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Can extending time between vital sign checks improve sleep in hematopoietic stem cell transplant patients?
No full textBackground Patients undergoing hematopoietic stem cell transplant (HSCT) experience barriers to quality sleep. Frequent vital sign checks are necessary early posttransplant given risk of complications but can disrupt sleep. This study tested feasibility and acceptability of extending time between checking vitals (EVs) from every 4 to every 6 h to improve sleep. Procedure HSCT patients ages 8–21 years ( N = 50, mean age = 14.06, SD = 3.58) and their caregivers were enrolled 1–2 days prior to transplant, and 40 patients completed the 15‐day study (NCT04106089). Patients wore an actigraph to estimate sleep and provided self‐ and caregiver‐report of sleep. Sleep was observed for nights 0 to +4 posttransplant, and patients were then randomized to EVs either Days +5 to +9 or +10 to +14. Patients were assessed daily for medical eligibility to receive EVs; on days patients were eligible, nightshift nurses ( N = 79) reported EV acceptability. Results Of 200 potential nights for EVs (5 nights x 40 patients), patients were eligible for EVs on 126 nights (63% of eligible nights), and patients received EVs on 116 (92%) of eligible nights. Most patients received EVs ≥3 nights ( n = 26, 65%, median = 3 nights). Most patients (85%), caregivers (80%), and nurses (84%) reported that patients used the additional 2 h during EVs for sleep, with reporters indicating moderate to high acceptability. There was preliminary evidence of efficacy indicated by caregiver‐reported sleep disturbance and actigraphy‐estimated improvements in sleep efficiency during EVs. Conclusion Extending time between vitals checks is highly acceptable to patients, caregivers, and nurses, and may offer a feasible approach to improve sleep in pediatric HSCT
Wearable Devices and Digital Biomarkers for Optimizing Training Tolerances and Athlete Performance: A Case Study of a National Collegiate Athletic Association Division III Soccer Team over a One-Year Period
No full textWearable devices in sports have been used at the professional and higher collegiate levels, but not much research has been conducted at lower collegiate division levels. The objective of this retrospective study was to gather big data using the Catapult wearable technology, develop an algorithm for musculoskeletal modeling, and longitudinally determine the workloads of male college soccer (football) athletes at the Division III (DIII) level over the course of a 12-week season. The results showed that over the course of a season, (1) the average match workload (432 ± 47.7) was 1.5× greater than the average training workload (252.9 ± 23.3) for all positions, (2) the forward position showed the lowest workloads throughout the season, and (3) the highest mean workload was in week 8 (370.1 ± 177.2), while the lowest was in week 4 (219.1 ± 26.4). These results provide the impetus to enable the interoperability of data gathered from wearable devices into data management systems for optimizing performance and health.</jats:p
Standard Uncertainty in Socially Responsible Labeling Schemes: A Product Market Experiment
No full textThis paper investigates standard uncertainty in socially responsible labeling schemes. Admist government incapabilities to alleviate negative externalities, corporate social responsibility has been called upon to assist in this mission. Labeling schemes are meant to allow consumers to identify which products promote social responsibility, but when labels are uncertain in the true amount of negative effect the product\u27s production alleviates, they may perpeturate confusion amongst consumers and lose their effectiveness. We conducted a laboratory product market experiment to observe how the behavior of buyers and sellers changes and how welfare is affected when goods that are labeled to signal the social responsibility of the seller have clear standards or are ambiguous to the impact they have in alleviating a negative externality imposed on third-party participants
A Study of the Significance of Changes in Abortion Incidence in Colorado and Kansas as a Result of the Dobbs v Jackson Women\u27s Health Organization Supreme Court Ruling
No full textWhen the Dobbs v Jackson Supreme Court ruling (DvJ) dismantled Roe v Wade, almost half the U.S. states quickly banned and restricted abortion access. Current studies examine access in restrictive states and its detrimental effects on individuals, specifically those of lower socioeconomic status, when it comes to reaching abortion services. Historically, restrictions on abortion have yet to fully stop their occurrence. The following research hypothesizes that states with protective abortion laws are experiencing substantial increases in abortion incidence, driven by out-of-state residents. Colorado and Kansas, which are almost entirely engulfed by ban-states, have already reported high volumes of nonresident patients seeking abortion. Findings observe statistically significant changes in the average of abortion incidence before and after the Dobbs v Jackson decision and explore demographic shifts in abortion occurrence over time. Understanding the impact of the DvJ decision on protective states is necessary for the sustainabilityof abortion going forward
