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Primary waves produced by large ships in confined waterways can threaten the sustainability and safety of coastal regions near maritime shipping routes, but the present understanding and predictability of primary wave shallow-water characteristics is hindered by a scarcity of available field observations. This study presents hydrodynamic measurements from 296 primary waves observed in 3.5 to 4.4 m mean water depth throughout four deployments on the channel margins of the Savannah River in Georgia, USA. Ship details and tidally varying waterway parameters are paired with pressure and fluid velocity data to investigate relationships between ship characteristics, waterway conditions, and primary wave magnitudes. Findings show that although larger and faster ships tend to produce larger primary waves, there are inconsistencies among the magnitudes of waves generated by similar ship passages. Additionally, depression prediction equations perform well for most observations, but a small group of "atypically-large" primary waves with depressions exceeding 75 cm are consistently underpredicted and require further investigation. Hydrodynamic, waterway, and ship data are made available in the Supplemental Data. [ABSTRACT FROM AUTHOR]

Deploying Tidal Energy Converters for electricity generation requires prior-knowledge of the potential Annual Energy Production (AEP) at the site, Ideally using a year-long tidal current record at the proposed site to minimize uncertainty. However, such records are often unavailable. Fortunately, using the periodic nature of tidal variability, the International Electrotechnical Commission Technical Specification for tidal energy resource assessment requires AEP calculation using at least 90 days of tidal current records at each turbine location. The sensitivity of AEP to different record durations has not been fully assessed. This is the goal of our study. The study utilized the U.S. tidal energy geodatabase to simulate tidal currents with various lengths, during 100 years of the 21st century. We then consider two frameworks for evaluating AEP: (a) The long-term (months) fixed instrument (FI) measurement at each proposed tidal turbine location, and (b) one FI measurement and short-term (hours) boat-based moving vessel measurements. Under the two scenarios, we examine the AEP assessed from short tidal current records, including how the AEP uncertainties vary spatially and temporally, and how they are associated with various astronomical factors. This helps provide guidance on choosing the appropriate assessment methodologies to reduce the AEP uncertainties and project cost. • The accuracy of annual energy production (AEP) estimation does not necessarily improve with longer tidal current records. • Computed AEP uncertainties are in resonance with relevant astronomical influences. • AEP assessment is improved by following optimal strategies for short record measurements. [ABSTRACT FROM AUTHOR]

The ocean contains a variety of renewable energy resources, little of which has been exploited. Here, we review both tidal range and tidal stream energy, with a focus on the resource, feedbacks, and environmental interactions. The review covers a wide range of timescales of relevance to tidal energy, from fortnightly (spring-neap) and semi-diurnal variability, down to array, and device-scale turbulence. When simulating the regional tidal energy resource, and to assess environmental impacts, it is necessary to account for feedbacks between the tidal array and the resource itself. We critically review various methods for simulating energy extraction, from insights gained through theoretical studies of "tidal fences" in idealized channels, to realistic three-dimensional model studies with complex geometry and arrays of turbines represented by momentum sinks and additional turbulence due to the presence of rotors and support structures. We discuss how variability can be reduced by developing multiple (aggregated) sites with a consideration of the enhanced phase diversity offered by exploiting less energetic tidal currents. This leads to future research questions that have not yet been explored in depth at first-generation tidal sites in relatively sheltered channels (e.g., the interaction of waves with currents). Such enhanced understanding of real sea conditions, including the effects of wind and waves, leads to our other identified primary future research direction—reduced uncertainties in turbulence predictions, including the development of realistic models that simulate the interaction between ambient turbulence and the turbulence resulting from multiple wakes, and changes to system-wide hydrodynamics, water quality, and sedimentation. [ABSTRACT FROM AUTHOR]

To extract mechanistic information of activated processes, we propose to decompose potential energy and free energy differences between configurations into contributions from individual atoms, functional groups, or residues. Decomposition is achieved by calculating the mechanical work associated with the displacements and forces of each atom along a path that connects two states, i.e., following the flow of work. Specifically, we focus on decomposing energy or free energy differences along representative pathways such as minimum energy paths (MEPs) and minimum free energy paths (MFEPs), and a numerical metric is developed to quantify the required accuracy of the reaction path. A statistical mechanical analysis of energy decomposition is also presented to illustrate the generality of this approach. Decomposition along MEP and MFEP is demonstrated on two test cases to illustrate the ability to derive quantitative mechanistic information for different types of activated processes. First, the MEP of alanine dipeptide isomerization in vacuum and the MFEP of isomerization in explicit water is studied. Our analysis shows that carbonyl oxygen and amide hydrogen contribute to most of the energetic cost for isomerization and that explicit water solvation modulates the free energy landscape primarily through hydrogen bonding with these atoms. The second test case concerns the formation of tetrahedral intermediate during a transesterification reaction. Decomposition analysis shows that water molecules not only have strong stabilization effects on the tetrahedral intermediate but also constitute a sizable potential energy barrier due to their significant structural rearrangement during the reaction. We expect that the proposed method can be generally applied to develop mechanistic understanding of catalytic and biocatalytic processes and provide useful insight for strategies of molecular engineering. [ABSTRACT FROM AUTHOR]

Abstract Energy resource classification systems are useful assessment tools that support energy planning and project development, e.g., siting and feasibility studies. They typically establish standard classes of power, a measure of the opportunity for energy resource capture. In this study, we develop wave energy resource classification systems for the US based on wave power (J , kW/m) and its distribution with peak period ( T p , s). These metrics are calculated for 70,386 sites from partitioned bulk wave parameters generated from a validated 30-year WaveWatch III model hindcast. As the operating resonant period bandwidth of a wave energy converter (WEC) technology is an important design characteristic, the dominant period band containing the largest energy content is identified among three peak period band classes. These classification systems, comprised of four power classes and three peak period band classes, are based on the total wave power or the partitioned wave power in the dominant peak period band. They discriminate distinct trends in wave energy resource among five regions within the US, and provide useful information for energy planners, project developers, and technology designers. They also establish a framework for investigating the feasibility of a compatible wave climate (design load) conditions and WEC technology classification system to reduce design and manufacturing costs. Highlights • Classification parameters discriminate distinct trends in US wave climates. • Key attributes classified for energy planning and project development. • Key attributes classified for design and operation of WEC technologies. [ABSTRACT FROM AUTHOR]

This study investigates the role of low-frequency cargo vessel wake to erosion at Bird/Long Island in the Savannah River, Georgia. The island splits the river into the Main Channel that accommodates cargo vessels traveling to the Port of Savannah, and the shallower, sheltered South Channel. Pressure and velocity data from both channels are used to characterize wind waves, tidal currents, and vessel wake. The relevance of each process to erosion is estimated by using hydrodynamic power as a proxy for erosive potential. Instantaneous water level is compared to the elevation of an eroding scarp to identify "scarp-relevant" power contributions, power occurring when the eroding scarp is at least partly submerged and susceptible to erosion. The analysis shows that scarp-relevant power in the Main Channel is dominated by cargo vessel wake (88%), with smaller contributions from tidal currents (5%) and wind waves (7%). Power in the South Channel is also dominated by cargo vessel wake (65%), followed by tidal currents (34%) and wind waves (1%). A follow-up study confirms that low-frequency cargo vessel wake, which produces waves heights up to 2.01 m in the Main Channel, propagates readily around both ends of the island and into the South Channel, where it produces wave heights up to 0.32 m. • Hydrodynamic power of tidal currents, wind waves, and cargo vessel wake was measured at two sites: one exposed, one sheltered. • Hydrodynamic power was used as a proxy for relative contributions to erosion. • Low-frequency cargo vessel wake was the main source of hydrodynamic power at both sites. [ABSTRACT FROM AUTHOR]

