gebhart/patrepeval huggingface dataset:
Wavelet-based image processing for digital mammography (2000)

This paper is to evaluate the importance of image preprocessing using multiresolution and multiorientation wavelet transforms on the performance of a previously reported computer assisted diagnostic (CAD) method for breast cancer screening, using digital mammography. An analysis of the influence of WTs on image feature extraction for mass detection is achieved by comparing the discriminate ability of features extracted with and without wavelet based image preprocessing using computed ROC. Three indexes are proposed to assess the segmentation of the mass area with comparison to ground truth. Dat was analyzed on region-of- interest database that included mass and normal regions from digitized mammograms with ground truth. The metrics for measurement of segmentation of the mass clearly demonstrates the importance of image preprocessing methods. Similarly, the relative improvement in performance is observed in feature extraction, where the Az values are increased. The improvement depends on the feature characteristics. The use of methodology in this paper result sin a significant improvement in feature extraction for the previously proposed CAD detection method. We are therefore exploring additional improvement in wavelet based image preprocessing methods, including adaptive methods, to achieve a further improvement in performance on larger image databases.
Ultra Fast H.264/AVC to HEVC Transcoder (2013)

The emerging High Efficiency Video Coding (HEVC) standard achieves significant performance improvement over H.264/AVC standard at a cost of much higher complexity. In this paper, we propose a ultra fast H.264/AVC to HEVC transcoder for multi-core processors implementing Wave front Parallel Processing (WPP) and SIMD acceleration, along with expedited motion estimation (ME) and mode decision (MD) by utilizing information extracted from the input H.264/AVC stream. Experiments using standard HEVC test bit streams show that the proposed transcoder achieves 70x speed up over the HEVC HM 8.1 reference software (including H.264 encoding) at very small rate distortion (RD) performance loss.
Broadband tunable quantum cascade laser for external cavity (2013)

Summary form only given. A homogeneous broad gain bandwidth quantum cascade laser for external cavity is demonstrated. Spectrally homogeneous gain of anticrossed dual-upper state (DAU) design provide wide and stable wavelength tunability with external cavity configuration.Quantum cascade (QC) lasers have become the standard laser light sources for sensing applications in midinfrared region. Distributed feedback (DFB) QC-lasers which allow spectral single-mode emission are the most suitable light sources for applications where high-accuracy is requested. However, narrow wavelength tuning range of the DFB-QC-lasers (-5 cm-1) is a limitation of widespread in sensing applications. External cavity configuration is an alternative approach which allows wide wavelength tuning and various types of QC-gain media for the external cavity are proposed and demonstrated. Most of these are heterogeneous structure (severalwavelength-stack gain media) to extend gain bandwidth of the QC-lasers. Spectrally homogeneous broadband quantum cascade laser was developed and broad tuning was realized with external cavity mode. A unique homogeneous broadband design of QC-laser; anticrossed dual-upper state (DAU) design was employed [1-4] and tuning range of 321 cm-1 (from 6.0 gm to 7.42 gm) in pulsed operation was achieved. Even though the DAU structure is designed to be identical wavelength, its gain bandwidth is compatible to several-wavelength stack gain media. The DAU design also has the unique feature of weak dependence on operating voltage and insensitivity to temperature change [5]. The DAU is promising design for gain media for broadly tunable QC-system.
Design and Pharmacology of <i>N</i>-[(3<i>R</i>)-1,2,3,4-Tetrahydroisoquinolinium- 3-ylcarbonyl]-(1<i>R</i>)-1-(4-chlorobenzyl)- 2-[4-cyclohexyl-4-(1<i>H</i>-1,2,4-triazol- 1-ylmethyl)piperidin-1-yl]-2-oxoethylamine (<b>1</b>), a Potent, Selective, Melanocortin Subtype-4 Receptor Agonist (2002)

Synthetic and natural peptides that act as nonselective melanocortin receptor agonists have been found to be anorexigenic and to stimulate erectile activity. We report the design and development of 1, a potent, selective (1184-fold vs MC3R, 350-fold vs MC5R), small-molecule agonist of the MC4 receptor. Pharmacological testing confirms the food intake lowering effects of MC4R agonism and suggests another role for the receptor in the stimulation of erectile activity.
Haloenol Lactone Is a New Isozyme-selective and Active Site-directed Inactivator of Glutathione S-Transferase (1996)

