gebhart/patrepeval huggingface dataset:
Micron accurate deployable antenna and sensor technology for new-millennium-era spacecraft (2002)

This paper summarizes recent results in a cooperative research program between the University of Colorado and NASA Langley Research Center in the deployment of precise antennas and reflectors from compact spacecraft. Advances in concepts, joints, materials, ground-test methodology, and micro-structural mechanics are presented which demonstrate the potential for passively positioning deployed components to within a few microns of their desired configuration. This technology promises to advance the state-of-the-art in deployment technology by several orders of magnitude in the next five to ten years. This means it will be possible to deploy reflectors with passive diffraction limited performance up to long wave infrared frequencies with a mass of perhaps five kilograms per square meter. Results of a ground test validation program and a planned flight validation experiment are presented to illustrate the key technical results of this research.
ArcSAR: Theory, Simulations, and Experimental Verification (2016)

ArcSAR is a ground-based synthetic aperture radar (GBSAR) that has recently been receiving increasing interest in the scientific literature. While the conventional GBSAR exploits the movement of an antenna along a linear rail to synthesize a large aperture, an ArcSAR exploits the spatial diversity of the data acquired by an antenna fixed to a rotating arm. The great advantage of ArcSAR is its capability to synthesize images at 360° with a constant resolution in azimuth. In this paper, the authors propose and test a new focusing algorithm that does not require to operate in the far field and neither with narrow beam antennas; moreover, it is flexible enough to focus on any plane (not necessarily on the rotation plane) as well as in the whole 3-D space. Furthermore, the authors demonstrate theoretically and experimentally that ArcSAR images can be affected by a “defocusing effect” of the targets far from the rotation plane, which has to be taken into consideration when designing such radars.
X-ray spectrograph design (1983)

An aberration theory is applied to spectrograph design. The initial system considered has a toroidal mirror in front of a concave grating spectrograph, giving spatial resolution perpendicular to the dispersion direction. The accuracy of the theory is shown by comparison of spot diagrams obtained from the aberrations with those produced by raytracing. The major aberrations affecting the vignetting at the intermediate slit and the spatial resolution are identified. A new system, using a holographic grating to give a flat focal plane, is then designed and optimized. It has increased spatial resolution over the wavelength range and is particularly suitable for microchannel array detectors.
The Stereochemical Basis of Template Function (1977)

The behavior of nucelotides with thioketo-substituted pyrimidine bases (4-thiouracil, 2-thiouracil and 2-thiocytosine) or amino-analogue purine bases (2-aminopurine and 2,6-diaminopurine) in transcription and translation was investigated. The experimental results obtained led to the following conclusions. 1. The stereochemical basis of substrate selection in transcription is the geometry of Watson-Crick base pairs A-U (or A-T) and G-C between substrate and template bases. 2. The topology of the active site of Escherichia coli RNA polymerase is precisely adopted to the geometry of Watson-Crick base pairs. 3. The enzyme active site discriminates between A-U (A-T) and G-C base pairs. An essential feature in this discrimination is the 6-NH2 group of the A-U (A-T) base pair and the 2-keto group of cytosine in the G-C base pair. 4. The codon properties of a nucleic acid base in messenger RNA can be predicted on the basis of its specificity in polynucleotide interactions. There seems to be no evidence for the participation of protein topological sites in the control of the specificity of codon-anticodon interactions in translation.
Stagnation points control chaotic fluctuations in viscoelastic porous media flow (2021)

Viscoelastic flows through porous media become unstable and chaotic beyond critical flow conditions, impacting widespread industrial and biological processes such as enhanced oil recovery and drug delivery. Understanding the influence of the pore structure or geometry on the onset of flow instability can lead to fundamental insights into these processes and, potentially, to their optimization. Recently, for viscoelastic flows through porous media modeled by arrays of microscopic posts, Walkama et al. [D. M. Walkama, N. Waisbord, J. S. Guasto, <i>Phys. Rev. Lett</i> 124, 164501 (2020)] demonstrated that geometric disorder greatly suppressed the strength of the chaotic fluctuations that arose as the flow rate was increased. However, in that work, disorder was only applied to one originally ordered configuration of posts. Here, we demonstrate experimentally that, given a slightly modified ordered array of posts, introducing disorder can also promote chaotic fluctuations. We provide a unifying explanation for these contrasting results by considering the effect of disorder on the occurrence of stagnation points exposed to the flow field, which depends on the nature of the originally ordered post array. This work provides a general understanding of how pore geometry affects the stability of viscoelastic porous media flows.
Cover Picture: Macromol. Rapid Commun. 2/2005 (2005)