Tidal currents are a promising source for future power generation given their periodicity and predictability. Therefore, numerical hydrodynamic models are frequently utilized for resource assessments. However, the relevant scales of the simulations and hence modeling techniques depend on the problem at hand. This paper shows the potential of the grid refinement technique for the assessment of tidal current energy for particular sites given its relatively low computational expense and high accuracy for the regions with the refined resolution. Example applications are described for mapping the tidal resources near two facilities (Portsmouth Naval Shipyard in Maine and Key West Naval Station in Florida) for possible future deployments of Marine Hydro-Kinetic technologies. The grid refinement capability in the coupled ocean-atmosphere-wave-sediment transport modeling system is used to improve the spatial resolution in the regions of interest, and has shown significant advantage over the original simulation results for the tidal power assessment. The numerical simulation results from both the original coarse grids and the refined grids are validated with measured tidal constituents at available locations. This study demonstrates how the enhancement of a model system for a regional tidal energy with grid refinement can assist with the performance of site specific resource assessments with modest computational expense. [ABSTRACT FROM AUTHOR]

Ocean currents represent an alternative source of clean energy given their inherent reliability, persistence and sustainability. The general ocean circulation is characterized by large rotating ocean gyres resulting in rapid ocean currents along the western boundaries because of the Coriolis Effect. The Gulf Stream system is formed by the western boundary current of the North Atlantic Ocean flowing along the east coast of the United States, and is of particular interest as a potential energy resource for the United States. This study presents a national database of ocean current kinetic energy resource derived from seven years of numerical model simulations to help advance awareness and market penetration for ocean current energy. A web based GIS interface is provided for dissemination of the national energy resource data: http://www.oceancurrentpower.gatech.edu/ . The website includes GIS layers of computed monthly and yearly mean ocean current speed and associated power density along the coastlines of the United States, as well as joint and marginal probability histograms for current velocities at a variable horizontal resolution of 4–7 km. Various tools are provided for viewing, identifying, filtering and downloading the data from this website. The Gulf Stream system, especially the Florida Current, concentrates the highest kinetic power density ( > 2000 W / m 2 ). The majority of the kinetic power and its variability are only present in relatively shallow water given the strong correlation with the surface wind stress. The kinetic energy flux in the Florida Current is estimated over 30 years to provide temporal variability of the undisturbed kinetic energy with high statistical significance. Available power of approximately 5 GW associated with the undisturbed natural flow condition from the Gulf Stream system is predicted based on hypothetical turbine parameters. Successful development of renewable energy generation requires further studies to account for more precise technical, economic and environmental constraints. [ABSTRACT FROM AUTHOR]

Increasing energy consumption and decreasing reserves of fossil fuels have led to growing interest in renewable energy from the ocean. Ocean currents are an alternative source of clean energy due to their inherent reliability, persistence and sustainability. General ocean circulations exist in the form of large rotating ocean gyres, and feature extremely rapid current flow in the western boundaries due to the Coriolis effect. The Gulf Stream system is formed by the western boundary current of the North Atlantic Ocean that flows along the east coastline of the United States, and therefore is of particular interest as a potential energy resource for the United States. The theoretical energy balance in the Gulf Stream system is examined using the two-dimensional ocean circulation equations based on the assumptions of the Stommel model for subtropical gyres with the quasi-geostrophic balance between pressure gradient, Coriolis force, wind stress and friction driving the circulation. To represent flow dissipation due to turbines a spatially varying turbine drag coefficient is formulated and a finite difference numerical approach is utilized to obtain an implicit solution of the model. The results show that considering extraction over a region representing the entire Florida Current portion of the Gulf Stream system, the average power dissipated ranges between 4 and 6 GW with a mean around 5.1 GW. This corresponds to an average of approximately 45 TWh/yr. However, if the extraction area approximates the entire portion of the Gulf Stream within 200 miles of the US coastline, the average power dissipated becomes 18.6 GW or 163 TWh/yr. The impact of the localized turbine drag on the hydrodynamics is primarily within the turbine region. The extra drag force from turbines slows down the current velocity and leads to redirection of the Gulf Stream flow. It also results in a sea surface drop in the turbine region. Localized turbine drag significantly reduces residual kinetic energy flux in the circulation. However, its influence on the residual volume flux depends on the area of the turbine region. [ABSTRACT FROM AUTHOR]

Objective To determine the feasibility of administering a diazepam nasal spray formulation (diazepam- NS) to adults with epilepsy during a generalized tonic-clonic seizure or in the postictal period following a tonic-clonic or other seizure type, to assess pharmacokinetics and to assess tolerability. Methods An open-label study was conducted in patients admitted to the epilepsy monitoring unit. Eligible patients received a single dose of diazepam- NS approximating 0.2 mg/kg. Plasma diazepam concentrations were measured serially up to 12 h postdose, and maximum observed plasma concentration (Cmax); time to maximum concentration (Tmax); and the area under the plasma concentration-time curve for time zero to last sampling time (AUC0-12) were estimated and dose-normalized. Pharmacodynamic assessments included Kaplan-Meier analysis to determine the time-to-next seizure. Safety and tolerability were assessed. Results Of the 78 patients who consented, 30 had treatment and pharmacokinetic data. Ten patients were treated during a convulsive tonic-clonic seizure, seven within 5 min following the last clonic jerk, and 13 in the postictal period ≥5 min after a tonic-clonic or following other seizure-types. Diazepam median Tmax was 45 min. Dose-normalized mean Cmax and AUC0-12 values of diazepam were comparable among patients regardless of the timing of diazepam- NS administration in relation to seizure. Of those treated, 65% were seizure-free during the 12-h observation period and 35% had post-dose seizures. Treatment was well tolerated, with no unexpected safety findings: 74% had mild and 25% had moderate adverse events. Nasopharyngeal signs were resolved by 12 h postdose. Significance Diazepam can be delivered in effective therapeutic concentrations by a nasal spray device during the convulsive phase of tonic-clonic seizures or in the postictal periods following tonic-clonic or other seizure types. [ABSTRACT FROM AUTHOR]

The analytical expression for thetrajectory entropy of the overdampedLangevin equation is derived via two approaches. The first route goesthrough the Fokker–Planck equation that governs the propagationof the conditional probability density, while the second method goesthrough the path integral of the Onsager–Machlup action. Theagreement of these two approaches in the continuum limit underscoresthe equivalence between the partial differential equation and thepath integral formulations for stochastic processes in the contextof trajectory entropy. The values obtained using the analytical expressionare also compared with those calculated with numerical solutions forarbitrary time resolutions of the trajectory. Quantitative agreementis clearly observed consistently across different models as the timeinterval between snapshots in the trajectories decreases. Furthermore,analysis of different scenarios illustrates how the deterministicand stochastic forces in the Langevin equation contribute to the variationin dynamics measured by the trajectory entropy. [ABSTRACT FROM AUTHOR]

