gebhart/patrepeval huggingface dataset:
Development of a stress gradient enhanced piezoelectric actuator composite (GEPAC) with integrated ultrasonic NDE capablity (2003)

Stress gradient enhanced piezoelectric composites (GEPACs) are unimorph based curved actuators that can be primarily used as low-frequency actuators embedded within an aircraft skin. The actuator is made of a thin PZT ceramic bonded between two composite layers with different coefficients of thermal expansion. Actuators have been manufactured with segmented upper electrodes so that they can also be used at ultrasonic frequencies to monitor continuously the integrity of the actuator itself (cracks), or of the actuator/skin assembly (debonding). This study will focus on the detection of debonding at the interface between the piezoelectric layer and the outer layers. The input signal is a one cycle burst at 1 MHz. The time domain signals recorded experimentally are compared with predictions from a finite element model (ABAQUS explicit). It is shown that the presence of a debonding defect can convert a symmetric pulse into a primarily antisymmetric wave. A simple correlation technique is used to estimate the size of the debonding defect. The ultrasonic NDE operation superposed to the low frequency actuation is demonstrated. [Work supported by the AFOSR.]
Amino Acid Catalyzed Dynamic Kinetic Asymmetric Transformations (DYKAT): One‐Step de novo Synthesis of Polyketide Sugars from Racemic β‐Hydroxy Aldehydes. (2005)

Abstract For Abstract see ChemInform Abstract in Full Text.
Supplementary Figures from The Effect of Mouse Strain, Sex, and Carcinogen Dose on Toxicity and the Development of Lung Dysplasia and Squamous Cell Carcinomas in Mice (2023)

&lt;p&gt;Supplementary Figure S1. Gene expression in mouse SCC is consistent with human SCC data. Supplementary Figure S2. Lung non-neoplastic lesions found in animals treated with NTCU. Supplementary Figure S3. Lymphoid aggregates and PD-L1 expression in the lung of mice treated with NTCU.&lt;/p&gt;
Dynamically adaptable architecture for real-time video processing (2010)

In this paper, we present a new adaptable ring-based architecture for video processing applications. The proposed architecture allows handling pipelined and parallel organization of computation for multiple video flows. A simplified version with four nodes has been implemented on an FPGA for a video application to show the adaptation mechanism between a pipelined and parallel structure.
High-performance electrically transduced hazardous gas sensors based on low-dimensional nanomaterials (2021)

Low-dimensional nanomaterials have been proven as promising high-performance gas sensing components due to their fascinating structural, physical, chemical, and electronic characteristics. In particular, materials with low dimensionalities (<i>i.e.</i>, 0D, 1D, and 2D) possess an extremely large surface area-to-volume ratio to expose abundant active sites for interactions with molecular analytes. Gas sensors based on these materials exhibit a sensitive response to subtle external perturbations on sensing channel materials <i>via</i> electrical transduction, demonstrating a fast response/recovery, specific selectivity, and remarkable stability. Herein, we comprehensively elaborate gas sensing performances in the field of sensitive detection of hazardous gases with diverse low-dimensional sensing materials and their hybrid combinations. We will first introduce the common configurations of gas sensing devices and underlying transduction principles. Then, the main performance parameters of gas sensing devices and subsequently the main underlying sensing mechanisms governing their detection operation process are outlined and described. Importantly, we also elaborate the compositional and structural characteristics of various low-dimensional sensing materials, exemplified by the corresponding sensing systems. Finally, our perspectives on the challenges and opportunities confronting the development and future applications of low-dimensional materials for high-performance gas sensing are also presented. The aim is to provide further insights into the material design of different nanostructures and to establish relevant design guidelines to facilitate the device performance enhancement of nanomaterial based gas sensors.
Characterization of Anion Exchange Ionomers in Hybrid Polymer Electrolyte Fuel Cells (2010)

