Seizures and Epilepsy Johnson, Emily L
The Medical clinics of North America
103, Številka:
2
Journal Article
Recenzirano
Epilepsy affects 65 million people worldwide, and is a leading neurologic cause of loss of quality-adjusted life years. The diagnosis of seizures and epilepsy often depends on a careful history, and ...is supported with electroencephalogram and imaging. First-line treatment of epilepsy includes medical management. Antiepileptic drugs must be chosen with the patient's particular comorbidities in mind. Drug-resistant epilepsy cases should be referred to an epilepsy specialist and may be evaluated for additional medications, epilepsy surgery, neurostimulation, or dietary therapy. When caring for women, providers must take into account needs for contraception or pregnancy safety where applicable.
For wind turbines operating in cold weather conditions, ice accretion is an established issue that remains an obstacle in effective turbine operation. While the aerodynamic performance of wind ...turbine blades with ice accretion has received considerable research attention, few studies have investigated the structural impact of blade ice accretion. This work proposes an adaptable projection-based method to superimpose complex ice configurations onto a baseline structure. The proposed approach provides an efficient methodology to include ice accretion in the high-fidelity isogeometric shell analysis of a realistic wind turbine blade. Linear vibration and nonlinear deflection analyses of the blade are performed for various ice configurations to demonstrate the impact of different ice accretion distributions on structural performance. These analyses indicate decreases in the blade natural frequencies and deflection under icing conditions. Such ice-induced changes clearly reveal the need for structural design consideration for turbines operating under icing conditions.
The transcatheter aortic valve replacement (TAVR) has emerged as a minimally invasive alternative to surgical treatments of valvular heart disease. TAVR offers many advantages, however, the safe ...anchoring of the transcatheter heart valve (THV) in the patient’s anatomy is key to a successful procedure. In this paper, we develop and apply a novel immersogeometric fluid–structure interaction (FSI) framework for the modeling and simulation of the TAVR procedure to study the anchoring ability of the THV. To account for physiological realism, methods are proposed to model and couple the main components of the system, including the arterial wall, blood flow, valve leaflets, skirt, and frame. The THV is first crimped and deployed into an idealized ascending aorta. During the FSI simulation, the radial outward force and friction force between the aortic wall and the THV frame are examined over the entire cardiac cycle. The ratio between these two forces is computed and compared with the experimentally estimated coefficient of friction to study the likelihood of valve migration.
•An immersogeometric analysis framework for transcatheter heart valves is proposed.•Components of the transcatheter heart valves are modeled and coupled.•Validation of the proposed structural and fluid mechanics methods is presented.•The framework is applied to the simulation of transcatheter aortic valve replacement.•Static friction is considered to study the risk of migration.
Upwelling is an important source of inorganic nutrients in marine systems, yet little is known about how gradients in upwelling affect primary producers on coral reefs. The Southern Line Islands span ...a natural gradient of inorganic nutrient concentrations across the equatorial upwelling region in the central Pacific. We used this gradient to test the hypothesis that benthic autotroph ecophysiology is enhanced on nutrient-enriched reefs. We measured metabolism and photophysiology of common benthic taxa, including the algae Porolithon, Avrainvillea, and Halimeda, and the corals Pocillopora and Montipora. We found that temperature (27.2-28.7°C) was inversely related to dissolved inorganic nitrogen (0.46-4.63 μM) and surface chlorophyll a concentrations (0.108-0.147 mg m-3), which increased near the equator. Contrary to our prediction, ecophysiology did not consistently track these patterns in all taxa. Though metabolic rates were generally variable, Porolithon and Avrainvillea photosynthesis was highest at the most productive and equatorial island (northernmost). Porolithon photosynthetic rates also generally increased with proximity to the equator. Photophysiology (maximum quantum yield) increased near the equator and was highest at northern islands in all taxa. Photosynthetic pigments also were variable, but chlorophyll a and carotenoids in Avrainvillea and Montipora were highest at the northern islands. Phycobilin pigments of Porolithon responded most consistently across the upwelling gradient, with higher phycoerythrin concentrations closer to the equator. Our findings demonstrate that the effects of in situ nutrient enrichment on benthic autotrophs may be more complex than laboratory experiments indicate. While upwelling is an important feature in some reef ecosystems, ancillary factors may regulate the associated consequences of nutrient enrichment on benthic reef organisms.
OBJECTIVETo compare the proportions of unintended pregnancies, prenatal vitamin or folic acid (PNVF) use, adequate prenatal care visits, and breastfeeding among women with epilepsy (WWE) to women ...without epilepsy (WWoE).
METHODSThe Pregnancy Risk Assessment Monitoring System (PRAMS) is an annual survey of randomly sampled postpartum women administered by the Centers for Disease Control and Prevention. We used PRAMS data from 13 states from 2009 to 2014 to compare the primary outcomes in WWE and WWoE, as well as our secondary outcomes of contraception practices, newborn outcomes, and time to recognition of pregnancy. We adjusted for maternal age, race, ethnicity, and socioeconomic status (SES), and we calculated odds ratios for these outcomes using logistic regression.