Cover: The first direct organocatalytic ring‐opening polymerization from cellulose fibers is presented. The synthesis was based on organocatalytic bulk ring‐opening polymerization (ROP) of ε ‐caprolactone with cellulose cotton fiber and filter paper as the initiators. Organic acid catalysis provides a new method for the synthesis of valuable nanomaterials as well as polyesters for biomedical applications. Further details can be found in the Communication by J. Hafrén * and A. Córdova * on page 82.
A solution for SLAM through augmenting vision and range information (2008)

This paper proposes a method for augmenting the information of a monocular camera and a range finder. This method is a valuable step towards solving the SLAM problem in unstructured environments free from problems of using encoderspsila data. Proposed algorithm causes the robot to benefit from a feature-based map for filtering purposes, while it exploits an accurate motion model, based on point-wise raw range scan matching rather than unreliable feature-based range scan matching, in unstructured environments. Moreover, robust loop closure detection procedure is the other consequence of this method. Experiments with a low-cost IEEE 1394 webcam and a range finder illustrate the effectiveness of the proposed method in drift-free SLAM at loop closing motions in unstructured environments.
Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor (2018)

The bacterial intracellular second messenger, cyclic dimeric GMP (c-di-GMP), regulates biofilm formation for many bacteria. The binding of c-di-GMP by the inner membrane protein LapD controls biofilm formation, and the LapD receptor is central to a complex network of c-di-GMP-mediated biofilm formation. In this study, we examine how c-di-GMP signaling specificity by a diguanylate cyclase (DGC), GcbC, is achieved via interactions with the LapD receptor and by small ligand sensing via GcbC's <u>ca</u>lcium channel <u>che</u>motaxis (CACHE) domain. We provide evidence that biofilm formation is stimulated by the environmentally relevant organic acid citrate (and a related compound, isocitrate) in a GcbC-dependent manner through enhanced GcbC-LapD interaction, which results in increased LapA localization to the cell surface. Furthermore, GcbC shows little ability to synthesize c-di-GMP in isolation. However, when LapD is present, GcbC activity is significantly enhanced (~8-fold), indicating that engaging the LapD receptor stimulates the activity of this DGC; citrate-enhanced GcbC-LapD interaction further stimulates c-di-GMP synthesis. We propose that the I-site of GcbC serves two roles beyond allosteric control of this enzyme: promoting GcbC-LapD interaction and stabilizing the active conformation of GcbC in the GcbC-LapD complex. Finally, given that LapD can interact with a dozen different DGCs of <i>Pseudomonas fluorescens</i>, many of which have ligand-binding domains, the ligand-mediated enhanced signaling via LapD-GcbC interaction described here is likely a conserved mechanism of signaling in this network. Consistent with this idea, we identify a second example of ligand-mediated enhancement of DGC-LapD interaction that promotes biofilm formation.<b>IMPORTANCE</b> In many bacteria, dozens of enzymes produce the dinucleotide signal c-di-GMP; however, it is unclear how undesired cross talk is mitigated in the context of this soluble signal and how c-di-GMP signaling is regulated by environmental inputs. We demonstrate that GcbC, a DGC, shows little ability to synthesize c-di-GMP in the absence of its cognate receptor LapD; GcbC-LapD interaction enhances c-di-GMP synthesis by GcbC, likely mediated by the I-site of GcbC. We further show evidence for a ligand-mediated mechanism of signaling specificity via increased physical interaction of a DGC with its cognate receptor. We envision a scenario wherein a "cloud" of weakly active DGCs can increase their activity by specific interaction with their receptor in response to appropriate environmental signals, concomitantly boosting c-di-GMP production, ligand-specific signaling, and biofilm formation.
Adaptive Thermal Management for 3D ICs with Stacked DRAM Caches (2017)