The dynamics of a protein along awell-defined coordinate can beformally projected onto the form of an overdamped Lagevin equation.Here, we present a comprehensive statistical-learning framework forsimultaneously quantifying the deterministic force (the potentialof mean force, PMF) and the stochastic force (characterized by thediffusion coefficient, D) from single-molecule Förster-typeresonance energy transfer (smFRET) experiments. The likelihood functionalof the Langevin parameters, PMF and D, is expressedby a path integral of the latent smFRET distance that follows Langevindynamics and realized by the donor and the acceptor photon emissions.The solution is made possible by an eigen decomposition of the time-symmetrizedform of the corresponding Fokker–Planck equation coupled withphoton statistics. To extract the Langevin parameters from photonarrival time data, we advance the expectation-maximization algorithmin statistical learning, originally developed for and mostly usedin discrete-state systems, to a general form in the continuous spacethat allows for a variational calculus on the continuous PMF function.We also introduce the regularization of the solution space in thisBayesian inference based on a maximum trajectory-entropy principle.We use a highly nontrivial example with realistically simulated smFRETdata to illustrate the application of this new method. [ABSTRACT FROM AUTHOR]

Abstract: A methodology for assessment of the potential impacts of extraction of energy associated with astronomical tides is described and applied to a site on the Beaufort River in coastal South Carolina, USA. Despite its name, the site features negligible freshwater inputs; like many in the region, it is a tidal estuary that resembles a river. A three-dimensional, numerical, hydrodynamic model was applied for a period exceeding a lunar month, allowing quantification of harmonic constituents of water level and velocity, and comparison to values derived from measurements, recorded at a location within the model domain. The measurement campaign included surveys of bathymetry and velocity fields during ebb and flood portions of a tidal cycle for model validation. Potential far-field impacts of a generic tidal energy conversion device were simulated by introducing an additional drag force in the model to enhance dissipation, resulting in 10–60% dissipation of the pre-existing kinetic power within a flow cross-section. The model reveals effects of the dissipation on water levels and velocities in adjacent areas, which are relatively small even at the 60% dissipation level. A method is presented to estimate the optimal vertical location for the energy conversion device and the potential power sacrificed by moving to a different altitude. [Copyright &y& Elsevier]

Abstract: A geodatabase of tidal constituents is developed to present the regional assessment of tidal stream power resource in the USA. Tidal currents are numerically modeled with the Regional Ocean Modeling System (ROMS) and calibrated with the available measurements of tidal current speeds and water level surfaces. The performance of the numerical model in predicting the tidal currents and water levels is assessed by an independent validation. The geodatabase is published on a public domain via a spatial database engine with interactive tools to select, query and download the data. Regions with the maximum average kinetic power density exceeding 500W/m2 (corresponding to a current speed of ∼1m/s), total surface area larger than 0.5km2 and depth greater than 5m are defined as hotspots and documented. The regional assessment indicates that the state of Alaska (AK) has the largest number of locations with considerably high kinetic power density, followed by, Maine (ME), Washington (WA), Oregon (OR), California (CA), New Hampshire (NH), Massachusetts (MA), New York (NY), New Jersey (NJ), North and South Carolina (NC, SC), Georgia (GA), and Florida (FL). [Copyright &y& Elsevier]

Abstract: The tidal stream power potential along the coast of the state of Georgia is evaluated based on numerical modeling and validated with the available data. The Georgia coast consists of a complex network of tidal rivers and inlets between barrier islands that funnel and locally amplify the strength of the ambient tidal currents in the region. The number of existing tidal current prediction locations is not sufficient to resolve the temporal and spatial changes in the current speeds and patterns. Therefore, the currents are modeled with the Regional Ocean Modeling System (ROMS) to determine the locations with high tidal stream power potential and the results are validated against measurements. The wetlands and the topographical features are integrated in the computational model with wetting and drying of computational cells. The locations with the largest mean tidal stream power density are identified and their characteristics are provided. The effect of power extraction on estuarine hydrodynamics is simulated by implementing an additional retarding force in the governing momentum equations in ROMS. Two different power extraction schemes are simulated at the Canoochee River. The first scheme involves extracting 20% of the original kinetic power across the entire cross-section of the river, and is found to have substantially lower impact on the original flow than the second scheme with 45% extraction. The summation of removed and residual kinetic powers is found to be larger than the original kinetic power in the cross-section, which is attributed to the recovery in the flow momentum through reorganization of stream flow energy. In both of the cases the major impact on the currents is limited to a partial reach of the river. The change in the maximum and minimum water levels is observed to be on the order of centimeters. [Copyright &y& Elsevier]

A process-based numerical model has been used to study nearshore hydrodynamics on barred beaches. A laboratory experiment with an offshore bar migration case followed by an onshore bar migration is simulated. A new mechanism is incorporated in the model accounting for the breaking-wave persistence improving model performance for wave properties, particularly in the bar-trough region. A cross-shore variation of the breaking-wave parameter is introduced to the dissipation model. The effects of the surface shape parameter and a roller lag on radiation stresses and mean water-level predictions are investigated and found to improve the mean water-level predictions. The cross-shore variation of the momentum balance is presented to illustrate the variation of forcing for the undertow current. The persistence length and the roller lag mechanisms are shown to be important for predictions of the undertow currents on barred beaches and the current predictions are improved once both methods are used. [ABSTRACT FROM AUTHOR]

Abstract: A multi-criteria assessment methodology that accounts for the physical, environmental and socioeconomic constraints is proposed to assist in the selection of the most suitable locations for tidal stream power conversion projects. For this purpose, the tidal stream power resource data are incorporated into a Geographical Information System (GIS) database together with datasets that are related to different aspects of the site selection methodology. The proposed method is applied to the Georgia coast to find and rank the best locations for power conversion. The suitable areas are narrowed down to a subset of the high power density areas that satisfy the constraints of a tidal stream power conversion scheme. A demonstrative ranking procedure with equal weighting factors for all criteria shows that the Savannah, Ogeeche, Canoochee and Medway Rivers and the Cumberland Sound have the best locations for tidal power conversion on the coast of Georgia. This methodology is also applicable to other sites where sufficient geospatial data are available. [Copyright &y& Elsevier]

Abstract: The wave power potential along the southeast Atlantic coast of the United States of America bounded by latitudes 27° N and 38° N and longitudes 82° W and 72° W (i.e. North Carolina, South Carolina, Georgia, and northern Florida) is investigated. The available data from National Data Buoy Center wave stations in the given area are examined. Temporal trends of the wave heights, wave periods and the wave power are analyzed for a time scale of weeks. The time series from the wave stations are downsampled with a 15-day moving average filter with near 50% overlapping to study the seasonal trends. Power calculated from hourly significant wave heights and average wave periods is compared to power calculated using spectral wave density. It is found that a factor of 0.61 needs to be applied to the wave power calculated from hourly significant wave heights and average periods in order to get the same results with the power calculated from spectral wave density. The mean power within 50km of the shore is determined to be ∼9kW/m, whereas higher power (∼15kW/m) is available further offshore. [Copyright &y& Elsevier]