Anion exchange ionomers (AEI) synthesized here were characterized by use of a novel fuel cell configuration. The new analysis method involves assembling the AEI electrode of interest as the cathode in a hybrid, acid/alkaline, fuel cell configuration. The hybrid cell includes a conventional proton conducting anode/membrane half-cell along with the anionic conductor of interest at the cathode. Electrochemical impedance spectroscopy and voltammetry were used to evaluate the performance of the hybrid AEI-containing fuel cell with H₂ and O₂. In particular, the AEI electrode response in impedance spectroscopy was easily identified because the contributions from other components are largely minimized in the presented hybrid cell configuration. The properties of ionomers used in the AEI electrode were shown to have a substantial effect on the electrode performance. Low catalyst utilization, due to high water uptake and low conductivity, was identified as the major causes of poor performance in AEI electrodes.
Production of Non Viral DNA Vectors (2010)

After some decades of research, development and first clinical approaches to use DNA vectors in gene therapy, cell therapy and DNA vaccination, the requirements for the pharmaceutical manufacturing of gene vectors has improved significantly step by step. Even the expression level and specificity of non viral DNA vectors were significantly modified and followed the success of viral vectors. The strict separation of "viral" and "non viral" gene transfer are historic borders between scientist and we will show that both fields together are able to allow the next step towards successful prevention and therapy. Here we summarize the features of producing and modifying these non-viral gene vectors to ensure the required quality to modify cells and to treat human and animals.
High-Frequency Resonant SEPIC Converter With Wide Input and Output Voltage Ranges (2011)

This paper presents a resonant single-ended-primary-inductor-converter (SEPIC) converter and control method suitable for high frequency (HF) and very high frequency (VHF) dc-dc power conversion. The proposed design provides high efficiency over a wide input and output voltage range, up-and-down voltage conversion, small size, and excellent transient performance. In addition, a resonant gate drive scheme is presented that provides rapid startup and low-loss at HF and VHF frequencies. The converter regulates the output using an ON-OFF control scheme modulating at a fixed frequency (170 kHz). This control method enables fast transient response and efficient light-load operation while providing controlled spectral characteristics of the input and output waveforms. A hysteretic override technique is also introduced which enables the converter to reject load disturbances with a bandwidth much greater than the modulation frequency, limiting output voltage disturbances to within a fixed value. An experimental prototype has been built and evaluated. The prototype converter, built with two commercial vertical MOSFETs, operates at a fixed switching frequency of 20 MHz, with an input voltage range of 3.6-7.2 V, an output voltage range of 3-9 V, and an output power rating of up to 3 W. The converter achieves higher than 80% efficiency across the entire input voltage range at nominal output voltage and maintains good efficiency across the whole operating range.
Characterization of a Ceria Thick Film Type Gas Sensor For Hydrogen Detection in Vacuum or Anoxic Conditions. (2018)

Detection of trace amounts of hydrogen in vacuum conditions is essential in reusable space transportation systems and for safety control in manned space exploration. We evaluated the H2 detection in vacuum conditions by a novel gas sensor using sintered ceria (cerium oxide) nanoparticles. The results show that sensor resistance depended on H2 and O2 partial pressure ratios at any pressure from 10-5 Pa to atmospheric pressure. We conclude that the ceria resistance does not depend on total pressure but on H2 and O2 adsorption. The increase in sensor resistance resulted from a decrease in oxygen vacancies dependent on the O2 storage of ceria at a high O2 partial pressure. On the other hand, H2 dissociated and formed a cluster with ceria oxygen atoms when the H2 partial pressure was higher than the O2 partial pressure. Sensor resistance markedly decreased in these conditions because Ce3+ with free electrons were generated. In summary, the proposed sensor can convert gas adsorption into an electrical signal even in vacuum or anoxic conditions, and has the potential to be a highly durable device with high sensitivity.
Simulating a Communication System (2021)

