gebhart/patrepeval huggingface dataset:
Abstract 15840: Electrogram Morphology Recurrence Analysis Identifies Areas of Consistent Activation Directions and Rotor Activity in a Rapid Atrial Pacing Model of Atrial Fibrillation (2014)

Introduction: Electrogram morphology recurrence (EMR) analysis is a novel mapping technique which characterizes morphology patterns during atrial fibrillation (AF). Using high resolution electrical mapping, we tested the hypothesis that EMR analysis could identify areas of consistent activation directions and rotor activity in a canine rapid atrial pacing model of AF. Methods: Three weeks of rapid right atrial pacing (600 bpm) was performed in six dogs. A triangular plaque was used to obtain 117 simultaneous bipolar AF electrograms from two right and three left atrial locations. EMR plots for each electrogram recording were created by cross-correlation of each activation waveform with each other. The percentage of the most common morphology (REC%) and the mean cycle length (CL) of activations with the most common morphology (CLR) were computed. Activation pattern for each site was classified as either having stable rotors, passive activity, or chaotic activity. Activation vectors were computed and a vector index (VI) was used to measure vector consistency. Results: Figure A shows an example of an EMR plot map from recordings in the left atrium with red indicating areas of high EMR. The sites with the shortest CL had an average CL of 81±13 ms. The sites with the highest REC% had an average value of 99±2%. The sites with the shortest CLR had an average value of 91±17 ms. REC% was highly correlated with VI (Figure B). Minimum CL was only moderately shorter in rotor sites compared to chaotic and passive sites (Figure C). Maximum REC% was significantly higher in rotors sites than in chaotic sites, but not different from passive sites (Figure D). Minimum CLR in the rotor sites were significantly less than both the chaotic and passive sites (Figure E). Conclusions: EMR analysis is a new mapping technique that correlates well with activation vector consistency and can identify rotor activity. This is a promising method for mapping AF that may identify sources that can be targeted for ablation.
Synthesis and Complete Stereochemical Assignment of Psymberin/Irciniastatin A. (2005)

Abstract For Abstract see ChemInform Abstract in Full Text.
Results of a laboratory experiment that tests rotating unbalanced-mass devices for scanning gimbaled payloads and free-flying spacecraft (1994)

Rotating unbalanced-mass (RUM) devices are a new way to scan space-based, balloon-borne, and ground-based gimbaled payloads, like x-ray and gamma-ray telescopes. They can also be used to scan free-flying spacecraft. Circular scans, linear scans, and raster scans can be generated. A pair of RUM devices generates the basic scan motion and an auxiliary control system using torque motors, control moment gyros, or reaction wheels keeps the scan centered on the target and produces some complementary motion for raster scanning. Previous analyses and simulation results show that this approach offers significant power savings compared to scanning only with the auxiliary control system, especially with large payloads and high scan frequencies. However, these claims have never been proven until now. This paper describes a laboratory experiment which tests the concept of scanning a gimbaled payload with RUM devices. A description of the experiment is given and test results that prove the concept are presented. The test results are compared with those from a computer simulation model of the experiment and the differences are discussed.
Multiplicative mismatched filter for optimum sidelobe suppression in Barker codes (2006)

Barker codes are the only known bi-phase codes with the smallest achievable sidelobes. However, the longest Barker code of odd length is proven to be that of length 13. There is also a strong conjecture that the Barker codes of length 2 and 4 are the only ones there are of even length. The code of length 13 achieves a mainlobe to peak sidelobe ratio of only 22.28 dB which is less than the practical requirement of at least 30 dB. Mismatched filters have been proposed in the literature to improve this ratio. This is achieved at the cost of some deterioration in the signal to noise ratio at the filter output. In this paper, very efficient sidelobe suppression of Barker codes of length 13 is achieved through the use of a novel mismatched filter. This mismatched filter is comprised of a conventional matched filter cascaded with a computationally efficient filter based on multiplicative expansion. Several parameters are introduced in the terms of the expansion and are optimized to improve the performance of the filter. A version of this filter with three stages is shown to achieve a mainlobe to peak sidelobe ratio of almost 61.9 dB. This is achieved at the cost of some deterioration in the signal to noise ratio at the filter output. The loss in signal to noise ratio (SNR) is shown to be only 0.2 dB. It is suggested that by applying the proposed technique to compound Barker codes, the mainlobe to peak sidelobe ratio could be maintained while improving the signal to noise ratio performance.
THE WHISKER WEAVING ALGORITHM: A CONNECTIVITY‐BASED METHOD FOR CONSTRUCTING ALL‐HEXAHEDRAL FINITE ELEMENT MESHES (1996)