A haloenol lactone derivative has been synthesized and found to be an isozyme-selective and active site-directed inactivator of glutathione S-transferase (GST). Preincubation of the haloenol lactone (100 microM) with murine Alpha, Mu, or Pi GST isozyme (1.0 microM) at pH 6.5, 37 degrees C resulted in time-dependent loss of enzyme activity with highly selective inhibition of the Pi isozyme (t1/2, approximately 2 min). In a separate experiment, a 10-fold excess of the lactone was incubated with GST-Pi isozyme at 37 degrees C for 3 h, followed by dialysis against Nanopure water. GST activity lost upon incubation with the lactone could not be restored by exhaustive dialysis, and only 8% of enzyme activity for the modified GST remained relative to the control that was treated identically except the lactone was omitted from the incubation. Both control and modified GST were characterized using electrospray ionization mass spectrometry. No native GST (23,478 Da) was observed in the spectrum of modified GST. Instead, protein incubated with the lactone exhibited an increase in molecular mass of 230 Da relative to control GST. The lactone (100 microM) was incubated with GST Pi isozyme (1.0 microM) in the presence of the competitive inhibitor S-hexylglutathione (10 microM), which suppressed time-dependent inhibition of GST by the lactone. The results suggest that this haloenol lactone is an irreversible and active site-directed inhibitor of GST that appears to inhibit the enzyme through two consecutive steps of nucleophilic attack.
Making and breaking the exciton in layered halide hybrid perovskites (2018)

Layered halide hybrid organic−inorganic perovskites [1] have been the subject of intense investigation before the rise of three-dimensional (3D) halide perovskites and their impressive performance in solar cells. Recently, layered perovskites have also been proposed as attractive alternatives for photostable solar cells [2] and revisited for light-emitting devices. Interestingly, these performances can be traced back to extremely efficient internal exciton dissociation through edge states identified on thin films and single crystals [3]. Layered perovskites present fascinating features with inherent quantum and dielectric confinements imposed by the organic layers sandwiching the inorganic core, and computational approaches have successfully help rationalized their properties (excitonic, Rashba effects, etc.) [4-6]. Here, we propose a joint spectroscopic and computational investigation to unravel the origin of the recently identified layer-edge states in layered Ruddlesden-Popper phases with inorganic layers containing n = 1 to 4 octahedra. We show that for n > 2, the system presents a localized surface state within the band gap. Based on our conclusion, we propose an elastic model providing design principles for future layered perovskites with optimized properties for photovoltaics or light emission.
Micromachined Piezoelectrically Actuated Flextensional Transducers For High Resolution Printing (2001)

In this paper, we present a technique for the deposition of inks, toners, organic polymers, fuels, small solid particles, biological and chemical fluids, using a fluid ejector. The ejector design is based on a flextensional transducer that excites the axisymmetric resonant modes of a clamped circular plate. It is constructed by depositing a thin piezoelectric annular plate onto a thin, edge clamped, circular plate. Liquids or solid-particles are placed behind one face of the plate which has a small orifice at its center. By applying an ac signal across the piezoelectric element, continuous or drop-on-demand ejection of fluids has been achieved. The ejected drop size ranges in diameter from 4 μm at 3.5 MHz to 150 μm at 7 kHz, the corresponding ejected drop volume ranges from 34 fl to 1.5 nl, and the corresponding flow rate ranges from 117 nl/s to 10 μl/s. The unique features of the device are that the fluid is not pressurized, the fluid container is chemically or biologically compatible with most fluids, and the vibrating plate contains the orifice as the ejection source. The device is manufactured by silicon surface micromachining and implemented in the form of two-dimensional arrays. Individual elements are made of thin silicon nitride membranes covered by a coating of piezoelectric zinc oxide. Classical thin plate theory and Mindlin plate theory are applied to derive two-dimensional plate equations for the transducer, and to calculate the coupled electromechanical field variables such as mechanical displacement and electrical input impedance. In these methods, the variations across the thickness direction vanish by using the bending moments per unit length or stress resultants. Thus, two-dimensional plate equations for a step-wise laminated circular plate are obtained as well as two different solutions to the corresponding systems. An equivalent circuit of the transducer is also obtained from these solutions.
Plasma-Assisted Reaction Chemical Ionization for Elemental Mass Spectrometry of Organohalogens (2014)

We present plasma-assisted reaction chemical ionization (PARCI) for elemental analysis of halogens in organic compounds. Organohalogens are broken down to simple halogen-containing molecules (e.g., HBr) in a helium microwave-induced plasma followed by negative mode chemical ionization (CI) in the afterglow region. The reagent ions for CI originate from penning ionization of gases (e.g., N2) introduced into the afterglow region. The performance of PARCI-mass spectrometry (MS) is evaluated using flow injection analyses of organobromines, demonstrating 5-8 times better sensitivities compared with inductively coupled plasma MS. We show that compound-dependent sensitivities in PARCI-MS mainly arise from sample introduction biases.
A novel tunable active duplexer MMIC (2012)

