gebhart/patrepeval huggingface dataset:
Sample Efficient Toeplitz Covariance Estimation (2019)

We study the sample complexity of estimating the covariance matrix T of a distribution over d-dimensional vectors, under the assumption that T is Toeplitz. This assumption arises in many signal processing problems, where the covariance between any two measurements only depends on the time or distance between those measurements. We are interested in estimation strategies that may choose to view only a subset of entries in each vector sample x ∼ , which often equates to reducing hardware and communication requirements in applications ranging from wireless signal processing to advanced imaging. Our goal is to minimize both 1) the number of vector samples drawn from and 2) the number of entries accessed in each sample. We provide some of the first non-asymptotic bounds on these sample complexity measures that exploit T's Toeplitz structure, and by doing so, significantly improve on results for generic covariance matrices. These bounds follow from a novel analysis of classical and widely used estimation algorithms (along with new variants), including methods based on selecting entries from each vector sample according to a so-called sparse ruler. In addition to results that hold for any Toeplitz T, we further study the important setting when T is close to low-rank, which is often the case in practice. We show that methods based on sparse rulers perform even better in this setting, with sample complexity scaling sublinearly in d. Motivated by this, we develop a new estimation strategy that further improves on existing methods in the low-rank case: when T is rank-k or nearly rank-k, it achieves sample complexity depending polynomially on k and only logarithmically on d. Our results utilize tools from random matrix sketching, leverage score based sampling techniques for continuous time signals, and sparse Fourier transform methods. In many cases, we pair our upper bounds with matching or nearly matching lower bounds.
A Compiler Analysis to Determine Useful Cache Size for Energy Efficiency (2013)

As processor and memory system speeds have significantly diverged, system designers have introduced ever larger caches in an effort to supply the processor with data at a rate it is capable of processing it. However, application characteristics vary and not all programs can effectively utilize large caches due to their inherent data reuse properties. The inability to use all the available cache capacity leads to wasted cache power dissipation. The rising specter of "dark silicon" makes it critical to avoid wasted power on a chip.In this paper, we develop a compile-time approach to analyze data reuse characteristics of affine computations and deduce the useful cache size(s) for a given system configuration. The non-useful cache can be power-gated to save power. Analysis of benchmarks shows that significant fractions of the last level cache of current processors may be turned off with no performance loss.
The Sensitivity of Dermatophytes to the Antimicrobial Activity of Manuka Honey and Other Honey (1996)

Honey has been reported to have antifungal activity and so was tested against clinical isolates of the common dermatophyte species which cause tineas in man. A honey with an average level of hydrogen peroxide, and a manuka (Leptospermum scoparium J. R. and G. Forst, family Myrtaceae) honey with an average level of non-peroxide antibacterial activity were used. An agar well diffusion assay was used, the contents of the wells being replaced with freshly prepared honey solutions at 24-h intervals over the 3–4 days of incubation.

The lowest concentrations (% v/v, in steps of 5%) of manuka honey with catalase added to remove hydrogen peroxide, and of the other honey (without catalase) showed that inhibition of growth around the wells were, respectively, Epidermophyton floccosum 25%, 10%; Microsporum canis 25%, 15%; Microsporum gypseum 55%, 20%; Trichophyton mentagrophytes var. interdigitale 45%, 15%; Trichophyton mentagrophytes var. mentagrophytes 25%, 15%; Trichophyton rubrum 20%, 5% and Trichophyton tonsurans 25%, 20%. No inhibitory activity was detected with the other honey at 50% (v/v) with catalase added.