This paper introduces a new algorithm called whisker weaving for constructing unstructured, all-hexahedral finite element meshes. Whisker weaving is based on the Spatial Twist Continuum (STC), a global interpretation of the geometric dual of an all-hexahedral mesh. Whisker weaving begins with a closed, all-quadrilateral surface mesh bounding a solid geometry, then constructs hexahedral element connectivity advancing into the solid. The result of the whisker weaving algorithm is a complete representation of hex mesh connectivity only: Actual mesh node locations are determined afterwards. The basic step of whisker weaving is to form a hexahedral element by crossing or intersecting dual entities. This operation, combined with seaming or joining operations in dual space, is sufficient to mesh simple block problems. When meshing more complex geometries, certain other dual entities appear such as blind chords, merged sheets, and self-intersecting chords. Occasionally specific types of invalid connectivity arise. These are detected by a general method based on repeated STC edges. This leads into a strategy for resolving some cases of invalidities immediately. The whisker weaving implementation has so far been successful at generating meshes for simple block-type geometries and for some non-block geometries. Mesh sizes are currently limited to a few hundred elements. While the size and complexity of meshes generated by whisker weaving are currently limited, the algorithm shows promise for extension to much more general problems.
Demonstration of a quantum key distribution network in urban fibre-optic communication lines (2017)

We report the results of the implementation of a quantum key distribution (QKD) network using standard fibre communication lines in Moscow. The developed QKD network is based on the paradigm of trusted repeaters and allows a common secret key to be generated between users via an intermediate trusted node. The main feature of the network is the integration of the setups using two types of encoding, i.e. polarisation encoding and phase encoding. One of the possible applications of the developed QKD network is the continuous key renewal in existing symmetric encryption devices with a key refresh time of up to 14 s.
Improved Pressure–Frequency Sensing Subxiphoid Pericardial Access System: Performance Characteristics During In Vivo Testing (2010)

We have designed, synthesized, and tested an improved version of our original subxiphoid access system intended to facilitate epicardial electrophysiology. The new version of the system incorporates a precision fiber-optic pressure sensor and a novel signal analysis algorithm for identifying pressure-frequency signatures which, in the clinical setting, may allow for safer access to the pericardial space. Following in vivo studies on ten adult canine models, we analyzed 215 pressure-frequency measurements made at the distal tip of the access needle, of which 98 were from nonpericardial, 112 were from pericardial, and five were from ventricular locations. The needle locations as identified by the algorithm were significantly different from each other (p < 0.01), and the algorithm had improved performance when compared to a standard fast Fourier transform (FFT) analysis of the same data. Moreover, the structure of the algorithm can potentially overcome the time lags intrinsic to FFT analysis such that the needle's location can be determined in near-real time. Hydrodynamic pressure-frequency measurements made during traversal of the pericardial membrane revealed a distinct change in signal structure between the pericardial and nonpericardial anatomy. We present and discuss the design principles, details of construction, and performance characteristics of this system.
Smart steering with machine learning for wireless mesh networks [Makine öğrenmesi ile kablosuz örgü ağlarda akıllı bağlantı yönlendirme] (2020)

In wireless networks, clients can be steered from one access point (AP) to another for a better internet connection. Although this client steering has large potential to improve overall network service and the user experience, such steering actions may not always yield the desired result and the client may remain persistently connected to its current AP. This issue is referred to as the sticky client problem, which prevents the intended improvement in the network. In this work, in order to address the sticky client problem, Support Vector Machine (SVM) as a batch method and kernel perceptron as an online method are examined based on various network features. Nonlinear classifiers of correct steering actions have been trained to maximize the accuracy of steering actions. In particular, the online kernel perceptron performs sequential learning at APs using the cloud data to decide about steering actions in real time. This algorithm is data-driven, and able to provide optimum steering in realtime. In our experiments, we observed that our batch approach identifies successful steering actions with %95 accuracy. On the other hand, our online algorithm is able to approximate the batch performance by a small margin while allowing real time steering with significantly lower computational complexity.
Carbon-composite filter for radioactive-waste-storage containers (1982)

Rupture and/or bulging of TRU waste containers experiencing pressure buildup due to gas generation can be safely and inexpensively eliminated by fitting each container with a nuclear grade filter vent. The carbon composite filter evaluated in this study meets all material and filtering requirements and is strongly recommended for use as a filter vent in waste containers.
Plasma distribution of cathodic arc deposition systems (1996)