Abstract: Predictions of nearshore and surf zone processes are important for determining coastal circulation, impacts of storms, navigation, and recreational safety. Numerical modeling of these systems facilitates advancements in our understanding of coastal changes and can provide predictive capabilities for resource managers. There exists many nearshore coastal circulation models, however they are mostly limited or typically only applied as depth integrated models. SHORECIRC is an established surf zone circulation model that is quasi-3D to allow the effect of the variability in the vertical structure of the currents while maintaining the computational advantage of a 2DH model. Here we compare SHORECIRC to ROMS, a fully 3D ocean circulation model which now includes a three dimensional formulation for the wave-driven flows. We compare the models with three different test applications for: (i) spectral waves approaching a plane beach with an oblique angle of incidence; (ii) monochromatic waves driving longshore currents in a laboratory basin; and (iii) monochromatic waves on a barred beach with rip channels in a laboratory basin. Results identify that the models are very similar for the depth integrated flows and qualitatively consistent for the vertically varying components. The differences are primarily the result of the vertically varying radiation stress utilized by ROMS and the utilization of long wave theory for the radiation stress formulation in vertical varying momentum balance by SHORECIRC. The quasi-3D model is faster, however the applicability of the fully 3D model allows it to extend over a broader range of processes, temporal, and spatial scales. [Copyright &y& Elsevier]

A process-based numerical modeling System is utilized for predicting littoral sand transport. The intent is to examine conditions slightly more complex than linear waves impinging upon a plane beach. Two factors that we examine are wave skewness and longshore varying bathymetry. An empirical model is used for calculating the skewed bottom wave orbital velocity. The advection of sediment due to the skewed wave velocity is larger and in the direction of the waves, opposite to the results with sinusoidal wave velocities, due to the increase in the bottom shear stress under the wave crests. The model system is also applied to bathymetry containing beach cusps. When the wave field has relatively weak longshore wave power, the currents and the littoral transport exhibit significant longshore variability, thereby altering the overall mean littoral transport. [ABSTRACT FROM AUTHOR]

This paper describes nonintrusive optical techniques to measure large-scale O(10 m×10 m) flows in a laboratory wave basin. Numerous drifters with weak positive flotation are tracked discretely and automatically using a video camera mounted near the laboratory ceiling. Processed drifter tracks are used for dense estimates of mean surface currents over the visible area. Examination of the drifter tracks also shows that waves are imaged and therefore basic wave properties may also be estimated, although this requires some further assumptions. These video based flow observations are presumed to have less precision than in situ measurements; however, the density of measurements from the video far exceeds that which can be obtained using fixed instruments, providing the method’s major advantage. [ABSTRACT FROM AUTHOR]

Abstract: The ubiquitin–proteasome system (UPS) actively controls protein dynamics and local abundance via regulated protein degradation. This study investigates UPS'' roles in the regulation of postsynaptic function and molecular composition in the Drosophila neuromuscular junction (NMJ) genetic system. To specifically impair UPS function postsynaptically, the UAS/GAL4 transgenic method was employed to drive postsynaptic expression of proteasome β2 and β6 subunit mutant proteins, which operate through a dominant negative mechanism to block proteasome function. When proteasome mutant subunits were constitutively expressed, excitatory junctional current (EJC) amplitudes were increased, demonstrating that postsynaptic proteasome function limits neurotransmission strength. Interestingly, the alteration in synaptic strength was calcium-dependent and miniature EJCs had significantly smaller mean amplitudes and more rapid mean decay rates. Postsynaptic levels of the Drosophila PSD-95/SAP97 homologue, discs large (DLG), and the GluRIIB-containing glutamate receptor were increased, but GluRIIA-containing receptors were unaltered. With acute postsynaptic proteasome inhibition using an inducible transgenic system, neurotransmission was similarly elevated with the same specific increase in postsynaptic GluRIIB abundance. These findings demonstrate postsynaptic proteasome regulation of glutamatergic synaptic function that is mediated through specific regulation of GluRIIB-containing glutamate receptors. [Copyright &y& Elsevier]

Waves, currents, and longshore sand transport are calculated locally as a function of position in the nearshore region using process based numerical models. The resultant longshore sand transport is then integrated across the nearshore to provide predictions of the total longshore transport of sand due to waves and longshore currents. Model results are in close agreement with the I1-P1 correlation described by Komar and Inman (1970) and the CERC (1984) formula. Model results also indicate that the proportionality constant in the l1-P2 formula depends weakly upon the sediment size, the shape of the beach profile, and the particular local sediment flux formula that is employed. Model results indicate that the various effects and influences of sediment size tend to cancel out, resulting in little overall dependence on sediment size. [ABSTRACT FROM AUTHOR]

Energetic tidal streams are an especially attractive source of clean energy due to the daily occurrence of high tidal flows. However, before any deployment of tidal turbine farms, it is essential to perform a resource assessment depending on the scope and scale of the project. The International Electrotechnical Commission has developed a technical specification for assessing the tidal stream resource "IEC TS 62600-201" to aid in this effort: determine a particular site's feasibility and design the project layout. In this study, we implemented and validated a three-dimensional numerical model and provided results following the specification for a 'Stage 2' project layout design in a highly energetic tidal channel: Tacoma Narrows of Puget Sound, in the State of Washington, USA. Implementation of the numerical model based on the specification has helped estimate the annual energy production with higher model accuracy. We also used the same setup to evaluate the undisturbed theoretical and technical resources, where the latter included energy extraction from the flow field arranging a hypothetical tidal energy converter array. Ultimately, this work has shown the important role of the technical specification in larger project layout design, which can simultaneously act as a benchmark for other 'Stage 2' theoretical and technical resource assessment studies worldwide. • We conducted a 'Stage 2' tidal energy resource assessment following IEC Guidelines. • The Guidelines helped better predict the AEP required for project layout design. • The model validation and result reporting serve as a benchmark for future studies. [ABSTRACT FROM AUTHOR]