The results of this investigation show that the common dermatophytes are sensitive to the antimicrobial activity of honey, indicating that clinical evaluation of honey in the treatment of tineas is warranted. This would determine whether the hydrogen peroxide or the non-peroxide antifungal agent diffuses better into the skin.
γδd T cells promote the maturation of dendritic cells during West Nile virus infection (2010)

gammadelta T cells are important for the early control of West Nile virus (WNV) dissemination. Here, we investigated the role of gammadelta T cells in the regulation of CD4(+) T-cell response following a WNV challenge. Splenic dendritic cells (DCs) of WNV-infected gammadelta T-cell-deficient (TCRdelta(-/-)) mice displayed lower levels of CD40, CD80, CD86 and major histocompatibility complex (MHC) class II expression and interleukin-12 (IL-12) production than those of wild-type mice. Naïve DCs cocultured with WNV-infected gammadelta T cells showed enhanced levels of costimulatory molecules, MHC class II expression and IL-12 production. Further, coculture of CD4(+) T cells from OT II transgenic mice with DCs of WNV-infected TCRdelta(-/-) mice induced less interferon-gamma (IFN-gamma) and IL-2 production than with those of wild-type controls. Viral antigens were detected in WNV-infected gammadelta T cells.WNV infection or toll-like receptor (TLR) agonist treatment of gammadelta T cells induced the production of IFN-gamma, tumor necrosis factor-alpha and IL-6, which are known to promote DC maturation. Nevertheless, the levels of TLRs 2, 3, 4 and 7 expression of WNV-infected gammadelta T cells were not different from those of noninfected cells. Overall, these data suggest that WNV-induced gammadelta T-cell activation promotes DC maturation and initiates CD4(+) T-cell priming.
Association of Left Ventricular Remodeling and Nonuniform Electrical Recovery Expressed by Nondipolar QRST Integral Map Patterns in Survivors of a First Anterior Myocardial Infarction (1995)

Nondipolar map patterns are present in 32% of patients after thrombolysis for a first anterior myocardial infarction and are associated with increased left ventricular dilatation. These data support the hypothesis that left ventricular dilatation after myocardial infarction leads to changes in repolarization characteristics that may facilitate the occurrence of life-threatening ventricular arrhythmias.
Solid‐State Pyrolysis of Polyphenylene–Metal Complexes: A Facile Approach Toward Carbon Nanoparticles (2007)

Abstract Novel polyphenylene–metal complexes with discotic, linear, and dendritic geometries are synthesized by using a facile approach consisting of reactions between Co 2 (CO) 8 and ethynyl functionalities in dichloromethane. Various carbon nanoparticles (CNPs), including graphitic carbon nanotubes (CNTs), graphitic carbon rods, and carbon–metal hybrid particles are obtained from the solid‐state pyrolysis of these complexes. The ultimate structures of the CNPs are found to be dependant on the structure and composition of the starting compounds. Precursors containing graphenes always result in graphitic CNTs in high yield, whereas dendritic precursors give rodlike carbon materials. Alternatively, linear oligo(arylethylene) precursors afford mostly carbon–metal hybrids with large amounts of amorphous carbon. Furthermore, the CNP structures could be controlled by adjusting the carbon/metal ratio, the type and position of the metal incorporated into the precursor, and the mode of pyrolysis. These results provide further chances toward understanding the mechanism of CNP formation.
Task Group D - HPFRCC Design Assumptions - Conclusions (2006)

Peer Reviewed
High-Throughput Visual MIMO Systems for Screen-Camera Communications (2020)

Screen-camera communications, using a liquid crystal display (LCD) screen and camera image sensors, have been attractive variants of visible light communications (VLC) since any external light-emitting modules and photo detectors are required for recent mobile devices, which are usually equipped with display and camera. A major issue in screen-camera communications is a performance loss in transmission rate due to nonlinear channel impairments with ambient noise. To improve transmission rates, we investigate the impact of nonlinear channel equalization, nonbinary channel coding, probabilistic shaping, and nonlinear precoding for high-order modulation schemes. Experimental evaluations using an LCD screen and camera demonstrate that our proposed scheme achieves 3.8-3.3 times higher transmission rates compared to existing schemes for a communication distance of 60-160 cm.
Impact of printed circuit board technology on thermal performance of high-power LED assembly - experimental results (2010)