We describe an adaptive thermal management system for 3D-ICs with stacked DRAM cache memories. We present a detailed analysis of the impact of 3D-IC hotspot aggregation on the refresh behavior of the stacked DRAM-based L3 cache. We also present the consequence of the refresh variation on the overall system performance and cache energy consumption. Our analysis demonstrates that memory intensive applications are influenced more strongly by the DRAM refresh variation. We show that there is an optimal operating point where, with a reduced clock frequency, processor cores would actually recover any performance loss induced by DRAM refresh and at the same time the cache energy consumption could be optimized. We propose a low overhead run-time method that can identify the best CPU frequency modulation factor to cool the system to minimize accelerated refresh rates in the DRAM caches. Our system can provide a customizable trade-off between performance of the processor and energy savings of the memory.
STEEL JACKETING OF BRIDGE COLUMNS FOR ENHANCED FLEXURAL PERFORMANCE (1990)

A theoretical and experimental program investigating the enhancement of flexural ductility by placing steel jackets around the potential plastic hinge regions of concrete columns is described. It is shown that circular and rectangular columns with inadequate detailing can be made to exhibit stable flexural response at high displacement ductility levels when confronted by steel jackets.
pUCL287 plasmid from<i>Tetragenococcus halophila</i>(<i>Pediococcus halophilus</i>) ATCC 33315 represents a new theta-type replicon family of lactic acid bacteria (1995)

A cryptic plasmid, pUCL287, was isolated from Tetragenococcus halophila (Pediococcus halophilus) ATCC 33315. It had a theta-type mechanism of replication in its natural host. Its minimal replicon, Rep287, was isolated on a 1.6-kb EcoRI fragment. The Rep287 host range included the genera Pediococcus, Enterococcus, Lactobacillus and Leuconostoc but not genus Lactococcus. Plasmids hybridizing to pUCL287 are rare among lactic acid bacteria. As assessed by hybridization, Rep287 is dissimilar to pAM beta 1, pIP501 and pUCL22, representatives of the most common theta-type replicon groups in Gram-positive bacteria. Therefore, pUCL287 appears to represent a new theta-type replicon family from lactic acid bacteria.
Injectable Self‐Healing Natural Biopolymer‐Based Hydrogel Adhesive with Thermoresponsive Reversible Adhesion for Minimally Invasive Surgery (2021)

Abstract Biocompatible hydrogel adhesives with multifunctional properties, including injectability, fast self‐healing, and suitable on‐demand detachment, are highly desired for minimally invasive procedures, but such materials are still lacking. Herein, an injectable self‐healing biocompatible hydrogel adhesive with thermoresponsive reversible adhesion based on two extracellular matrix‐derived biopolymers, gelatin and chondroitin sulfate, is developed to be used as a surgical adhesive for sealing or reconnecting ruptured tissues. The resulting hydrogels present good self‐healing and can be conveniently injected through needles. The strong tissue adhesion at physiological temperatures originates from the Schiff base and hydrogen bonding interactions between the hydrogel and tissue that can be weakened at low temperatures, thereby easily detaching the hydrogel from the tissue in the gelation state. In vivo and ex vivo rat model show that the adhesives can effectively seal bleeding wounds and fluid leakages in the absence of sutures or staples. Specifically, a proof of concept experiment in a damaged rat liver model demonstrates the ability of the adhesives to act as a suitable laparoscopic sealant for laparoscopic surgery. Overall, the adhesive has several advantages, including low cost and ease of production and application that make it an exceptional multifunctional tissue adhesive/sealant, effective in minimally invasive surgical applications.
Thermal Behavior, Stability, and Decomposition Mechanism of Poly(<i>N</i>-vinylimidazole) (2012)