This chapter looks at the basics of simulation of communication systems, covering topics such as strategy, modeling, general methodology, link and network-level categorization, error sources, performance evaluation, and practical issues. It focuses on some of the critical questions regarding the choices concerning a simulation setup. The chapter discusses the strategies that can be opted for when developing such a system. It provides the general steps to follow in solving any problem using a simulation approach. The chapter also provides a summary of the different levels of modeling that make up a simulation and a brief description of the different blocks that constitute a typical communication link from the simulation perspective. Code snippets for different blocks of the communication system are provided considering the selected case study, i.e. communication in the presence of an additive white Gaussian noise. The chapter describes network layout generation and some popular methods for it.
Hairy cell leukemia, a B-cell neoplasm that is particularly sensitive to the cytotoxic effect of anti-Tac(Fv)-PE38 (LMB-2). (2000)

Anti-Tac(Fv)-PE38 (LMB-2) is a recombinant, single-chain immunotoxin composed of the variable domains of the anti-Tac (anti-CD25) monoclonal antibody fused to a truncated form of Pseudomonas exotoxin (PE). Until now, this agent has been reported to be very cytotoxic toward T-cell but not B-cell leukemic cells freshly obtained from patients and is being tested clinically in patients with CD25+ malignancies of both B- and T-cell origin. Hairy cell leukemia (HCL) is a B-cell malignancy in which the cells are usually CD25+ and their ex vivo sensitivity to LMB-2 was unknown. Malignant cells from the first HCL patient to be tested were very sensitive to the cytotoxic effect of LMB-2 in vitro (IC50, 1.1 ng/ml), and this patient responded clinically to LMB-2 administered systemically. Therefore, we decided to assess the potential clinical utility of LMB-2 in other patients with HCL. We tested fresh leukemic cells from nine additional CD25+ HCL patients. LMB-2 was very cytotoxic ex vivo in all patients with IC50s as low as 0.5 ng/ml. Malignant cells freshly obtained from patients with chronic lymphocytic leukemia were also sensitive to LMB-2 but not as sensitive as cells from HCL patients. These results indicate that CD25+ HCL is a B-cell neoplasm that is particularly sensitive to LMB-2, and this agent may be useful in patients who have failed standard therapies.
Bit-map based resource partitioning in LTE-A femto deployment (2013)

Self organizing network techniques are needed to manage serious two-tier interference in an ad hoc operation of dense femtocell deployment. This paper considers downlink frequency domain inter-cell interference coordination (ICIC) in femtocell deployment. The studied resource partitioning method works such that each active femtocell may adapt, determine, and advertise a so-called binary resource partition sequence indicating which physical resource blocks (PRBs) the femtocells may occupy for their current operation. The main idea is to avoid interference from neighbor femto access points (FAPs) and try to achieve guaranteed bit-rate to femto users. The considered coordination method requires only low rate, infrequent updates in stationary phase and enables ICIC in distributed self organizing manner. The resource partitioning strategies are simulated in an LTE compliant system level simulator. The system level results show that different resource partitioning methods provide substantial gain when MRC receiver is used. When LMMSE receiver is used gains are smaller but at least one of the resource partitioning methods provided a gain over the case without ICIC. Furthermore, it is shown that proposed method works in two different femto environments.
SiC Field Effect Transistor Technology Demonstrating Prolonged Stable Operation at 500 °C (2007)

While there have been numerous reports of short-term transistor operation at 500 °C or above, these devices have previously not demonstrated sufficient long-term operational durability at 500 °C to be considered viable for most envisioned applications. This paper reports the development of SiC field effect transistors capable of long-term electrical operation at 500 °C. A 6H-SiC MESFET was packaged and subjected to continuous electrical operation while residing in a 500 °C oven in oxidizing air atmosphere for over 2400 hours. The transistor gain, saturation current (IDSS), and on-resistance (RDS) changed by less than 20% from initial values throughout the duration of the biased 500 °C test. Another high-temperature packaged 6H-SiC MESFET was employed to form a simple one-stage high-temperature low-frequency voltage amplifier. This single-stage common-source amplifier demonstrated stable continuous electrical operation (negligible changes to gain and operating biases) for over 600 hours while residing in a 500 °C air ambient oven. In both cases, increased leakage from annealing of the Schottky gate-to-channel diode was the dominant transistor degradation mechanism that limited the duration of 500 °C electrical operation.
Deep-Reinforcement Learning Multiple Access for Heterogeneous Wireless Networks (2019)