In the last half decade LED technology has undoubtedly made its most rapid progresses leading to an enormous growth of illumination applications. Though, this advancement is based on a series of quantum steps in improvement of efficiency, removal of the remaining power loss is a major concern in further developments. In our paper we compare LED demonstrator assemblies with three different types of high-power LEDs mounted on different types of printed circuit boards. The thermal performance of the respective combination is investigated. We found that in a power loss range of a few Watts a satisfying solution can frequently be attained by application of conventional glass fiber epoxy based PCB technology with advanced thermal design (improved heat-spreading capability by thermal pads and thermal vias). For dissipating higher power loss, however, the insulated metal substrates turned out to be superior with respect to their polymer-based counterparts, particularly if the PCB itself has to fulfil cooler or heat spreader function. Moreover, some aspects of the dynamic thermal behavior of different demonstrator boards assembled with the same LED type were studied by recording temperature changes on the LED surface during the heating-up phase.
Hidden Gratings in Holographic Liquid Crystal Polymer-Dispersed Liquid Crystal Films (2018)

Dynamic diffraction gratings that are hidden in the field-off state are fabricated utilizing a room-temperature photocurable liquid crystal (LC) monomer and nematic LC (NLC) using holographic photopolymerization techniques. These holographic LC polymer-dispersed LCs (HLCPDLCs) are hidden because of the refractive index matching between the LC polymer and the NLC regions in the as-formed state (no E-field applied). Application of a moderate E-field (5 V/μm) generates a refractive index mismatch because of the NLC reorientation (along the E-field) generating high-diffraction efficiency transmission gratings. These dynamic gratings are characterized by morphological, optical, and electrooptical techniques. They exhibit a morphology made of oriented LC polymer regions (containing residual NLC) alternating with a two-phase region of an NLC and LC polymer. Unlike classic holographic polymer-dispersed LC gratings formed with a nonmesogenic monomer, there is index matching between the as-formed alternating regions of the grating. These HLCPDLCs exhibit broad band and high diffraction efficiency (≈90%) at the Bragg angle, are transparent to white light across the visible range because of the refractive index matching, and exhibit fast response times (1 ms). The ability of HLCPDLCs not to consume electrical power in the off state opens new possibilities for the realization of energy-efficient switchable photonic devices.
Elastic properties of human posterior eye (2013)

This study examines the elastic properties of the human posterior retina, choroid, and sclera. Twenty-four human eyes from 30- to 74-year-old donors were obtained from an eye bank. Vertically and horizontally oriented tissue strips of the retina, choroid, and sclera (ideally n = 12 in each group) were harvested from the posterior eyes. Their thicknesses were estimated optically. The samples were stretched at 1 mm/s in 37°C saline. Stress and strain were obtained from the mechanical tests, and then the transition stress, transition strain, toe modulus, and heel modulus were calculated. Statistical analysis was performed for comparison between groups. Linear regression analyses were used to explore the relationship between the mechanical parameters and age. We found that the stress-strain relationship of the retina, choroid, and sclera were nonlinear. Except for the retinal transition strain (p = 0.0124), no statistical difference was found between the vertical and horizontal meridian in the mechanical parameters (p > 0.05). Furthermore, weak relationship was observed between some of the mechanical parameters and the donors' age. Our results suggest that there is significant anisotropy in the retina, and mechanical properties of each layer may change with age.
Sequential Knoevenagel [4+1] Cycloaddition–Condensation–Aza-Friedel–Crafts Intramolecular Cyclization: A 4-Center-3-Component Reaction Toward Tunable Fluorescent Indolizine Tetracycles (2021)

A two-step multicomponent reaction oxidation protocol is reported herein, which affords novel tunable fluorescent tetracyclic indolizines. The procedure involves a novel 4-center-3-component reaction, which proceeds via a sequential Knoevenagel condensation, [4+1] cycloaddition, and imine condensation to afford imino-indolizines. Products then undergo cyclization and are oxidized <i>in situ</i> to afford fluorescent tetracycles, which are readily tunable through modification of diversity elements.
Embeddings of curves in the plane (1998)

