding of these interactions was then used to explain their electrochemical behavior in a DES electrolyte. A model was used to predict the behavior of new derivatives towards the design of an optimized redox organic-DES system. Hydrogen bonding between the redox molecules and the solvent was found to significantly shift the potential of a redox reaction more positive when a hydrogen bond forms at the redox active site. It was predicted that functionalizing a molecule with electron withdrawing groups to lower the electron density of the redox active functional group lowers the strength of the hydrogen bond and thus alleviates the undesirable potential shift. This hypothesis was demonstrated by the addition of nitro groups to fluorenones
Traumatic Ulna Fracture with Plastic Deformation of the Radius in a Skeletally Mature Pregnant Female: A Case Report
Full text linkCase: A 20-year-old pregnant female presented with an ulna fracture after a crush and bending type injury. Anatomic reduction of her ulna was not possible due to plastic deformation of the radius, requiring a corrective osteotomy of the radius. She is now 16 months out from surgery with full painless range of motion and radiographic union. Conclusion: Plastic deformation of forearm fractures in adults is a rare phenomenon. It is possible that the patient’s pregnancy contributed to her injury. Patients with uncommon fracture morphology can make operative intervention more complicated and necessitate additional procedures to achieve optimal motion and alignment
Microstructural, Oxidation, and Mechanical Behavior of NbTi-Based Refractory Alloys with 5 to 10 Pct Co, Cr, and Ni Additions
No full textNbTi-based refractory alloys with additions of Co, Cr, and Ni represent an interesting medium-entropy alloy system with potential for protective oxide film formation, high strength, and ductility. This study investigates the microstructural evolution, oxidation behavior, and mechanical properties of NbTi-based alloys containing 5 to 10 at. pct Co, Cr, and Ni. CALPHAD predictions suggest that this composition range can be heat treated to obtain a predominantly body-centered cubic matrix phase. Mechanical properties, including microhardness, yield strength, maximum strength, and specific strength are evaluated through isothermal compression tests conducted between room temperature and 800 °C. The oxidation kinetics of these alloys are assessed through discontinuous oxidation tests. Parabolic oxidation kinetics were observed for NbTi–10Ni and NbTi–5Co, while linear oxidation kinetics were found for NbTi–10Cr and NbTi–10(CoCrNi). Microstructures and oxide layers are characterized using X-ray diffraction, electron backscatter diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. All alloys exhibit significant mechanical softening between room temperature and 800 °C, with elastic-perfectly plastic flow observed at 800 °C. The addition of 10 pct Cr to NbTi resulted in two BCC phases up to 1050 °C, conflicting with CALPHAD predictions of a single-phase solid solution at this temperature, and resulting in higher flow stress at 800 °C. NbTi–10(CoCrNi) exhibited the lowest flow stress at 800 °C despite having more ‘cocktail effect’ potential and insufficient molar fractions of Co, Cr, or Ni to form a desirable protective oxide film
Grid Fragility, Blackouts, and Control Co-Design Solutions
No full textThe grid is undergoing a large-scale transformation, including a significant reduction of synchronous generators, a high penetration of inverter-based resources and renewables, substantial demand growth, new extra-large loads, aging infrastructure and a concerning vulnerability to contingencies. Some of the recent massive blackouts in Spain/Portugal, Chile and Texas are exposing the fragility of the grid as we know it today. This paper introduces new solutions to stabilize the grid under undesired dynamic interactions and extreme contingencies, with the goal of avoiding cascading failures and blackouts. Using control co-design methodologies, the paper proposes three interdependent categories to improve the reliability and controllability of the grid. The first category, or Flexible inverter-based resources (IBRs), proposes inverter-based generators with inverters that can transition from grid-following mode (for energy production) to grid-forming mode (for grid stability), have some form of fast short-term energy storage, and contain advanced control solutions for grid controllability and IBRs’ coordination. The second category, or Intelligent relays, proposes advanced relays that include under-frequency and under-voltage load-shedding capabilities for emergency operation, with smart sensors and algorithms for automatic contingency prediction, impedance estimation and stability assessment. The third category, “2.5 control” or Wide-area real-time control co-design, adds a layer between the conventional secondary and tertiary control systems. It co-designs the dynamics of the grid in real-time, allocating the previous inertia (“energy”), damping (“control authority”) and load-shedding capabilities across different regions of the grid, according to the dynamic variations and stability needs of each location. These concepts have been recently proposed as part of a new ARPA-E effort, called the GRADIENTS program, opening the door to advanced control co-design opportunities to build the grid of the future