This paper investigates a deep reinforcement learning (DRL)-based MAC protocol for heterogeneous wireless networking, referred to as a Deep-reinforcement Learning Multiple Access (DLMA). Specifically, we consider the scenario of a number of networks operating different MAC protocols trying to access the time slots of a common wireless medium. A key challenge in our problem formulation is that we assume our DLMA network does not know the operating principles of the MACs of the other networks-i.e., DLMA does not know how the other MACs make decisions on when to transmit and when not to. The goal of DLMA is to be able to learn an optimal channel access strategy to achieve a certain pre-specified global objective. Possible objectives include maximizing the sum throughput and maximizing α-fairness among all networks. The underpinning learning process of DLMA is based on DRL. With proper definitions of the state space, action space, and rewards in DRL, we show that DLMA can easily maximize the sum throughput by judiciously selecting certain time slots to transmit. Maximizing general α-fairness, however, is beyond the means of the conventional reinforcement learning (RL) framework. We put forth a new multi-dimensional RL framework that enables DLMA to maximize general α-fairness. Our extensive simulation results show that DLMA can maximize sum throughput or achieve proportional fairness (two special classes of α-fairness) when coexisting with TDMA and ALOHA MAC protocols without knowing they are TDMA or ALOHA. Importantly, we show the merit of incorporating the use of neural networks into the RL framework (i.e., why DRL and not just traditional RL): specifically, the use of DRL allows DLMA (i) to learn the optimal strategy with much faster speed and (ii) to be more robust in that it can still learn a near-optimal strategy even when the parameters in the RL framework are not optimally set.
Integrating security in a group oriented distributed system (2003)

A distributed security architecture is proposed for incorporation into group oriented distributed systems, and in particular, into the Isis distributed programming toolkit. The primary goal of the architecture is to make common group-oriented abstractions robust in hostile settings in order to facilitate the construction of high-performance distributed applications that can tolerate both component failure and malicious attacks. These abstractions include process groups and causal group multicast. A delegation and access control scheme is also proposed for use in group-oriented systems. The focus is on the security architecture; particular cryptosystems and key exchange protocols are not emphasized.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
Studies on the Biosynthesis of the Notoamides: Synthesis of an Isotopomer of 6-Hydroxydeoxybrevianamide E and Biosynthetic Incorporation into Notoamide J (2011)

6-Hydroxydeoxybrevianamide E is proposed as a biosynthetic precursor to several advanced metabolites isolated from both marine-derived Aspergillus sp. and a terrestrial-derived Aspergillus versicolor. To verify the role of this reverse-prenylated indole alkaloid as an intermediate along the biosynthetic pathway, [(13)C](2)-[(15)N]-6-hydroxydeoxybrevianamide E was synthesized and fed to Aspergillus versicolor. Analysis of the metabolites showed incorporation of the intermediate only into the natural product notoamide J.
High-resolution promoter map of human limbal epithelial cells cultured with keratinocyte growth factor and rho kinase inhibitor (2017)

An in vitro model of corneal epithelial cells (CECs) has been developed to study and treat corneal disorders. Nevertheless, conventional CEC culture supplemented with epidermal growth factor (EGF) results in a loss of CEC characteristics. It has recently been reported that limbal epithelial cells (LECs) cultured with keratinocyte growth factor (KGF) and the rho kinase inhibitor Y-27632 could maintain the expression of several CEC-specific markers. However, the molecular mechanism underlying the effect of culture media on LECs remains to be elucidated. To elucidate this mechanism, we performed comprehensive gene expression analysis of human LECs cultured with EGF or KGF/Y-27632, by cap analysis of gene expression (CAGE). Here, we found that LECs cultured with KGF and Y-27632 presented a gene expression profile highly similar to that of CECs in vivo. In contrast, LECs cultured with EGF lost the characteristic CEC gene expression profile. We further discovered that CEC-specific PAX6 promoters are highly activated in LECs cultured with KGF and Y-27632. Our results provide strong evidence that LECs cultured with KGF and Y-27632 would be an improved in vitro model in the context of gene expression. These findings will accelerate basic studies of CECs and clinical applications in regenerative medicine.
Elastomeric Structural Attachment Concepts for Aircraft Flap Noise Reduction - Challenges and Approaches to Hyperelastic Structural Modeling and Analysis (2014)