The plasma distribution using a cathodic arc plasma source with and without magnetic macroparticle filter has been determined by depositing on a transparent plastic substrate and measuring the film absorption. It was found that the width of the distribution depends on the arc current, and it also depends on the cathode material which leads to a spatial separation of the elements when an alloy cathode is used. By applying a magnetic multicusp field near the exit of the magnetic filter, it was possible to modify the plasma distribution and obtain a flat plasma profile with a constant and homogeneous elemental distribution which was demonstrated by depositing FeNd thin films.
Electromagnetic Time Reversal Applied to Fault Location: On the Properties of Back-Injected Signals (2018)

By using the electromagnetic time reversal (EMTR) theory, the paper studies its properties in order to derive a new fault location method to be used in power networks. It is shown that, in the reversed-time stage, the current signal observed at the true fault location can be clearly distinguished since it appears as a time-delayed copy of the back-injected fault-originated transient signal. Then, based on this similarity property, a fault location method is derived. Finally, the method is numerically validated with reference to a reproducible simulated power network composed of an inhomogeneous multi-conductor transmission-line system.
In vitro selection of a neutralization-resistant hepatitis C virus escape mutant (2008)

Effective immunization against hepatitis C virus (HCV) infections is likely to require the induction of both robust T and B cell immunity. Although neutralizing antibodies may play an important role in control of infection, there is little understanding of the structure of the HCV envelope glycoproteins and how they interact with such antibodies. An additional challenge for vaccine design is the genetic diversity of HCV and the rapid evolution of viral quasispecies that escape antibody-mediated neutralization. We used a cell culture-infectious, chimeric HCV with the structural proteins of genotype 1a virus to identify envelope residues contributing to the epitope recognized by a broadly neutralizing, murine monoclonal antibody, AP33. By repetitive rounds of neutralization followed by amplification, we selected a population of viral escape mutants that resist stringent neutralization with AP33 and no longer bind the antibody. Two amino acid substitutions, widely separated in the linear sequence of the E2 envelope protein (N415Y and E655G), were identified by sequencing of cloned cDNA and shown by reverse genetics analysis to contribute jointly to the AP33 resistance phenotype. The N415Y mutation substantially lowered virus fitness, most likely because of a defect in viral entry, but did not reduce binding of soluble CD81 to immobilized HCV-pseudotyped retrovirus particles. The in vitro selection of an HCV escape mutant recapitulates the ongoing evolution of antigenic variants that contributes to viral persistence in humans and reveals information concerning the conformational structure of the AP33 epitope, its role in viral replication, and constraints on its molecular evolution.
Injection-locking of diode-laser arrays with a stable single-mode cw dye laser (1985)

The injection of optical radiation from a master oscillator into a diode-laser array provides a means for achieving a single-lobed single-frequency output beam at power levels exceeding 100-mW cw. In our study of injection locking in diode-laser arrays, we used a single-frequency tunable cw dye laser as a master oscillator. This approach provides us with considerable control over the injection wavelength, bandwidth, intensity, and spatial profile. With a commercial ten-element diode-laser array operating at 100-mW output, we observe a single-lobed off-axis far-field beam pattern when a single element at either end of the array is injected at milliwatt power levels. In injection-locking conditions, a diode-laser linewidth of ≤2 MHz and a detuning range of several tens of gigahertz were measured. We also observe an angular scanning (1.2°) of the emission angle of the single-lobed output beam of the diode-laser array as the injection wavelength is varied over 50 GHz. This angular steering capability is of potential importance for the rapid direct pointing and scanning of diode-laser arrays.
Fluorescently Detectable Magnetic Resonance Imaging Agents (1998)

This report describes the synthesis, characterization, and in vivo testing of several bifunctional contrast-enhancing agents for optical and magnetic resonance imaging (MRI) of experimental animals. These new agents integrate the advantages of both techniques since they can be visualized simultaneously by light and MRI microscopy. Employing this strategy allows the same biological structures of a specimen to be studied at dramatically different resolutions and depths. The complexes possess a metal chelator for binding a paramagnetic ion, gadolinium (Gd3+), and a covalently attached fluorescent dye. The first class of complexes are low-molecular weight species that are composed of the macrocyclic tetraamine 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) as the metal-chelating ligand coupled to tetramethylrhodamine. The second class of MRI-enhancing agents are composed of high-molecular weight polymers that are membrane impermeable and once injected into a cell or cells are trapped inside. These complexes possess multiple copies of both the metal-chelator-diethylenetriaminepentaacetic acid (DTPA) and the tetramethylrhodamine attached to a macromolecular framework of either poly(D-lysine) (pdl) or dextran. Images acquired of single cells after injection with these bifunctional agents enabled us to follow the relative motions and reorganizations of different cell layers during amphibian gastrulation and neurulation in Xenopus laevis embryos.
Hemoglobin Correction for Near-Infrared pH Determination in Lysed Blood Solutions (2003)