Objective Methods Results Significance Epilepsy is a common neurological disorder affecting 1% of the global population. Loss of consciousness in focal impaired awareness seizures (FIASs) and focal‐to‐bilateral tonic–clonic seizures (FBTCSs) can be devastating, but the mechanisms are not well understood. Although ictal activity and interictal connectivity changes have been noted, the network states of focal aware seizures (FASs), FIASs, and FBTCSs have not been thoroughly evaluated with network measures ictally.We obtained electrographic data from 74 patients with stereoelectroencephalography (SEEG). Sliding window band power, functional connectivity, and segregation were computed on preictal, ictal, and postictal data. Five‐minute epochs of wake, rapid eye movement sleep, and deep sleep were also extracted. Connectivity of subcortical arousal structures was analyzed in a cohort of patients with both SEEG and functional magnetic resonance imaging (fMRI). Given that custom neuromodulation of seizures is predicated on detection of seizure type, a convolutional neural network was used to classify seizure types.We found that in the frontoparietal association cortex, an area associated with consciousness, both consciousness‐impairing seizures (FIASs and FBTCSs) and deep sleep had increases in slow wave delta (1–4 Hz) band power. However, when network measures were employed, we found that only FIASs and deep sleep exhibited an increase in delta segregation and a decrease in gamma segregation. Furthermore, we found that only patients with FIASs had reduced subcortical‐to‐neocortical functional connectivity with fMRI versus controls. Finally, our deep learning network demonstrated an area under the curve of .75 for detecting consciousness‐impairing seizures.This study provides novel insights into ictal network measures in FASs, FIASs, and FBTCSs. Importantly, although both FIASs and FBTCSs result in loss of consciousness, our results suggest that ictal network changes in FIASs uniquely resemble those that occur during deep sleep. Our results may inform novel neuromodulation strategies for preservation of consciousness in epilepsy. [ABSTRACT FROM AUTHOR]

The evaluation of the Fisher information matrix for the probability density of trajectories generated by the over-damped Langevin dynamics at equilibrium is presented. The framework we developed is general and applicable to any arbitrary potential of mean force where the parameter set is now the full space dependent function. Leveraging an innovative Hermitian form of the corresponding Fokker-Planck equation allows for an eigenbasis decomposition of the time propagation probability density. This formulation motivates the use of the square root of the equilibrium probability density as the basis for evaluating the Fisher information of trajectories with the essential advantage that the Fisher information matrix in the specified parameter space is constant. This outcome greatly eases the calculation of information content in the parameter space via a line integral. In the continuum limit, a simple analytical form can be derived to explicitly reveal the physical origin of the information content in equilibrium trajectories. This methodology also allows deduction of least informative dynamics models from known or available observables that are either dynamical or static in nature. The minimum information optimization of dynamics is performed for a set of different constraints to illustrate the generality of the proposed methodology. [ABSTRACT FROM AUTHOR]

Opportunities and constraints for wave energy conversion technologies and projects are evaluated by identifying and characterizing the dominant wave energy systems for United States (US) coastal waters using marginal and joint distributions of the wave energy in terms of the peak period, wave direction, and month. These distributions are computed using partitioned wave parameters generated from a 30 year WaveWatch III model hindcast, and regionally averaged to identify the dominant wave systems contributing to the total annual available energy ( A A E ) for eleven distinct US wave energy climate regions. These dominant wave systems are linked to the wind systems driving their generation and propagation. In addition, conditional resource parameters characterizing peak period spread, directional spread, and seasonal variability, which consider dependencies of the peak period, direction, and month, are introduced to augment characterization methods recommended by international standards. These conditional resource parameters reveal information that supports project planning, conceptual design, and operation and maintenance. The present study shows that wave energy resources for the United States are dominated by long-period North Pacific swells (Alaska, West Coast, Hawaii), short-period trade winds and nor'easter swells (East Coast, Puerto Rico), and wind seas (Gulf of Mexico). Seasonality, peak period spread, and directional spread of these dominant wave systems are characterized to assess regional opportunities and constraints for wave energy conversion technologies targeting the dominant wave systems. [ABSTRACT FROM AUTHOR]

• Wave energy for United States coastal waters is assessed using WaveWatchIII hindcast. • New wave energy resource attribute parameters are proposed. • Frequency, directional, and temporal variability of the wave energy are characterized. • The resource attributes corroborate with distinct regional wave climate features. The wave energy resource is characterized and assessed for coastal waters of the United States to evaluate regional opportunities and constraints for wave energy converter (WEC) projects. Partitioned wave parameters generated from a 30-year WaveWatch III model hindcast are used to estimate the total wave energy potential as an annual available energy (AAE), which is a theoretical annual energy production per unit energy capture length without considering energy conversion losses. The distribution of AAE by peak period, wave direction, month, and year is quantified using summary statistics, including peak period spread, AAE -weighted period, AAE -directionality coefficient, and inter-annual and seasonal temporal variability. Geographical distributions of the AAE and these five resource attributes delineate distinct wave energy resource regions within United States coastal waters, where different opportunities and constraints may influence regional energy planning, WEC project development, and WEC conceptual design. [ABSTRACT FROM AUTHOR]

Automatisms are frequently encountered during video-monitoring of patients with focal epilepsy in the EMU and generally thought to have a low lateralizing value in isolation. Rhythmic ictal nonclonic hand (RINCH) motions have been described in small series as a potentially lateralizing semiologic sign. We aimed to expand on prior work and determine the prevalence, characteristics, and lateralizing value of RINCH motions in general epilepsy monitoring unit (EMU) population with focal epilepsy. All patients with recorded seizures in the EMU were included in our database search. Search was performed to identify seizures with reported RINCH motions. Both electroencephalography (EEG) and video of identified seizures were reviewed. We identified RINCH motions in 131 seizures in 71 patients. Overall seizure localization was temporal in 57 patients, frontotemporal in 3 patients, and extratemporal in 7 patients. We estimated RINCH motions to occur in 8.5% of EMU patients with recorded seizures. The most common RINCH motions in descending order were as follows: hand opening and closing, finger rubbing, milking motions, finger flexion/extension, and pill rolling. The mean RINCH motion latency from seizure onset was 34.48 s in temporal lobe epilepsy and 10.31 s in frontal lobe epilepsy. The RINCH motions were contralateral to seizure onset in 61 of 65 (93.8%) with lateralized seizure onset. Dystonic posturing was present in 43% of seizures with RINCH motions. The RINCH motions are a common sign in focal seizures and should be distinguished from other types of manual automatism as they carry a strong lateralizing value. • Rhythmic ictal nonclonic hand (RINCH) motions are a common sign in focal seizures. • RINCH motions are seen with temporal as well as extra temporal epilepsy. • RINCH motions are most often contralateral to the ictal onset zone. [ABSTRACT FROM AUTHOR]

Automatisms are frequently encountered during video-monitoring of patients with focal epilepsy in the EMU and generally thought to have a low lateralizing value in isolation. Rhythmic ictal nonclonic hand (RINCH) motions have been described in small series as a potentially lateralizing semiologic sign. We aimed to expand on prior work and determine the prevalence, characteristics, and lateralizing value of RINCH motions in general epilepsy monitoring unit (EMU) population with focal epilepsy. All patients with recorded seizures in the EMU were included in our database search. Search was performed to identify seizures with reported RINCH motions. Both electroencephalography (EEG) and video of identified seizures were reviewed. We identified RINCH motions in 131 seizures in 71 patients. Overall seizure localization was temporal in 57 patients, frontotemporal in 3 patients, and extratemporal in 7 patients. We estimated RINCH motions to occur in 8.5% of EMU patients with recorded seizures. The most common RINCH motions in descending order were as follows: hand opening and closing, finger rubbing, milking motions, finger flexion/extension, and pill rolling. The mean RINCH motion latency from seizure onset was 34.48 s in temporal lobe epilepsy and 10.31 s in frontal lobe epilepsy. The RINCH motions were contralateral to seizure onset in 61 of 65 (93.8%) with lateralized seizure onset. Dystonic posturing was present in 43% of seizures with RINCH motions. The RINCH motions are a common sign in focal seizures and should be distinguished from other types of manual automatism as they carry a strong lateralizing value. • Rhythmic ictal nonclonic hand (RINCH) motions are a common sign in focal seizures. • RINCH motions are seen with temporal as well as extra temporal epilepsy. • RINCH motions are most often contralateral to the ictal onset zone. [ABSTRACT FROM AUTHOR]

