gebhart/patrepeval huggingface dataset:
Electric-field-assisted moderator for generation of intense low-energy positron beams (1998)

In this paper we reexamine an old idea of using an electric-field-assisted moderator (FAM) based on a rare-gas solid (RGS) to form intense low-energy positron beams. Contrary to common belief, the main body of a successful FAM should consist of a dirty (a high level of molecular impurities) RGS which will allow for a high ${e}^{+}$ drift velocity. On top of this layer is condensed a thin layer of a highy-purity RGS. When the ${e}^{+}$ enters this latter region its energy will heat up, and ${e}^{+}$ emission into vacuum will become possible despite a positive ${e}^{+}$ affinity of the RGS. Simple calculations show that the ${e}^{+}$ intensity can be increased by a factor of 100 over what can be achieved using a RGS moderator without an applied electric field and, equally important, the ${e}^{+}$ transverse energy is reduced to less than 0.3 eV. This leads to a gain in brightness by a factor of 1000.
Comparative structural studies of [3.1.0]-fused 2',3'-modified .beta.-D-nucleosides by x-ray crystallography, NMR spectroscopy, and molecular mechanics calculations (1991)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComparative structural studies of [3.1.0]-fused 2',3'-modified .beta.-D-nucleosides by x-ray crystallography, NMR spectroscopy, and molecular mechanics calculationsLeo H. Koole, Stephen Neidle, Mark D. Crawford, Alexander A. Krayevski, Galyna V. Gurskaya, Anders Sandstroem, Jin Chang Wu, Weimin Tong, and Jyoti ChattopadhyayaCite this: J. Org. Chem. 1991, 56, 24, 6884–6892Publication Date (Print):November 1, 1991Publication History Published online1 May 2002Published inissue 1 November 1991https://pubs.acs.org/doi/10.1021/jo00024a034https://doi.org/10.1021/jo00024a034research-articleACS PublicationsRequest reuse permissionsArticle Views143Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Signal enhancement through polarization adaptivity on transmit in a near-field MIMO environment (2005)

In this paper polarization adaptivity on transmit has been used to enhance the received signals directed to a pre-selected receiver in a near-field multi-input multi-output (MIMO) environment. The objective here is to select a set of weights on the transmitting antennas adapted to each receiver based on the principles of reciprocity. Using the polarization properties, when the number of receiving antennas is greater than the number of transmitting antennas, the transmitted signal may be directed more to a particular receiver location while simultaneously minimizing the reception signal strength at other receivers. A numerical simulation has been made to illustrate the novelty of the proposed approach.
Liver Vessels Segmentation Using a Hybrid Geometrical Moments/Graph Cuts Method (2009)

This paper describes a fast and fully automatic method for liver vessel segmentation on computerized tomography scan preoperative images. The basis of this method is the introduction of a 3-D geometrical moment-based detector of cylindrical shapes within the minimum-cut/maximum-flow energy minimization framework. This method represents an original way to introduce a data term as a constraint into the widely used Boykov's graph cuts algorithm, and hence, to automate the segmentation. The method is evaluated and compared with others on a synthetic dataset. Finally, the relevancy of our method regarding the planning of a necessarily accurate percutaneous high-intensity focused ultrasound surgical operation is demonstrated with some examples.
X-Ray Phase Imaging with Single Phase Grating (2007)

X-ray phase imaging with a single phase grating based on the fractional Talbot effect is described. A phase grating with an 8 µm pitch was placed behind a weakly absorbing object and illuminated with partially coherent 17.7 keV X-rays. Intensity patterns downstream of the grating were recorded with a high-resolution image detector. By the fringe scanning method, an X-ray wavefront inclination by the object was obtained. Phase tomography was performed and the three-dimensional structure of a piece of a polymer blend was revealed with an 8 µm spatial resolution and a 9 mg/cm3 detection limit of density deviation.
Magnetization reversal assisted by the inverse piezoelectric effect in Co-Fe-B<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo>/</mml:mo></mml:mrow></mml:math>ferroelectric multilayers (2011)

We investigate magnetization reversal assisted by electric fields in a Co${}_{40}$Fe${}_{40}$B${}_{20}/$Co$/$Pd multilayer with soft perpendicular anisotropy deposited onto an epitaxial piezoelectric layer. Both the nucleation and depinning magnetic fields show a strong reduction of up to 30$%$ under the application of an electric field. These results show good prospects for assisting the switching processes in ultra-low-power spintronic devices.
Manganese(II)-Oxidizing <i>Bacillus</i> Spores in Guaymas Basin Hydrothermal Sediments and Plumes (2006)