The near-infrared (NIR) measurement of blood pH relies on the spectral signature of histidine residing on the hemoglobin molecule. If the amount of hemoglobin in solution varies, the size of the histidine signal can vary depending on changes in either the pH or hemoglobin concentration. Multivariate calibration models developed using the NIR spectra collected from blood at a single hemoglobin concentration are shown to predict data from different hemoglobin levels with a bias and slope. A simple, scalar path length correction of the spectral data does not correct this problem. However, global partial least-square (PLS) models built with data encompassing a range of hemoglobin concentration have a cross-validated standard error of prediction (CVSEP) similar to the CVSEP of data obtained from a single hemoglobin level. It will be shown that the prediction of pH of an unknown sample using a global PLS model requires that the unknown have a hemoglobin concentration falling within the range encompassed by the global model. An alternative method for correcting the predicted pH for hemoglobin levels is also presented. The alternative method updates the single-hemoglobin-level models with slope and intercept estimates from the pH predictions of data collected at alternate hemoglobin levels. The slope and intercept correction method gave SEP values averaging to 0.034 pH units. Since both methods require some knowledge of the hemoglobin concentration in order for a pH prediction to be made, a model for hemoglobin concentration is developed using spectral data and is used for pH correction.
Delegation of cryptographic servers for capture-resilient devices (2001)

A device that performs private key operations (signatures or decryptions), and whose private key operations are protected by a password, can be immunized against offline dictionary attacks in case of capture by forcing the device to confirm a password guess with a designated remote server in order to perform a private key operation. Recent proposals for achieving this allow untrusted servers and require no server initialization per device. In this paper we extend these proposals to enable dynamic delegation from one server to another; i.e., the device can subsequently use the second server to secure its private key operations. One application is to allow a user who is traveling to a foreign country to temporarily delegate to a server local to that country the ability to confirm password guesses and aid the user's device in performing private key operations, or in the limit, to temporarily delegate this ability to a token in the user's possession. Another application is proactive security for the device's private key, i.e., proactive updates to the device and servers to eliminate any threat of offline password guessing attacks due to previously compromised servers.
The Discovery of Two Novel Classes of 5,5-Bicyclic Nucleoside-Derived PRMT5 Inhibitors for the Treatment of Cancer (2021)

Protein arginine methyltransferase 5 (PRMT5) is a type II arginine methyltransferase that catalyzes the post-translational symmetric dimethylation of protein substrates. PRMT5 plays a critical role in regulating biological processes including transcription, cell cycle progression, RNA splicing, and DNA repair. As such, dysregulation of PRMT5 activity is implicated in the development and progression of multiple cancers and is a target of growing clinical interest. Described herein are the structure-based drug designs, robust synthetic efforts, and lead optimization strategies toward the identification of two novel 5,5-fused bicyclic nucleoside-derived classes of potent and efficacious PRMT5 inhibitors. Utilization of compound docking and strain energy calculations inspired novel designs, and the development of flexible synthetic approaches enabled access to complex chemotypes with five contiguous stereocenters. Additional efforts in balancing bioavailability, solubility, potency, and CYP3A4 inhibition led to the identification of diverse lead compounds with favorable profiles, promising <i>in vivo</i> activity, and low human dose projections.
A genetic system for targeted mutations to disrupt and restore genes in the obligate bacterium, Ehrlichia chaffeensis (2017)

Obligate intracellular bacteria (obligates) belonging to Rickettsiales and Chlamydiales cause diseases in hundreds of millions of people worldwide and in many animal species. Lack of an efficient system for targeted mutagenesis in obligates remains a major impediment in understanding microbial pathogenesis. Challenges in creating targeted mutations may be attributed to essential nature of majority of the genes and intracellular replication dependence. Despite success in generating random mutations, a method that works well in creating mutations in specific genes of interest followed by complementation remains problematic for obligates and is a highly sought-after goal. We describe protocols to generate stable targeted mutations by allelic exchange in Ehrlichia chaffeensis, an obligate intracellular tick-borne bacterium responsible for human monocytic ehrlichiosis. Targeted mutations in E. chaffeensis were created to disrupt two genes, and also to restore one gene by another allelic exchange mutation leading to the restoration of transcription and protein expression from the inactivated gene and the recovered organisms also express mCherry, which distinguishes from the wild type. We expect that the methods developed are broadly applicable to other obligates, particularly to rickettsial pathogens, to routinely perform targeted mutations to enable studies focused on protein structure-function analyses, host-pathogen interactions and in developing vaccines.