Background: Lung cancer screening can reduce mortality but can be a complex, multi-step process. Poor health literacy is associated with unfavorable outcomes and decreased use of preventative services, so it is important to address barriers to care through efficient and practical education. The readability of lung cancer screening materials for patients is unknown and may not be at the recommended 6th grade reading level set by the American Medical Association. Our goals were to: (1) measure the health literacy of a lung cancer screening population from an urban academic medical center, and (2) examine the readability of online educational materials for lung cancer screening.Methods: We performed a retrospective cross sectional study at a single urban academic center. Health literacy was assessed using three validated screening questions. To assess the readability of educational materials, we performed a Google search using the phrase, "What is lung cancer screening?" and the Flesch-Kincaid Grade Level (FKGL) formula was used to estimate the grade level required to understand the text.Results: There were 404 patients who underwent lung cancer screening during the study period. The prevalence of inadequate/marginal health literacy was 26.7-38.0%. Fifty websites were reviewed and four were excluded from analysis because they were intended for medical providers. The mean FKGL for the 46 websites combined was 10.6 ± 2.2.Conclusions: Low health literacy was common and is likely a barrier to appropriate education for lung cancer screening. The current online educational materials regarding lung cancer screening are written above the recommended reading level set by the American Medical Association. [ABSTRACT FROM AUTHOR]

Background: Lung cancer remains the most common cause of cancer-related deaths in the USA. Successful implementation of lung cancer screening programs has led to increased detection of peripheral pulmonary lesions (PPL). Robotic-assisted bronchoscopy (RB) is a relatively novel tool used to safely diagnose PPN. Additionally, with the developing precision of personalized medicine and targeted therapy, obtaining adequate tissue for next-generation sequencing (NGS) has become critical to optimizing the medical management of lung cancer. Our aim is to assess the diagnostic yield of RB, identify patient and procedure characteristics associated with performing a diagnostic biopsy, and evaluate the adequacy of tumor cellularity for biomarker identification. Results: We performed a retrospective observational study consecutively enrolling 54 adult patients who underwent RB between January 2022 and March 2023. Records were reviewed for medical comorbidities and smoking status. PPL characteristics included size, location, presence of a bronchus sign on mapping computed tomography (CT) scans, distance from airway and pleura on CT, and days between obtaining CT and the bronchoscopy. Procedural factors included the radial endobronchial ultrasound (r-EBUS) view obtained and the sampling method(s) with which a diagnosis was achieved. Records were reviewed for final pathology and the need for further procedures to establish a diagnosis. Samples that yielded non-small cell lung cancer (NSCLC) were sent for an NGS panel if deemed adequate. The panels were reviewed to identify potentially actionable mutations. Multivariable logistic regression was performed to assess patients and lesions characteristics associated with a diagnostic biopsy. We sampled 56 lesions, 45 (80.4%) were from current or former smokers. The overall diagnostic yield was 73.2% and 68.9% for nodules less than 3 cm. Lesions size ranged from 8 mm nodules to 70 mm masses, with an average size 20.3 mm. Mean nodule size from diagnostic procedures was 21.5 mm and 16.9 mm from non-diagnostic ones (p = 0.04). Logistic regression analysis showed that the presence of a bronchus sign was associated with a diagnostic procedure (OR 19.4, p = 0.023), while lack of a r-EBUS view predicted a non-diagnostic bronchoscopy (OR 0.02, p = 0.013). 28 diagnostic biopsies (68.3%) yielded NSCLC and of the 25 cases that we followed, 22 samples (88%) were adequate for NGS. Conclusions: The presence of a bronchus sign on CT and obtaining r-EBUS view during RB were associated with a higher diagnostic yield. RB successfully sampled PPL with adequate tumor cellularity for NGS. [ABSTRACT FROM AUTHOR]

Background: The outcome of indwelling pleural catheter (IPC) use in hepatic hydrothorax (HH) is unclear. This study aimed to review the safety and feasibility of the IPC in patients with refractory HH.Methods: A retrospective multicenter study of patients with HH from January 2010 to December 2016 was performed. Inclusion criteria were refractory HH treated with an IPC and an underlying diagnosis of cirrhosis. Records were reviewed for patient demographics, operative reports, and laboratory values. The Kaplan-Meier method was used to estimate catheter time to removal. The Cox proportional hazard model was used to evaluate for independent predictors of pleurodesis and death.Results: Seventy-nine patients were identified from eight institutions. Indication for IPC placement was palliation in 58 patients (73%) and bridge to transplant in 21 patients (27%). The median in situ dwell time of all catheters was 156 days (range, 16-1,978 days). Eight patients (10%) were found to have pleural space infection, five of whom also had catheter-site cellulitis. Two patients (2.5%) died secondary to catheter-related sepsis. Catheter removal secondary to spontaneous pleurodesis was achieved in 22 patients (28%). Median time from catheter insertion to pleurodesis was 55 days (range, 10-370 days). Older age was an independent predictor of mortality on multivariate analysis (hazard ratio, 1.05; P = .01).Conclusions: We present, to our knowledge, the first multicenter study examining outcomes related to IPC use in HH. Ten percent infection risk and 2.5% mortality were identified. IPC placement may be a reasonable clinical option for patients with refractory HH, but it is associated with significant adverse events in this morbid population. [ABSTRACT FROM AUTHOR]

Modeling studies of estuary circulation show great sensitivity to the water exchange into and out of adjacent marshes, yet there is significant uncertainty in resolving the processes governing marsh surface flow. The objective of this study is to measure the estuary channel-to-saltmarsh pressure gradient and to guide parameterization for how it affects the surface flow in the high marsh. Current meters and high-resolution pressure transducers were deployed along a transect perpendicular to the nearby Little Ogeechee River in a saltmarsh adjacent to Rose Dhu Island near Savannah, Georgia, USA. The vertical elevations of the transducers were surveyed with static GPS to yield high accuracy water surface elevation data. It is found that water level differences between the Little Ogeechee River and neighboring saltmarsh are up to 15 cm and pressure gradients are up to 0.0017 m of water surface elevation change per m of linear distance during rising and falling tides. The resulting Little-Ogeechee-River-to-saltmarsh pressure gradient substantially affects tidal velocities at all current meter locations. At the velocity measurement station located closest to the Little Ogeechee River bank, the tidal velocity is nearly perpendicular to the bank. At this location, surface flow is effectively modeled as a balance between the pressure gradient force and the drag force due to marsh vegetation and bottom stress using the Darcy–Weisbach/Lindner's equations developed for flow-through-vegetation analysis in open channel flow. The study thus provides a direct connection between the pressure gradient and surface flow velocity in the high marsh, thereby overcoming a long-standing barrier in directly relating flow-through-saltmarsh studies to flow-through-vegetation studies in the open channel flow literature. [ABSTRACT FROM AUTHOR]