Homo- and copolymers of N-vinylimidazole belong to a rapidly emerging class of polymeric materials. Because of the fact that these materials can be utilized in several high-temperature processes and applications, such as catalysis, fuel cells, polymeric ionic liquids (PIL), precursors for new materials by thermolysis, etc., and because fundamental details on the thermal behavior of such polymers are lacking, systematic investigations have been carried out to reveal the stability and the mechanism of thermal decomposition of poly(N-vinylimidazole) (PVIm) by using a variety of techniques, such as differential scanning calorimetry (DSC), thermogravimetry (TG), thermogravimetry–mass spectrometry (TG-MS), and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The investigated PVIm was obtained by free radical polymerization initiated by AIBN in benzene at 70 °C. By the unique combination of the applied methods to investigate the thermal decomposition mechanism of PVIm, it was found that the thermal decomposition of PVIm takes place in one main step in the temperature range 340–500 °C. An initial mass loss of 4% occurs before the main endothermic decomposition step due to the evaporation of water and acetone physically bound to the polymer during purification. The major products of the thermal decomposition of PVIm are 1H-imidazole and 1-vinylimidazole accompanied by several minor products, such as benzene and several alkyl aromatics. The relative ratios between imidazoles and aromatics, i.e., the 2 orders of higher amounts of imidazoles, indicate that in contrast to other polymers with heteroatom pendant groups, e.g., poly(vinyl chloride) (PVC), poly(vinyl acetate), (PVAc) and poly(vinyl alcohol) (PVA), not zip-elimination of 1H-imidazole but homolytic scission of the carbon–nitrogen bond is the main reaction of its formation. 1-Vinylimidazole is formed by main chain scission followed by depolymerization. Both 1H-imidazole and 1-vinylimidazole formation lead in part to macroradicals and short conjugated double bond sequences (polyenes) in the chain, the thermolytic cyclization, isomerization, and aromatization of which result in the low amounts of aromatics. These findings served for the basis of formulating the mechanism of the thermal decomposition of PVIm, which can be utilized in the course of further investigations with this unique polymer.
Evaluation of organic perovskite photoconductors for x-ray imaging detectors (2017)

Research over organic perovskites for light harvesting gained the momentum in past decades. Due to the convenient low temperature and uniform deposition over large area these materials are being tested for the vitality in various light harvesting devices such as in solar cells, X-ray detectors, gamma photon captures etc., On meeting the expectation, the power conversion efficiency in these devices peaked above 20% in around four years of research. But the underlying physics in these materials remains a mystery particularly that which concerns the undesirable high dark currents and photo gains when illuminated with X-ray for medical imaging.
In this thesis, the x-ray sensitivity of perovskite photoconductors under different detector operating conditions has been identified. The primary mechanism that regulates the photocurrent and dark current behavior of X-ray imagers based on organic perovskite photoconductors has been identified. Energy level misalignments between different layers of X-ray imagers leading an injective photo-gain has been investigated. The signal spreading due to trapping, k-fluorescence generation and reabsorption, pixel aperture and primary charge interaction with photoconductor has been accounted by calculating the theoretical MTF for different spatial frequency. These imaging performances are also explored by calculating the theoretical Detective Quantum Efficiency (DQE) at zero spatial frequency. Proceeding further, numerical investigation of organic perovskite had also been accounted to visualize the electric field profiles along the thickness of photoconductor. All possible recombination mechanisms and traps are included in the numerical solution of continuity, trap, and Poisson's equations simultaneously. Sensitivity reduction due to repeated exposure (Ghosting) has been investigated. A variation of electric field profile under different exposure levels has been noticed. It becomes evident that significant deviations between the analytical and numerical approaches were noticed under high exposure levels. This is due to the significant variation of electric field profiles under very high exposures. The work in this thesis identifies the important factors such as the need for appropriate blocking contacts for low dark currents, improved carrier transport properties in perovskite films and proper energy level alignment between different layers of photodetector in order to make successful perovskite x-ray detectors.
Studying Chinese Characters in a Web-Based Learning Environment: A Case Study of Swedish University Students (2020)