In this paper, we contribute toward a classification of two-variable polynomials by classifying (up to an automorphism of $C^2$) polynomials whose Newton polygon is either a triangle or a line segment. Our classification has several applications to the study of embeddings of algebraic curves in the plane. In particular, we show that for any $k \ge 2$, there is an irreducible curve with one place at infinity, which has at least $k$ inequivalent embeddings in $C^2$. Also, upon combining our method with a well-known theorem of Zaidenberg and Lin, we show that one can decide "almost" just by inspection whether or not a polynomial fiber is an irreducible simply connected curve.
Direct Tendon Attachment and Healing to Porous Tantalum (2007)

Background: The ability to directly attach soft-tissue to metal would have broad clinical application. Previous attempts to obtain normal tendon-to-bone attachment strength have been unsuccessful. In the present study, we hypothesized that when the initial interface mechanical environment is carefully controlled, a highly porous form of tantalum metal would allow the ingrowth of tendon tissue with clinically relevant tendon-to-implant fixation strength approaching that of an intact tendon-to-bone insertion. Methods: Supraspinatus tendons from forty skeletally mature dogs were reattached to the greater tuberosity between two custom-designed porous tantalum washers. Clinical function as judged on the basis of gait analysis, reattachment fixation strength and stiffness, and tendon function as seen through muscle volume were evaluated preoperatively, immediately postoperatively, and at three, six, and twelve weeks after surgery. Qualitative and quantitative histomorphologic evaluation was performed at three, six, and twelve weeks after surgery. Results: Gait analysis with use of force-plate measurements demonstrated return to a normal gait pattern by three weeks after surgery. Tendon-implant strength as a percentage of normal, contralateral controls increased significantly, from 39% at the time of surgery to 67% at three weeks, 99% at six weeks, and 140% at twelve weeks (p < 0.0014). The stiffness of the construct also increased and approached that of normal tendon, measuring 47% at the time of surgery, 62% at three weeks, 94% at six weeks, and 130% at twelve weeks (p < 0.0299). Supraspinatus muscle volume initially decreased by 33% but recovered to 92% of normal by twelve weeks (p < 0.01). Histomorphologic evaluation showed Sharpey-like fibers inserting onto the surface of the porous tantalum. Quantitative histomorphometric analysis revealed a time-dependent increase in the density of the collagen tissue filling the metal voids below the implant surface of first the bottom washer and then the top washer. Conclusions: Robust biologic ingrowth of tendon into a porous tantalum implant surface can be achieved under conditions of secure initial mechanical fixation. The strength and stiffness of the tendon-implant construct reached normal levels by six to twelve weeks in this animal model. Clinical Relevance: Our results demonstrate the potential utility of highly porous metals in general and this specific form of porous tantalum in particular as a biomaterial for soft-tissue reconstruction. The ability to achieve healing of tendon and possibly other soft tissues directly to metallic devices should offer opportunities for the development of novel and potentially more physiologic orthopaedic implants.
Tracking the interplay between circulating and tumor-infiltrating T cells using AmpliSeq-based Ion Torrent TCRβ immune repertoire sequencing. (2017)

e14518 Background: TCRβ immune repertoire analysis by next-generation sequencing is emerging as a valuable tool for research studies of the tumor microenvironment and potential immune responses to future cancer immunotherapy. Here we describe a multiplex PCR-based TCRβ sequencing assay that takes advantage of the exceptionally low base-call error rate and long read capability of the Ion S5 530 chip. The S530 chip provides &gt; 15M reads, allowing for sample sequencing in multiplex. The research assay utilizes AmpliSeq technology and Framework 1 and Constant gene targeting primers to provide comprehensive coverage of TCRβ CDR 1, 2 and 3 from RNA input with a hands-on time of less than 30 minutes. CDR region sequences reveal the antigen specificity of the receptor and may be genetically modified to increase TCR affinity for tumor antigen. Methods: We evaluated assay performance by sequencing TCRβ rearrangements from normal donor peripheral blood leukocyte (PBL) cDNA that had been spiked with 30 reference rearrangements taken from the literature. We then used our assay to evaluate the extent of clonal overlap between matched tumor infiltrating lymphocyte (TIL) and peripheral blood leukocyte repertoires in an individual with squamous cell carcinoma of lung. Results: Results from sequencing of spike-in reference rearrangements indicate that the assay is accurate and sensitive over 5 logs of input template amount while showing minimal amplification bias. Sequencing of matched PBL and TIL repertoires revealed that a subset of the PBL repertoire (8%) consisted of clones also found in TIL. Technical replicates showed high concordance (r &gt; .96) in the frequency of detected clones, indicating that the results were reproducible and samples were sequenced to an appropriate depth. Conclusions: In summary, these data suggest that AmpliSeq-based multiplex PCR and Ion Torrent sequencing provide unbiased, reproducible, scalable, complete, and accurate information for immune repertoire research sequencing applications.
Flutter Testing Methodology for Swirl Distortion Generators (2023)