Cystic Fibrosis-Related Neurodegenerative Disease Associated with Tauopathy and Cognitive Decline in Aged Cf Mice
No full textBackground: Highly effective modulator therapies (HEMT) are increasing the lifespan for many people with cystic fibrosis (pwCF), making it necessary to identify and understand CF specific age-related consequences. In this study, we examine the impact of aging on cognitive function and age-related brain pathology in a CF mouse model focusing on phospho-Tau (pTau) pathology. Methods: Cognitive function was measured by novel object recognition and spontaneous alternation behavior tests. Hippocampal neuronal function was assessed by measuring long-term potentiation (LTP) electrophysiology, the synaptic correlate of learning and memory. Tau pathology was assessed by immunohistochemical analyses and western blot assessment of pTau levels in CF mouse brain, as well as human nasal epithelial cells isolated from pwCF. Results: Cognitive function declined progressively with age in Cftr (G542X/G542X) (G542X) mice, a model of CF, compared to wild-type (WT) littermate controls. LTP was also deficient in older G542X mice. Increased pTau was observed by staining and western blot analysis in the hippocampus of aged CF mice. Secondary impacts of tauopathy, including increased microglial uptake of cholesterol and reduced neuronal density were also observed. Lastly, human nasal epithelial cells from pwCF were found to display elevated pTau levels compared to non-CF controls. Conclusions: Aging CF mice develop tauopathy, cognitive decline, LTP impairment, microglial activation, and neurodegeneration that is not experienced by age-matched WT littermates, a condition herein termed cystic fibrosis-related neurodegeneration (CFND). These findings suggest that pwCF may be at risk for tauopathy-related neurodegeneration and cognitive impairment with aging
Perianal Infections Update
No full textPurpose of Review We describe the evaluation, treatment, and disposition of patients presenting with perianal and rectal complaints, specifically focusing on identifying and treating various infectious diseases affecting this area. Risk factors and preventative strategies are also discussed where known. Recent Findings Several professional medical associations, namely the World Society of Emergency Surgery and the American Association for the Surgery of Trauma, recently promulgated new guidelines concerning the diagnosis and management of common infectious rectal disorders [1]. The American College of Radiology also published its criteria for choosing appropriate imaging modalities for anorectal disease [2]. Additionally, new meta-analyses have been published trying to shed light on important controversies regarding the optimal management of perirectal abscess, Fournier’s gangrene, and sepsis. During the recent Mpox outbreak, several case reports of patients with perianal complications have been published. This review discusses appropriate diagnosis and management of perianal infections. Summary We will make the recent evidence that has emerged on diagnosis, imaging, treatment, and disposition of perianal infections available to practitioners, aiming to improve patients’ outcomes. Many sexually transmitted diseases, as well as Mpox, can present with rectal complaints, requiring familiarity on the practitioner’s part for optimal management
A Review of Optical Flow Velocimetry in Fluid Mechanics
No full textOptical flow methods have been developed over the past two decades for application to particle image velocimetry (PIV) images with the goal of acquiring higher resolution measurements of the velocity field than conventional cross-correlation (CC)-based techniques. Numerous optical flow velocimetry (OFV) algorithms have been devised to solve the ill-posed optical flow problem, with various physics-inspired strategies to tailor them to fluid flows. While OFV can be applied to continuous scalar fields, it has demonstrated the most success on images of tracer particles, i.e. traditional planar PIV images. Compared to state-of-the-art CC algorithms, OFV methods have demonstrated an order of magnitude increase in spatial resolution and up to a factor of two improvement in overall accuracy when evaluated on synthetic data, at the cost of increased computational time. The requirements for particle seeding density, inter-frame displacement, and image quality are also more stringent for OFV methods compared to CC. OFV has been applied sparingly in experiments to date, but appears to offer the same advantages demonstrated on synthetic data. At this stage, OFV seems best suited to planar velocity measurements, although extensions to stereoscopic measurements have been demonstrated
Burst Pressure Performance of Multilayer Co-Extruded Polystyrene/Poly (Methyl Methacrylate) Pipes