RESULTSThis analysis included 73,619 women, of whom 541 (0.7%) reported epilepsy, representing 3,442,128 WWoE and 26,635 WWE through weighted sampling. In WWE, 55% of pregnancies were unintended compared to 48% in WWoE. After adjustment for covariates, epilepsy was not associated with unintended pregnancy or with inadequate prenatal care. WWE were less likely to report breastfeeding but more likely to report daily PNVF use. Newborns of WWE had higher rates of prematurity.
CONCLUSIONSAlthough planning for pregnancy is of utmost importance for WWE, more than half the pregnancies in WWE were unintended. Maternal age and SES differences likely contribute to the higher rates in WWE compared to WWoE. The proportion of women reporting breastfeeding is lower in WWE despite studies indicating the safety of breastfeeding in WWE.
Isogeometric analysis (IGA) has been a particularly impactful development in the realm of Kirchhoff–Love thin-shell analysis because the high-order basis functions employed naturally satisfy the ...requirement of C1 continuity. Still, engineering models of appreciable complexity, such as wind turbine blades, are typically modeled using multiple surface patches and, often, neither rotational continuity nor conforming discretization can be practically obtained at patch interfaces. A penalty approach for coupling adjacent patches is therefore presented. The proposed method imposes both displacement and rotational continuity and is applicable to either smooth or non-smooth interfaces and either matching or non-matching discretization. The penalty formulations require only a single, dimensionless penalty coefficient for both displacement and rotation coupling terms, alleviating the problem-dependent nature of the penalty parameters. Using this coupling methodology, numerous benchmark problems encapsulating a variety of analysis types, geometrical and material properties, and matching and non-matching interfaces are addressed. The coupling methodology produces consistently accurate results throughout all tests. Furthermore, the suggested penalty coefficient of α=103 is shown to be effective for the wide range of problem configurations addressed. Finally, a realistic wind turbine blade model, consisting of 27 patches and 51 coupling interfaces and having a chordwise- and spanwise-variant composite material definition, is subjected to buckling, vibration, and nonlinear deformation analyses using the proposed approach.
Valvular heart disease has recently become an increasing public health concern due to the high prevalence of valve degeneration in aging populations. For patients with severely impacted aortic valves ...that require replacement, catheter-based bioprosthetic valve deployment offers a minimally invasive treatment option that eliminates many of the risks associated with surgical valve replacement. Although recent percutaneous device advancements have incorporated thinner, more flexible biological tissues to streamline safer deployment through catheters, the impact of such tissues in the complex, mechanically demanding, and highly dynamic valvular system remains poorly understood. The present work utilized a validated computational fluid–structure interaction approach to isolate the behavior of thinner, more compliant aortic valve tissues in a physiologically realistic system. This computational study identified and quantified significant leaflet flutter induced by the use of thinner tissues that initiated blood flow disturbances and oscillatory leaflet strains. The aortic flow and valvular dynamics associated with these thinner valvular tissues have not been previously identified and provide essential information that can significantly advance fundamental knowledge about the cardiac system and support future medical device innovation. Considering the risks associated with such observed flutter phenomena, including blood damage and accelerated leaflet deterioration, this study demonstrates the potentially serious impact of introducing thinner, more flexible tissues into the cardiac system.
Mixotrophy is among the most successful nutritional strategies in terrestrial and marine ecosystems. The ability of organisms to supplement primary nutritional modes along continua of autotrophy and ...heterotrophy fosters trophic flexibility that can sustain metabolic demands under variable or stressful conditions. Symbiotic, reef-building corals are among the most broadly distributed and ecologically important mixotrophs, yet we lack a basic understanding of how they modify their use of autotrophy and heterotrophy across gradients of food availability. Here, we evaluate how one coral species, Pocillopora meandrina, supplements autotrophic nutrition through heterotrophy within an archipelago and test whether this pattern holds across species globally. Using stable isotope analysis (δ13C) and satellite-derived estimates of nearshore primary production (chlorophyll-a, as a proxy for food availability), we show that P. meandrina incorporates a greater proportion of carbon via heterotrophy when more food is available across five central Pacific islands. We then show that this pattern is consistent globally using data from 15 coral species across 16 locations spanning the Caribbean Sea and the Indian and Pacific Oceans. Globally, surface chlorophyll-a explains 77% of the variation in coral heterotrophic nutrition, 86% for one genus across 10 islands, and 94% when controlling for coral taxonomy within archipelagos. These results demonstrate, for the first time, that satellite-derived estimates of nearshore primary production provide a globally relevant proxy for resource availability that can explain variation in coral trophic ecology. Thus, our model provides a pivotal step toward resolving the biophysical couplings between mixotrophic organisms and spatial patterns of resource availability in the coastal oceans.
•Variation in primary production can reshape coral trophic ecology across scales•A common coral increased heterotrophy at shallow depths on more productive islands•Corals are more heterotrophic in regions of higher nearshore primary production•Coral persistence may be linked to patterns of oceanic primary production
How mixotrophic corals balance autotrophic and heterotrophic nutrition in relation to food availability is unknown. Fox et al. demonstrate that satellite estimates of nearshore primary production predict the trophic ecology of reef-building corals at regional and global scales. In more productive regions, some corals are consistently more heterotrophic.
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