Mechanism-Informed Design of Complex Nanocrystalline Nickel Alloys for Enhanced Hardness
No full textIn this work, a multifactorial, mechanism-informed approach is used to design a novel class of complex multiphase nanocrystalline Ni-based alloys with excellent microstructural stability and mechanical properties. Nanocrystalline materials present promising candidates for advanced engineering applications due to their unique properties, including high strength due to large amounts of Hall-Petch strengthening, which would benefit critical mechanical applications. However, nanocrystalline systems naturally experience a high driving force for grain growth and must be carefully designed to limit grain boundary motion. Simple model nanocrystalline materials have been successfully stabilized against grain growth, but they are often binary and contain only one or two phases. The mechanisms relating to grain boundary behavior are the primary focus of many of these studies, rather than those which enhance properties beyond the grain boundary/size contribution.In the present system, thermal stability against grain growth is not the primary goal. Instead, it is leveraged to provide significant and stable Hall-Petch strengthening to support enhanced high strength in combination with additional strengthening mechanisms from secondary phases and solutes. Hardness testing and advanced characterization techniques, including scanning transmission electron microscopy, were used to elucidate composition-processing-microstructure-property relationships. The primary objective was to use a mechanism-informed design approach to create a complex nanocrystalline alloy which exhibits high strength and long-term thermal stability against coarsening. Ni - 11 at% W - 3 at% Ta - 2 at% Y (Ni-11W-3Ta-2Y) was designed to form nanoscale precipitates, which aid in maintaining a stable nanocrystalline structure to exploit Hall-Petch hardening and strengthening due to a dispersion hardening effect. Solutes were selected to promote a large amount of solid solution strengthening and to decrease the stacking fault energy of the Ni-based matrix for high temperature strength. This mechanically alloyed metal maintained nanoscale grains following anneals up to 67% Tm for 100 hours due to the formation of grain boundary pinning Y2O3 particles and argon bubbles, and it also exhibited hardness in the range of 6.6 – 9.7 GPa. Hall-Petch strengthening contributes roughly 35 – 40% of the total hardness, and dispersion hardening contribution from Orowan looping around fine ceramic particles constitutes another 30%. In support of this primary aim, two other objectives were introduced. The first was to identify the effects of two important milling parameters on the alloy\u27s microstructure: milling time and environment inside of the milling vial, and the second was to elucidate the roles of individual components based on selective removal or variation of added components in the successful quaternary alloy. Milling time was found to strongly impact the contaminant phase content and distribution in the annealed state as well as the quaternary alloy\u27s microstructural evolution and its bulk properties in a surprising way. Rather than improving homogeneity, an increase in milling time by 50% was found to exacerbate the effects of localized inhomogeneities in deformation and composition. This ultimately led to an uneven distribution of grain boundary pinning phases and the formation of abnormally large grains among normal, nanoscale grains following a long-term anneal. Additionally, the presence of Ar bubbles in an annealed cryomilled alloy was able to be mitigated by loading powders in a vacuum glovebox rather than an Ar-filled glovebox. Direct comparison of the annealed microstructures of these vacuum glovebox samples to those loaded in an Ar-filled glovebox prior to milling revealed that the Y2O3 particle – Ar bubble clusters are more effective at pinning grain boundaries than Y2O3 particles with no Ar bubbles. The strategic creation of four new alloys was found to be effective in highlighting the phase and mechanistic roles of individual components. First, the removal of Y to create the Ni-11W-3Ta ternary alloy, produced highly stable Ta2O5 nanoparticles surrounded by a layer of Ta instead of Y2O3. The Ta2O5 particles were found to be more effective at pinning against grain growth than the Y2O3, resulting in finer grain sizes following both short- and long-term anneals. These particles also enhance the alloy\u27s hardness via a dispersion hardening effect. Meanwhile, in the Y-containing ternary alloys (Ni-11W-2Y and Ni-3Ta-2Y), an uneven distribution of pinning phases was found, giving rise to the growth of abnormally large, unpinned grains following long-term anneals. Here, the inhomogeneous