Efforts to streamline and codify wave energy resource characterization and assessment for regional energy planning and wave energy converter (WEC) project development have motivated the recent development of resource classification systems. Given the unique interplay between WEC absorption and resource attributes, viz, available wave power frequency, directionality, and seasonality, various consensus resource classification metrics have been introduced. However, the main international standards body for the wave energy industry has not reached consensus on a wave energy resource classification system designed with clear goals to facilitate resource assessment, regional energy planning, project site selection, project feasibility studies, and selection of WEC concepts or archetypes that are most suitable for a given wave energy climate. A primary consideration of wave energy generation is the available energy that can be captured by WECs with different resonant frequency and directional bandwidths. Therefore, the proposed classification system considers combinations of three different wave power classifications: the total wave power, the frequency-constrained wave power, and the frequency-directionally constrained wave power. The dominant wave period bands containing the most wave power are sub-classification parameters that provide useful information for designing frequency and directionally constrained WECs. The bulk of the global wave energy resource is divided into just 22 resource classes representing distinct wave energy climates that could serve as a common language and reference framework for wave energy resource assessment if codified within international standards. • Novel Global WERCS is developed considering three levels of physical WEC constraints. • Total, frequency-, and frequency-directionally constrained wave power classifications are developed. • Dominant peak period bands containing the most wave energy content are delineated. • Most global coastal wave sites fall into just 22 resource classes. • KEYWORDS: Wave energy resource classification, Global wave energy resource, Global wave climate. [ABSTRACT FROM AUTHOR]

A 3D numerical model is used to simulate the distortion of tidal hydrodynamics in the Ogeechee Estuary, GA. The Ogeechee, like many estuaries found in the Southeastern US, consists of shallow channel networks and extensive intertidal storage in the form of wetlands. Such features are known to induce non-linear overtide generation and significant tidal distortion, otherwise known as tidal stage asymmetry. Simulations are run with varying parameters to assess their effects on modeling tidal distortion for the Ogeechee Estuary: bottom friction coefficients, enhanced wetland friction coefficients, and tidal flat elevations. To succinctly quantify the degree of distortion across the domain, the statistical parameters of skewness and asymmetry are calculated for time series of water surface heights and channel volume fluxes. The intertidal storage causes the peak flood flux to occur later and the peak ebb flux to occur earlier, thereby resulting in positive asymmetry for the volume flux for the full estuary. However, ebb dominance is a localized feature and varies throughout the estuary. Increasing the intertidal storage by lowering wetland elevation enhances the effects on high tide and volume flux magnitudes, decreasing the ebb-dominance and volume flux asymmetry typically associated with intertidal storage thereby indicating the importance of the wetland elevation over the total storage volume. Increased channel bottom friction reduces ebb-dominance by extending the duration of the falling tide. More interestingly, increased wetland friction reduces the influence of wetland intertidal storage on tidal distortion. The model suggests an increase in wetland friction does little to dampen wave propagation at high tide but rather impedes the lateral flooding of wetlands, reducing ebb dominance. Tidal flat elevation has the largest impact on distortion for the Ogeechee Estuary whereas enhanced wetland and bottom frictional influences on distortion are small, albeit not insignificant. [ABSTRACT FROM AUTHOR]

• Cerebrovascular disease was found to be associated with functional seizures. • Functional stroke is more common in those with functional seizures than epilepsy. • More than one functional neurological disorder may occur in the same patient. To characterize the relationship between functional seizures (FSe), cerebrovascular disease (CVD), and functional stroke. A retrospective case-control study of 189 patients at a single large tertiary medical center. We performed a manual chart review of medical records of patients with FSe or epileptic seizures (ES), who also had ICD code evidence of CVD. The clinical characteristics of FSe, ES, CVD, and functional stroke were recorded. Logistic regression and Welch's t -tests were used to evaluate the differences between the FSe and ES groups. Cerebrovascular disease was confirmed in 58.7% and 87.6% of patients with FSe or ES through manual chart review. Stroke was significantly more common in patients with ES (76.29%) than FSe (43.48%) (p = 4.07 × 10−6). However, compared to nonepileptic controls FSe was associated with both CVD (p < 0.0019) and stroke (p < 6.62 × 10−10). Functional stroke was significantly more common in patients with FSe (39.13%) than patients with ES (4.12%) (p = 4.47 × 10−9). Compared to patients with ES, patients with FSe were younger (p = 0.00022), more likely to be female (p = 0.00040), and more likely to have comorbid mental health needs including anxiety (p = 1.06 × 10−6), PTSD or history of trauma (e.g., sexual abuse) (p = 1.06 × 10−13), and bipolar disorder (p = 0.0011). Our results confirm the initial observation of increased CVD in patients with FSe and further suggest that patients with FSe may be predisposed to developing another functional neurological disorder (FND) (i.e., functional stroke). We speculate that this may be due to shared risk factors and pathophysiological processes that are common to various manifestations of FND. [ABSTRACT FROM AUTHOR]

Abstract: The processes of wetting and drying have many important physical and biological impacts on shallow water systems. Inundation and dewatering effects on coastal mud flats and beaches occur on various time scales ranging from storm surge, periodic rise and fall of the tide, to infragravity wave motions. To correctly simulate these physical processes with a numerical model requires the capability of the computational cells to become inundated and dewatered. In this paper, we describe a method for wetting and drying based on an approach consistent with a cell-face blocking algorithm. The method allows water to always flow into any cell, but prevents outflow from a cell when the total depth in that cell is less than a user defined critical value. We describe the method, the implementation into the three-dimensional Regional Oceanographic Modeling System (ROMS), and exhibit the new capability under three scenarios: an analytical expression for shallow water flows, a dam break test case, and a realistic application to part of a wetland area along the Georgia Coast, USA. [Copyright &y& Elsevier]

A process is described for computation of bathymetry in and near the surf zone, from spatially varying celerity and breakpoint location data. The procedure involves the use of three submodels: (1) a wave shoaling model (outside of the surf zone); (2) a wave breaking model (defining the offshore boundary of the surf zone); and (3) a wave dissipation model (inside the surf zone). Influence of wave amplitude on the wave dispersion relation and celerity is included. Output includes wave height and water depth throughout the domain. In the application described here, oblique digital video served as the initial data source, although the model could be applied to data derived from other sources. Results are compared with data recorded by in situ sensors and beach profile survey data acquired by traditional means. Results suggest that water depths can be computed within 15% normalized error (equally, less than 0.1 m in biased depth error) for in and near the surf zone characterized by high wave nonlinearity. [ABSTRACT FROM AUTHOR]