Airframe noise is a significant part of the overall noise of transport aircraft during the approach and landing phases of flight. Airframe noise reduction is currently emphasized under the Environmentally Responsible Aviation (ERA) and Fixed Wing (FW) Project goals of NASA. A promising concept for trailing-edge-flap noise reduction is a flexible structural element or link that connects the side edges of the deployable flap to the adjacent main-wing structure. The proposed solution is distinguished by minimization of the span-wise extent of the structural link, thereby minimizing the aerodynamic load on the link structure at the expense of increased deformation requirement. Development of such a flexible structural link necessitated application of hyperelastic materials, atypical structural configurations and novel interface hardware. The resulting highly-deformable structural concept was termed the FLEXible Side Edge Link (FLEXSEL) concept. Prediction of atypical elastomeric deformation responses from detailed structural analysis was essential for evaluating feasible concepts that met the design constraints. The focus of this paper is to describe the many challenges encountered with hyperelastic finite element modeling and the nonlinear structural analysis of evolving FLEXSEL concepts. Detailed herein is the nonlinear analysis of FLEXSEL concepts that emerged during the project which include solid-section, foamcore, hollow, extended-span and pre-stressed concepts. Coupon-level analysis performed on elastomeric interface joints, which form a part of the FLEXSEL topology development, are also presented.
In Vivo Selection of Phage for the Optical Imaging of PC-3 Human Prostate Carcinoma in Mice (2006)

There is an increasing medical need to detect and spatially localize early and aggressive forms of prostate cancer. Affinity ligands derived from bacteriophage (phage) library screens can be developed to molecularly target prostate cancer with fluorochromes for optical imaging. Toward this goal, we used in vivo phage display and a newly described micropanning assay to select for phage that extravasate and bind human PC-3 prostate carcinoma xenografts in severe combined immune deficiency mice. One resulting phage clone (G1) displaying the peptide sequence IAGLATPGWSHWLAL was fluorescently labeled with the near-infrared fluorophore AlexaFluor 680 and was evaluated both in vitro and in vivo for its ability to bind and target PC-3 prostate carcinomas. The fluorescently labeled phage clone (G1) had a tumor-to-muscle ratio of approximately 30 in experiments. In addition, prostate tumors (PC-3) were readily detectable by optical-imaging methods. These results show proof of principle that disease-specific library-derived fluorescent probes can be rapidly developed for use in the early detection of cancers by optical means.
Boundary feature extraction from gray-scale document images (2002)

A novel method is presented for extracting closed boundaries of document components such as characters and symbols directly from gray-scale document images based on the surface data structures along with structural features. The method is based on the simple model assuming that a closed boundary of document components can be approximated as a series of horizontal line segments and can be extracted by linking surface components with steep gradients which share commonly intersecting horizontal planes. The proposed algorithm is compared with some binarization algorithms, shown to be effective for improving recognition accuracy for very poor quality data.
Low complexity margin adaptive resource allocation in downlink MIMO-OFDMA system (2009)

We study the downlink multiuser Multiple Input Multiple Output-Orthogonal Frequency Division Multiple Access (MIMO-OFDMA) system for margin adaptive resource allocation where the base station (BS) has to satisfy individual quality of service (QoS) constraints of the users subject to transmit power minimization. Low complexity solutions involve beamforming techniques for multiuser inter-stream interference cancellation. However, when beamforming is introduced in the margin adaptive objective, it becomes a joint beamforming and resource allocation problem. We propose a sub-optimal two-step solution which decouples beamforming from subcarrier and power allocation. First a reduced number of user groups are formed and then the problem is formulated as a convex optimization problem. Finally an efficient algorithm is developed which allocates the best user group to each subcarrier. Simulation results reveal comparable performance with the hugely complex optimal solution.