In this paper, an electronically tunable active duplexer suitable for reconfigurable wireless transceiver application is presented. For the first time, the design has been realized as a MMIC. A novel capacitance tuning circuit has been implemented in the active duplexer. The design and, simulation and measured results of the tunable active duplexer are presented. The active duplexer MMIC provides an electronically tunable isolation of 20 to 45 dB between isolated ports and a gain of 14.5 to 16.5 dB between coupled ports in the tunable range from 2.32 to 2.48 GHz in both transmit and receive modes. This chip is suitable for 2.3GHz WiMAX and WiBro applications.
Fingerprint Liveness Detection Using Local Ridge Frequencies and Multiresolution Texture Analysis Techniques (2006)

It has been demonstrated that simple and inexpensive techniques are sufficient to spoof fingerprint scanners. Previously, effective use of physiological phenomenon of perspiration is shown as a counter-measure against such attacks. These techniques require more than one image for performing the liveness check and hence may not be suited for on-line processing. In this work, a liveness measure based on single image is developed. The inherent texture and density differences between `live' and `not live' fingerprint images are exploited. Multiresolution texture analysis techniques are used to minimize the energy associated with phase and orientation maps. Cross ridge frequency analysis of fingerprint images is performed by means of statistical measures and weighted mean phase is calculated. These different features along with ridge reliability or ridge center frequency are given as inputs to a fuzzy c-means classifier. The proposed algorithm was applied to a dataset of approximately 58 live, 50 spoof and 28 cadaver fingerprint images, from three different types of scanners. An error rate of 1.4% is achieved. The algorithm provides a faster technique for doing a liveness test which relies on only one fingerprint image.
Synthesis of 1,2,3,4‐tetrahydro‐5<i>H</i>‐[1]benzopyrano[3,4‐<i>c</i>]pyridin‐5‐ones. I. 3‐unsubstituted compounds (1984)

Abstract Synthesis of 1,2,3,4‐tetrahydro‐5 H ‐[1]benzopyrano[3,4‐ c ]pyridin‐5‐ones via a Pechmann condensation of 3‐carbethoxy‐1‐methyl‐4‐piperidone with various phenols is described. The limitations of this method are discussed. Synthesis of the parent ring system 3a via reduction of 1,2,3,4‐tetrahydro‐3‐(phenylmethyl)‐8‐[(1‐phenyl‐1 H ‐tetrazol‐5‐yl)oxy]‐5 H ‐[1]benzopyrano[3,4‐ c ]pyridin‐5‐one ( 5 ) is also described.
High‐Throughput Approaches for the Discovery and Optimization of New Olefin Polymerization Catalysts (2002)

The discovery of new olefin polymerization catalysts is currently a time-intensive trial-and-error process with no guarantee of success. A fully integrated high-throughput screening workflow for the discovery of new catalysts for polyolefin production has been implemented at Symyx Technologies. The workflow includes the design of the metal-ligand libraries using custom-made computer software, automated delivery of metal precursors and ligands into the reactors using a liquid-handling robot, and a rapid primary screen that serves to assess the potential of each metalligand-activator combination as an olefin polymerization catalyst. "Hits" from the primary screen are subjected to secondary screens using a 48-cell parallel polymerization reactor. Individual polymerization reactions are monitored in real time under conditions that provide meaningful information about the performance capabilities of each catalyst. Rapid polymer characterization techniques support the primary and secondary screens. We have discovered many new and interesting catalyst classes using this technology.
Near-field scanning microwave microscope with 100 μm resolution (1996)

We describe the operation of a simple near-field scanning microwave microscope with a spatial resolution of about 100 μm. The probe is constructed from an open-ended resonant coaxial line which is excited by an applied microwave voltage in the frequency range of 7.5–12.4 GHz. We present images of conducting structures with the system configured in either receiving or reflection mode. The images demonstrate that the smallest resolvable feature is determined by the diameter of the inner wire of the coaxial line and the separation between the sample and probe.
Exploiting the Human–Machine Gap in Image Recognition for Designing CAPTCHAs (2009)

Security researchers have, for a long time, devised mechanisms to prevent adversaries from conducting automated network attacks, such as denial-of-service, which lead to significant wastage of resources. On the other hand, several attempts have been made to automatically recognize generic images, make them semantically searchable by content, annotate them, and associate them with linguistic indexes. In the course of these attempts, the limitations of state-of-the-art algorithms in mimicking human vision have become exposed. In this paper, we explore the exploitation of this limitation for potentially preventing automated network attacks. While undistorted natural images have been shown to be algorithmically recognizable and searchable by content to moderate levels, controlled distortions of specific types and strengths can potentially make machine recognition harder without affecting human recognition. This difference in recognizability makes it a promising candidate for automated Turing tests [completely automated public Turing test to tell computers and humans apart (CAPTCHAs)] which can differentiate humans from machines. We empirically study the application of controlled distortions of varying nature and strength, and their effect on human and machine recognizability. While human recognizability is measured on the basis of an extensive user study, machine recognizability is based on memory-based content-based image retrieval (CBIR) and matching algorithms. We give a detailed description of our experimental image CAPTCHA system, IMAGINATION, that uses systematic distortions at its core. A significant research topic within signal analysis, CBIR is actually conceived here as a tool for an adversary, so as to help us design more foolproof image CAPTCHAs.
Using Whispering-Gallery-Mode Resonators for Refractometry (2010)