distribution of pinning phases was attributed to the lower total solute content enabling the formation of two different Ni – Y intermetallic phases depending on local depletions or enrichments of W/Ta solute. Similarly, a quaternary alloy enriched in W was also produced using the same process, and it was found to contain non-uniform distributions of secondary phases after annealing, but this was attributed to an exacerbation of inhomogeneities from milling due to the increased powder density, and therefore increased energy input. Despite the observation of an undesirable, non-uniform microstructure and loss of strength in some of the milling parameter and compositional variations, these findings inform future process and alloy design for nanocrystalline materials. They also provide insight into the promise of Ta-based oxides over Y-oxides for improved stability in Ni-11W-3Ta and future alloys. The successful mechanism-informed design of two nanocrystalline alloys which are thermally stable against grain growth and exhibits enhanced hardness provides a framework for design of complex, multiphase nanocrystalline alloys, and the exploration of altered milling parameters and alloy compositions provides further insight into the system\u27s composition-processing-structure-properties relationship. Overall, this project supports the future development of advanced engineering materials through an increasingly well-informed design approach
Performance Benefits of Inline Schooling and Formation Control via Frequency and Amplitude Modulation
No full textWhile investigating the hydrodynamics of fish schools, numerous studies have observed thrust and efficiency benefits for swimmers arranged in various simplistic formations with certain kinematics. Here, we present a series of simulations further investigating the hydrodynamic interactions among hydrofoils which can lead to performance benefits and stable formations.Initially, we look at the performance and stability of inline swimmers. Although two swimmers can experience hydrodynamic benefits and achieve stable formations from schooling interactions alone, we want to establish whether these previous findings persist deeper within a school. Building from this, we then investigate the performance and stability characteristics of the school when swimmers are not in-line, but in a side-by-side formation. The side-by-side foils\u27 interaction results in more complex wake dynamics that downstream swimmers can use to their advantage. Finally, we look at the active control of swimmers via a feedback loop within a school. We present two methods of modulating the thrust and their relative position: frequency and amplitude control. Although both methods of control could be used to alter the swimming formation, the performance benefits differ in their vortex-body interactions. Frequency control leads to cycle-varying interactions between leader and follower due to the changing phase synchrony between the two. Conversely, amplitude-controlled foils maintain a constant phase angle that is independent of the amplitude. We show that by tuning the optimal phase angle to target a specific position, the amplitude-controlled foil maintains a constant, favorable phase difference. This allows the swimmer to take the most advantage of the leader\u27s wake to experience a greater performance benefit. These findings aid in the design of formation control schemes of bio-robots that derive hydrodynamic benefits from schooling interactions.This work was supported by the Office of Naval Research under Program Director Dr.Robert Brizzolara on MURI grant number N00014-22-1-261
Kinetic Modeling of Solid-State Reaction Synthesis of Single Crystals
No full textSingle crystal materials are sought after for their uniform ordered structure and lack of grain boundaries which imparts unique properties to the materials, including mechanical, optical, and electrical. The conventional methods to grow single crystal materials include growth from melt, growth from solution, and growth from vapor, but recently more research has been done on solid-state growth techniques. Solid-state growth is of interest because it presents a more cost effective method to grow smaller scale single crystal materials. One novel method is the formation of pseudo single crystals of compounds with pseudobrookite crystal structures via solid-state reaction from a duplex grain mixture. The pseudo single crystal can be formed from unseeded or seeded powder mixtures. This a more efficient solid-state method and observed growth regimes of some compounds indicate that the final structure can be tuned via templating the powders.The potential use of templates to control the final microstructure can be capitalized upon by creating a simulation to aid in predicting the outcome. A variety of modeling techniques have been used to model the kinetics of solid-state reactions, such as the shrinking core model, cellular automata, and Monte Carlo simulation. These three methods all have drawbacks for their application to predicting the microstructure