This survey study aims to investigate the perceptions learners have of the character-learning strategies they employ when taking a web-based course in Chinese. The seven Likert-scale statements are included in the questionnaire to examine learners’ opinions on the three character-learning strategies that are widely used in traditional campus courses. A total of 65 students who completed the beginner level ‘Chinese Characters’ web-based course at a university in Sweden completed the survey. The results suggest that students in web-based courses consider these three strategies to be just as helpful and effective as campus students; moreover, the more orthodox strategy – rote learning – is found to be the most popular among distance students. Furthermore, findings of this study provide insight into the limitations and advantages associated with a web-based course, and also the possible effect learners’ age and gender may have on learning strategy preferences.
The Fashion IQ Dataset: Retrieving Images by Combining Side Information and Relative Natural Language Feedback. (2019)

Conversational interfaces for the detail-oriented retail fashion domain are more natural, expressive, and user friendly than classical keyword-based search interfaces. In this paper, we introduce the Fashion IQ dataset to support and advance research on interactive fashion image retrieval. Fashion IQ is the first fashion dataset to provide human-generated captions that distinguish similar pairs of garment images together with side-information consisting of real-world product descriptions and derived visual attribute labels for these images. We provide a detailed analysis of the characteristics of the Fashion IQ data, and present a transformer-based user simulator and interactive image retriever that can seamlessly integrate visual attributes with image features, user feedback, and dialog history, leading to improved performance over the state of the art in dialog-based image retrieval. We believe that our dataset will encourage further work on developing more natural and real-world applicable conversational shopping assistants.
Immobilised phosphines incorporating the chiral biopolymers chitosan and chitin (1994)

W. Henderson, G. M. Olsen and L. S. Bonnington, J. Chem. Soc., Chem. Commun., 1994, 1863 DOI: 10.1039/C39940001863
Wound size measurement of lower extremity ulcers using segmentation algorithms (2016)

Lower extremity ulcers are one of the most common complications that not only affect many people around the world but also have huge impact on economy since a large amount of resources are spent for treatment and prevention of the diseases. Clinical studies have shown that reduction in the wound size of 40% within 4 weeks is an acceptable progress in the healing process. Quantification of the wound size plays a crucial role in assessing the extent of healing and determining the treatment process. To date, wound healing is visually inspected and the wound size is measured from surface images. The extent of wound healing internally may vary from the surface. A near-infrared (NIR) optical imaging approach has been developed for non-contact imaging of wounds internally and differentiating healing from non-healing wounds. Herein, quantitative wound size measurements from NIR and white light images are estimated using a graph cuts and region growing image segmentation algorithms. The extent of the wound healing from NIR imaging of lower extremity ulcers in diabetic subjects are quantified and compared across NIR and white light images. NIR imaging and wound size measurements can play a significant role in potentially predicting the extent of internal healing, thus allowing better treatment plans when implemented for periodic imaging in future.
Histone antibodies in systemic lupus erythematosus. A possible diagnostic tool (1982)

Antibodies to total histones and histone fractions H1, H2a-H4, H2b, and H3 were measured in serum samples from 61 patients with systemic lupus erythematosus (SLE), 33 with rheumatoid arthritis, 17 with systemic sclerosis, and 20 with various other diseases by use of a sensitive immunoenzymatic assay. Histone antibodies were present in 52.4% of the SLE samples whereas only 1 of the samples from other diseases was positive (systemic sclerosis). The presence of these antibodies in SLE patients was not associated with any specific clinical manifestations, but was correlated with activity of the disease: 87% (20 of 23) of patients with active SLE, in particular 9 of 9 not yet treated, showed histone antibody whereas only 18% (4 of 22) of samples from patients with inactive SLE were positive. We believe that the measurement of histone antibodies would be a useful addition to the present laboratory parameters (antinuclear and double-stranded DNA antibodies and circulating immune complexes) for the diagnosis and progression of systemic lupus erythematosus, particularly since they seem to appear during or just before the onset of an active phase and tend to be absent during remission.
Thin layer chromatography as a tool for reaction optimisation in microwave assisted synthesis (2000)

Reaction parameters for the microwave assisted synthesis of N′-substituted arylpiperazines were optimised via their rapid synthesis on thin layer chromatography (TLC) plates.