A method of determining the refractive and absorptive properties of optically transparent materials involves a combination of theoretical and experimental analysis of electromagnetic responses of whispering-gallery-mode (WGM) resonator disks made of those materials. The method was conceived especially for use in studying transparent photorefractive materials, for which purpose this method affords unprecedented levels of sensitivity and accuracy. The method is expected to be particularly useful for measuring temporally varying refractive and absorptive properties of photorefractive materials at infrared wavelengths. Still more particularly, the method is expected to be useful for measuring drifts in these properties that are so slow that, heretofore, the properties were assumed to be constant. The basic idea of the method is to attempt to infer values of the photorefractive properties of a material by seeking to match (1) theoretical predictions of the spectral responses (or selected features thereof) of a WGM of known dimensions made of the material with (2) the actual spectral responses (or selected features thereof). Spectral features that are useful for this purpose include resonance frequencies, free spectral ranges (differences between resonance frequencies of adjacently numbered modes), and resonance quality factors (Q values). The method has been demonstrated in several experiments, one of which was performed on a WGM resonator made from a disk of LiNbO3 doped with 5 percent of MgO. The free spectral range of the resonator was approximately equal to 3.42 GHz at wavelengths in the vicinity of 780 nm, the smallest full width at half maximum of a mode was approximately equal to 50 MHz, and the thickness of the resonator in the area of mode localization was 30 microns. In the experiment, laser power of 9 mW was coupled into the resonator with an efficiency of 75 percent, and the laser was scanned over a frequency band 9 GHz wide at a nominal wavelength of approximately equal to 780 nm. Resonance frequencies were measured as functions of time during several hours of exposure to the laser light. The results of these measurements, plotted in the figure, show a pronounced collective frequency drift of the resonator modes. The size of the drift has been estimated to correspond to a change of 8.5 x 10(exp -5) in the effective ordinary index of refraction of the resonator material.
Lignin peroxidase-catalyzed depolymerization of water soluble polymer derived from subbituminous coal and lignite (1988)

In view of reports that enzymes can depolymerize or otherwise alter lignin, it is to be anticipated that enzymes will also attack some of the linkages in coal. However, the solid and vitreous nature of coal precludes a direct test of this possibility. For this reason, it has been necessary to prepare a coal substrate with minimal chemical alteration which is water soluble in the pH range where enzymes are active. This report describes the preparation and characterization of a coal liquid substrate suitable for enzymes and the ability of lignin peroxidase to alter this material.
An Electrokinetic Separation Route to Source Dialysate from Excess Fluid in Blood (2018)

To improve the health of patients with end-stage renal disease, there is a clear need for slow, continuous hemodialysis, and the primary barrier to a wearable device is the requirement of a large reservoir of dialysate. We describe an electrokinetic means of producing dialysate from the excess fluid extant in the peripheral blood of patients undergoing therapy. A critical feature of this process is the retention of essential components of blood, especially serum albumin. In progress toward this goal, we demonstrate the separation of charged from neutral species in blood plasma at a branched microchannel junction by ion concentration polarization (ICP). Further, we introduce a method that reduces the opportunity for damage to proteins and prevents electrode biofouling. The present approach results in as high as 99.7% retention of albumin and successful separation of neutral metabolites and excess fluid to be utilized as a precursor to dialysate.
Recovery of Cesium from High Level Liquid Nuclear Waste by an Advanced Polymer Composite (2012)

Recovery of 137 Cs is one of the important steps in safe and effective management of High Level Liquid Waste (HLLW). Precipitation, solvent extraction and ion exchange are the prominent processes used for 137 Cs separation. Ion exchange processes, based on inorganic ion-exchangers, have several advantages like high radiation stability of material, high selectivity of Cs over other constituent present in the waste, lower volume of secondary waste generation, simple operational procedure etc. Ammonium molybdophosphate (AMP) is a well established inorganic exchanger for selective separation of Cs from HLLW. However, it cannot be used as such for column operations because of its microcrystalline nature. Use of other polymer based systems have known technical operational problems. ALIX (Advanced Lyophilic Ion-exchanger), recently developed at BARC, is an engineered form of composite ion-exchanger, observed to be useful in separation of Cs+ from highly acidic nuclear waste at demonstrable scale.