in a solid-state system. The shrinking core model is limited in its scope due to being based on specific geometry and cellular automata is a robust, but computationally intensive method. Kinetic Monte Carlo is the most common technique used for modeling grain growth, but there have been refinements to this model over time. One notable iteration is the Gillespie algorithm, or stochastic simulation algorithm, developed by Daniel T. Gillespie. This was developed for the stochastic solution to coupled chemical reactions, and has been widely used in chemical and biological modeling. Further refinement of the Gillespie algorithm produced ? -leaping, which speeds up the relatively slow method by incrementing simulation time by a variable ?. This method has not been previously applied to a solid-state system and showed promise that it would be an efficient method that gave control over the starting structures and was not as computationally intensive as previous methods. As such initial testing was focused on ensuring that the model was able to accurately simulate the reaction-diffusion process A + B ? C. A single interface case was simulated where the starting geometry consisted of two regions consisting of purely A and B. The simulation results were evaluated based on the work of Gálfi and Rácz who determined the local rate of production, R (z, t) of C as a function of z and t at late times. The calculated concentration of C at the interface at late times aligns with the results of the simulation results. Similar agreement for the early time were achieved based on the work of Taitelbaum et al. The microstructure was expanded to a checkerboard pattern to explore the effects of certain variables in the system. This included diffusivity rates, product stoichiometry, and different diffusivity rates for the A and B atoms. The results give insight into how one can tune the system, such as speeding up or slowing down the product growth and controlling the location of the product phase. Further geometry was tested by setting the initial microstructure to a top seeded model with alternating vertical strips of A and B atoms. Additionally, this model focused on the condition that the product phase can only grow adjacent to existing product. The time-dependence of the propagating reaction in terms of reactant interdiffusion was studied. Mathematically it was determined that CC ? t5/2. The proportionality was found in the simulation data plot of the concentration of C vs scaled time. The model was determined to be a good representation of the physical system. Additionally, insight was gained into how the growth rate of the system changes with time. The microstructure was adjusted further for the final series of simulations which added grain boundaries between the solid A and B regions. This was influenced by discontinuous dissolution reactions in which a migrating front tracks the evolution of a system from a two-phase structure to a single-phase structure. These grain boundaries allowed for a faster diffusion rate when compared to the bulk. The system was run with two initial settings for the grain boundary: with no atoms and with atoms. For the case of no atoms, the relative concentration of C increased approximately as t3, which was the results of the mathematical analysis. This setting resulted in a lower product production at the seed when compared to the full channel
Predicting the Impact of VOCs in Highly Sensitive Medical Processes Using Kinetic and Equilibrium Modeling
No full textVolatile organic compounds (VOCs) are ubiquitous in indoor air spaces, includingthe most sensitive medical environments. These chemicals are associated with deleterious health effects in humans, including respiratory ailments, "sick building syndrome", and cancer. In Assisted Reproduction Technology (ART) facilities, VOCs have been shown to decrease embryo implantation rates significantly. Still, there is a fundamental literature gap regarding the mechanism of VOC partitioning into cell cultures. To contribute to knowledge in this field, modeling approaches are proposed to quantify the equilibrium partitioning affinities and kinetics of selected VOCs in cell cultures through a multi-phase system with oil overlay, water-based culture media, and cellular matter. As part of a collaborative study with Eastern Virginia Medical School (EVMS), studies have simultaneously been conducted on mouse embryos to qualify and quantify the impacts of VOCs on embryogenesis. GC-MS-measured concentrations from triphasic systems determined that the models provide useful trends that describe partitioning for various VOCs, which each have unique chemical qualities and behaviors. These trends indicate a series of toxicological responses observed in embryo studies conducted with styrene and acetaldehyde, including the alteration of growth rates, decreased cell counts, elevated apoptosis, and elevated stress markers. This work can additionally provide insight into quality control improvement in the life sciences industry, specifically the rapidly emerging field of gene therapy