View Video Presentation: https://doi.org/10.2514/6.2023-2573.vid StreamVane devices are swirl distortion generators consisting of complex vane packs used to recreate secondary flow distortions. To ensure the structural integrity of these complex vane packs, further research was needed to study flutter of these devices and complex vane packs in general. The objective of this research was to develop a methodology for studying flutter in these devices and take an initial look at possible mechanisms that could cause it. High speed cameras were used to observe the onset of flutter and record the trailing edge motion. A method was then developed using this calibrated high speed video to obtain accurate displacements along the trailing edge of the vanes. For this investigation, two StreamVanes were designed outside of standard design guidelines to increase the likelihood they would flutter. These StreamVanes consisted of a larger, complex vane pack and a more simple vane pack taken from one section of that larger one. These devices were found to flutter in a similar Mach number range indicating flutter more localized geometric features could be an issue and not just the entire complex structure. Steady CFD was then performed to examine the flow structure and local Mach numbers through the passages. This identified some possible aerodynamic issues such as separation and transonic flow that could lead to unsteadiness and other potential problems. These results provide some insight into the flutter behavior of these complex vane packs and will serve as a baseline for future research into the structural integrity of these devices.
Amorphous BiTe plasmonics dataset (2018)

Dataset for "Compositionally tunable plasmonics in amorphous semiconductor metasurfaces"
Frame Rate Up-Conversion Using Key Point Agnostic Frequency-Selective Mesh-to-Grid Resampling (2021)

High frame rates are desired in many fields of application. As in many cases the frame repetition rate of an already captured video has to be increased, frame rate up-conversion (FRUC) is of high interest. We conduct a motion compensated approach. From two neighboring frames, the motion is estimated and the neighboring pixels are shifted along the motion vector into the frame to be reconstructed. For displaying, these irregularly distributed mesh pixels have to be resampled onto regularly spaced grid positions. We use the model-based key point agnostic frequency-selective mesh-to-grid resampling (AFSMR) for this task and show that AFSMR works best for applications that contain irregular meshes with varying densities. AFSMR gains up to 3.2 dB in contrast to the already high performing frequency-selective mesh-to-grid resampling (FSMR). Additionally, AFSMR increases the run time by a factor of 11 relative to FSMR.
Hybrid Composites for LH2 Fuel Tank Structure (2001)

The application of lightweight carbon fiber reinforced plastics (CFRP) as structure for cryogenic fuel tanks is critical to the success of the next generation of Reusable Launch Vehicles (RLV). The recent failure of the X-33 composite fuel tank occurred in part due to microcracking of the polymer matrix, which allowed cryogen to permeate through the inner skin to the honeycomb core. As part of an approach to solve these problems, NASA Langley Research Center (LaRC) and Marshall Space Flight Center (MSFC) are working to develop and investigate polymer films that will act as a barrier to the permeation of LH2 through the composite laminate. In this study two commercially available films and eleven novel LaRC films were tested in an existing cryogenics laboratory at MSFC to determine the permeance of argon at room temperature. Several of these films were introduced as a layer in the composite to form an interleaved, or hybrid, composite to determine the effects on permeability. In addition, the effects of the interleaved layer thickness, number, and location on the mechanical properties of the composite laminate were investigated. In this initial screening process, several of the films were found to exhibit lower permeability to argon than the composite panels tested.