The behavior of rip currents with changing bar and gap lengths was tested in a series of laboratory experiments using video-tracked floating drifters. Qualitatively, currents showed strong differences in overall character with changing topography. As narrow gaps became wider, the circulation tended to first travel parallel to the shoreline instead of immediately offshore, although strong offshore-directed flows were found for all topographies. Quantitatively, the width of the rip neck was found to increase slowly when compared to the increasing width of the rip channel. Maximum offshore and longshore velocities showed little dependence on bar or gap lengths, and were found to scale well with the predicted rate of generation of circulation. Finally, volumetric offshore flow rates through the rip channel showed no proportionality with the bar length as predicted by the mass transport hypothesis of rip current strength. [ABSTRACT FROM AUTHOR]

The time course of inhibitory postsynaptic currents (IPSCs) reflects GABAA receptor deactivation, the process of current relaxation following transient activation. Fast desensitization has been demonstrated to prolong deactivation, and these processes have been described as being ‘coupled’. However, the relationship between desensitization and deactivation remains poorly understood. We investigated the ‘uncoupling’ of GABAA receptor macroscopic desensitization and deactivation using experimental conditions that affected these two processes differently. Changing agonist affinity preferentially altered deactivation, changing agonist concentration preferentially altered macroscopic desensitization, and a pore domain mutation prolonged deactivation despite blocking fast desensitization. To gain insight into the mechanistic basis for coupling and uncoupling, simulations were used to systematically evaluate the interplay between agonist affinity, gating efficacy, and desensitized state stability in shaping macroscopic desensitization and deactivation. We found that the influence of individual kinetic transitions on macroscopic currents depended not only on model connectivity, but also on the relationship among transitions within a given model. In addition, changing single rate constants differentially affected macroscopic desensitization and deactivation, thus providing parsimonious kinetic explanations for experimentally observed uncoupling. Finally, these findings permitted development of an algorithmic framework for kinetic interpretation of experimental manipulations that alter macroscopic current properties. [ABSTRACT FROM AUTHOR]

Objective: In patients with medically refractory focal epilepsy, stereotactic‐electroencephalography (SEEG) can aid in localizing epileptogenic regions for surgical treatment. SEEG, however, requires long hospitalizations to record seizures, and ictal interpretation can be incomplete or inaccurate. Our recent work showed that non‐directed resting‐state analyses may identify brain regions as epileptogenic or uninvolved. Our present objective is to map epileptogenic networks in greater detail and more accurately identify seizure‐onset regions using directed resting‐state SEEG connectivity. Methods: In 25 patients with focal epilepsy who underwent SEEG, 2 minutes of resting‐state, artifact‐free, SEEG data were selected and functional connectivity was estimated. Using standard clinical interpretation, brain regions were classified into four categories: ictogenic, early propagation, irritative, or uninvolved. Three non‐directed connectivity measures (mutual information [MI] strength, and imaginary coherence between and within regions) and four directed measures (partial directed coherence [PDC] and directed transfer function [DTF], inward and outward strength) were calculated. Logistic regression was used to generate a predictive model of ictogenicity. Results: Ictogenic regions had the highest and uninvolved regions had the lowest MI strength. Although both PDC and DTF inward strengths were highest in ictogenic regions, outward strengths did not differ among categories. A model incorporating directed and nondirected connectivity measures demonstrated an area under the receiver‐operating characteristic (ROC) curve (AUC) of 0.88 in predicting ictogenicity of individual regions. The AUC of this model was 0.93 when restricted to patients with favorable postsurgical seizure outcomes. Significance: Directed connectivity measures may help identify epileptogenic networks without requiring ictal recordings. Greater inward but not outward connectivity in ictogenic regions at rest may represent broad inhibitory input to prevent seizure generation. [ABSTRACT FROM AUTHOR]

• Temporal encephalocele identification permits targeted successful epilepsy surgery. • We clinically compared temporal encephalocele to mesial temporal sclerosis patients. • Later age at onset, female gender, and no febrile seizure history suggested temporal encephalocele. To review clinical and neuropsychological characteristics and natural history of a series of patients with temporal lobe epilepsy (TLE) and anterior temporal encephaloceles (ATE) and compare them to a similar series of TLE patients with mesial temporal sclerosis (MTS) to identify characteristics suggestive of ATE-related epilepsy. Patients with epilepsy and ATE were identified via clinic encounters and consensus epilepsy surgery conference at a Level 4 epilepsy center. The drug-resistant subset of these patients who underwent epilepsy surgery (twenty-two of thirty-five) were compared to age- and laterality-matched patients with MTS. Clinical, neuropsychological, electrophysiologic, and surgical data were abstracted through chart review. In comparison with MTS, ATE patients were more often female, had significantly later onset of epilepsy, and did not have prior febrile seizures. In addition, ATE patients were more likely to have chronic headaches and other historical features consistent with idiopathic intracranial hypertension (IIH). Failure to identify ATE on initial imaging was common. Most patients had limited temporal cortical resections sparing mesial structures. Of the twenty ATE patients who had a long-term postsurgical follow-up, seventeen (85%) had International League Against Epilepsy (ILAE) Class 1 or 2 outcomes. A shorter duration of epilepsy, female gender, and lack of history of febrile seizures may suggest ATE as an etiology of refractory TLE in adults. Targeted encephalocele resections can result in seizure freedom, underscoring the importance of encephalocele identification. [ABSTRACT FROM AUTHOR]

Rationale Epilepsy and psychogenic nonepileptic spells (PNES) can coexist, often posing diagnostic and therapeutic challenges. We sought to identify clinical and historical characteristics of two groups of patients, those with coexisting epilepsy and PNES and those with PNES alone, and determine the prevalence of coexisting epilepsy/PNES with strict diagnostic criteria in a large group of epilepsy monitoring unit (EMU) patients. Methods We reviewed the medical records of all consecutive patients admitted to the Vanderbilt University Medical Center Adult EMU between July 1, 2007 and June 30, 2012. We identified patients with recorded PNES and classified them as having coexisting epilepsy/PNES or PNES alone and then systematically compared the clinical characteristics of these two groups. Results A total of 1567 patient medical records were reviewed. The prevalence rate of coexisting epilepsy/PNES was 5.2% among all EMU admissions (12.3% of all patients with epilepsy and 14.8% of all patients with PNES). These rates were lower when patients with interictal epileptiform activity (IEA) alone and no recorded ictal discharges were not included in the group with epilepsy (2.6%, 6.2%, and 7.4%, respectively). The accuracy of pre-EMU clinical suspicion was significantly higher in the group with PNES-only. Patients with epilepsy/PNES were significantly more likely to require more than one EMU admission for definitive diagnosis. The first PNES event preceded an epileptic seizure (ES) in 94.4% of patients with epilepsy/PNES. The group with PNES-only had significantly higher suggestibility, and the group with epilepsy/PNES had a significantly higher presence of epilepsy risk factors. Abnormal neurological examination and abnormal brain MRI were also significantly more common in the group with epilepsy/PNES. Conclusions Our study defined the prevalence of coexisting epilepsy/PNES in a large cohort with strict diagnostic criteria and outlined specific clinical and historical characteristics differentiating the two groups of patients with coexisting epilepsy/PNES and PNES-only. These findings should help guide clinicians to reach the correct diagnosis faster and provide appropriate treatment earlier. [ABSTRACT FROM AUTHOR]