No full textThis study investigates advancements in multilayer co-extrusion of annular structures, focusing on the mechanical properties of a 129-layer polystyrene (PS)/poly(methyl methacrylate) (PMMA) pipe with 50% PS as a skin layer for proof-of-concept validation. We explore the impact of angular rotation on burst pressure, layer structure, and failure mechanisms, emphasizing the potential of this technique for enhanced mechanical performance through biaxial orientation and the elimination of weld lines. Utilizing high aspect ratio (HAR) multipliers and angular rotation, our findings demonstrate improved layer structure and burst pressure performance at higher velocity ratios, which is the ratio of the linear component of angular velocity to the extrusion throughput velocity. At a velocity of 1.15, the 129-layer PS/PMMA tube exhibits a hoop stress of 10.9 MPa and a burst pressure of 3.9 MPa, achieving about 76% and 90% of the performance metrics of pure PMMA tubes with only 25% PMMA content, respectively. Microscopic examination reveals increased residual stress and biaxial orientation within the layers, contributing to the observed performance enhancements. These insights highlight the effectiveness of angular rotation in achieving high-performance polymeric tubes, presenting a promising approach for optimizing multilayer co-extruded annular structures in fluid transport applications
Experimental Determination of Diffusion Flame Extinction Boundaries Over A PMMA Sphere: The Effect of Sub-Surface Solid Heating
No full textThe SoFIE-GEL (Solid Fuel Ignition and Extinction-Growth and Extinction Limit) microgravity combustion experiment was recently conducted aboard the International Space Station (ISS). In these tests, diffusion flame extinction limits of 4-cm diameter PMMA (polymethacrylate) spheres were determined as a function of forced flows (0.2 to 80 cm/s), oxygen concentrations (13 % to 34 %) and pressure (0.15–1.1 atm). In particular, the effect of sample heat-up is investigated. The sample surface layer is preheated by the ignitor and the diffusion flame itself before the extinction procedure (e.g. flow velocity decrease or increase or oxygen decrease) is implemented. The degree of sample heat-up is inversely related to the gas flame heat loss to the solid which is quantified by embedded thermocouples inside the sample sphere near the flow forward stagnation point. This region controls the flame extinction process. In this paper, the extinction boundary in one atmosphere is presented in a map using oxygen percent and flow velocity (and stagnation flow strain rate) as coordinates. The oxygen-velocity (strain rate) boundary is a truncated U-shaped band when plotted with a log x axis. The data at high flow velocity (80 cm/s) is truncated because of the limitation of the test facility. The boundary contains data with different degrees of sample preheating inside the band. More preheat widens the flammable domain. Two modes of extinction are distinguished: quenching at low flow speeds or small stagnation flow strain rates, stagnation and wake blowoffs at high flow velocities or high flow strain rates. Merging between the two branches occurs at a flow strain rate of 7.5 s−1. The minimum oxygen percentage is slightly \u3c14 %. This long duration, remotely controlled microgravity experiment enables us to study the effect of purely forced flow on the burning of bulk solids, especially in the low velocity regime, not easily achievable in normal gravity. In total, 7 hours of microgravity PMMA burning time is recorded. Several examples from recorded test runs are shown to illustrate the special features of the experiment
A Comprehensive Quality Improvement Program to Improve Intubation Performance in Critical Care Transport
No full textObjective: Advanced airway management is a primary skill critical care transport teams provide. There are several measures of performance for airway management that can be tracked and improved through quality improvement initiatives. The purpose of this project was to improve first-pass intubation success rates and the associated Definitive Airway Sans Hypoxia/Hypotension on First Attempt (DASH-1A) metric—definitive airway without hypoxia or hypotension. Methods: A multiyear quality improvement initiative was undertaken. Best practices from the literature were identified and implemented through the Institute for Healthcare Improvement Model for Improvement using a plan-do-study-act cycle approach. Improvement cycles included airway training in a cadaver laboratory, implementation of an airway checklist, use of high-fidelity airway mannequins with simulation, and difficult airway mannequins that could be used for on-shift training. We prioritized tracking of first-pass intubation success rates with focused communication to the team. Results: There was incremental improvement in first-pass success rates evidenced by the stepwise increase in annual moving averages starting at 59% and progressing to the current annual average at approximately 95%. Similarly, DASH-1A results exhibit similar incremental improvement in the moving annual average year on year, starting at 59% and improving to the current 92% annual average. Conclusion: Our results demonstrate that a dedicated quality improvement project focused on improving airway management, specifically first-pass success and DASH-1A, improved our transport team\u27s performance over time
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