Microbial oxidation and precipitation of manganese at deep-sea hydrothermal vents are important oceanic biogeochemical processes, yet nothing is known about the types of microorganisms or mechanisms involved. Here we report isolation of a number of diverse spore-forming Mn(II)-oxidizing Bacillus species from Guaymas Basin, a deep-sea hydrothermal vent environment in the Gulf of California, where rapid microbially mediated Mn(II) oxidation was previously observed. mnxG multicopper oxidase genes involved in Mn(II) oxidation were amplified from all Mn(II)-oxidizing Bacillus spores isolated, suggesting that a copper-mediated mechanism of Mn(II) oxidation could be important at deep-sea hydrothermal vents. Phylogenetic analysis of 16S rRNA and mnxG genes revealed that while many of the deep-sea Mn(II)-oxidizing Bacillus species are very closely related to previously recognized isolates from coastal sediments, other organisms represent novel strains and clusters. The growth and Mn(II) oxidation properties of these Bacillus species suggest that in hydrothermal sediments they are likely present as spores that are active in oxidizing Mn(II) as it emerges from the seafloor.
Tobacco Smoke Exposure and Levels of Urinary Metals in the U.S. Youth and Adult Population: The National Health and Nutrition Examination Survey (NHANES) 1999–2004 (2009)

We assessed 12 urine metals in tobacco smoke-exposed and not exposed National Health and Nutrition Examination Survey participants. Our analysis included age, race/ethnicity, and poverty status. Gender and racial/ethnic differences in cadmium and lead and creatinine-adjusted and unadjusted data for group comparisons are presented. Smokers' had higher cadmium, lead, antimony, and barium levels than nonsmokers. Highest lead levels were in the youngest subjects. Lead levels among adults with high second-hand smoke exposure equaled smokers. Older smokers had cadmium levels signaling the potential for cadmium-related toxicity. Given the potential toxicity of metals, our findings complement existing research on exposure to chemicals in tobacco smoke.
PRODUCTION OF PARALYTIC SHELLFISH TOXINS BY <i>APHANIZOMENON</i> SP. LMECYA 31 (CYANOBACTERIA)<sup>1</sup> (2002)

We examined intracellular and extracellular paralytic shellfish toxins (PST) in a strain of Aphanizomenon sp. (LMECYA31) isolated from a Portuguese freshwater reservoir throughout the growth cycle and under different conditions affected by temperature and nitrate and phosphate availability. PST concentrations and compositions were greatly influenced by cell density, growth stage, and temperature and nutrients conditions. On a per‐cell basis results showed (1) the enhancement of PST cell quota after the end of exponential growth phase in nutrient replete batch cultures, (2) the absence of a PST increment at late growth stages under phosphate limitation, (3) a rise in PST maximum cell quota under nitrate depletion, and (4) the enhancement of toxin production at higher temperatures. The relative proportion of the four toxins detected, neoSTX, dcSTX, STX and GTX5, also changed within and between culture settings. While growing under phosphate rich media cells produced mainly GTX5 and neoSTX, whereas under phosphate limitation the proportion of STX and dcSTX increased substantially with culture age. Large amounts of extracellular toxins were found in the culture medium, increasing during culture time. Extracellular toxin composition in each culture was fairly constant and always similar to the intracellular composition found at late stages of growth. This further supported other research that indicates that PSTs are released to the water through cell lysis, and a significant concentration of PST may be expected to remain in the water upon the collapse of a toxic bloom or after cells removal by water treatment.
Surface Engineering of Metals (1998)

Surface Engineering of Metals provides basic definitions of classical and modern surface treatments, addressing mechanisms of formation, microstructure, and properties of surface layers.Part I outlines the fundamentals of surface engineering, presents the history of its development, and proposes a two-category classification of surface layers. Discussions include the basic potential and usable properties of superficial layers and coatings, explaining their concept, interaction with other properties, and the significance of these properties for proper selection and functioning.Part II provides an original classification of the production methods of surface layers. Discussions include the latest technologies in this field, characterized by directional or beam interaction of particles or of the heating medium with the treat surface.
Platelet-derived Growth Factor Receptor β Regulates Migration and DNA Synthesis in Metanephric Mesenchymal Cells (2000)

Platelet-derived growth factor (PDGF) B-chain and PDGF receptor beta (PDGFR beta) are essential for glomerulogenesis. Mice deficient in PDGF B-chain or PDGFR beta exhibit an abnormal glomerular phenotype characterized by total lack of mesangial cells. In this study, we localized PDGFR beta in the developing rat kidney and explored the biological effects of PDGF in metanephric mesenchymal cells in an attempt to determine the mechanism by which PDGF regulates mesangial cell development. Immunohistochemical and in situ hybridization studies of rat embryonic kidneys reveal that PDGFR beta localizes to undifferentiated metanephric mesenchyme and is later expressed in the cleft of the comma-shaped and S-shaped bodies and in more mature glomeruli in a mesangial distribution. We also isolated and characterized cells from rat metanephric mesenchyme. Metanephric mesenchymal cells express vimentin and alpha-smooth muscle actin but not cytokeratin. These cells also express functional PDGFR beta, as demonstrated by autophosphorylation of the receptor as well as activation of phosphatidylinositol 3 kinase in response to PDGF B-chain homodimer. PDGF B-chain also induces migration and proliferation of metanephric mesenchymal cells. Taken together with the fact that PDGF B-chain is expressed in the glomerular epithelium and mesangial area, as demonstrated in the human embryonic kidney, we suggest that PDGF B-chain acts in a paracrine fashion to stimulate the migration and proliferation of mesangial cell precursors from undifferentiated metanephric mesenchyme to the mesangial area. PDGF B-chain also likely stimulates proliferation of mesangial cell precursors in an autocrine fashion once these cells migrate to the glomerular tuft.
Transcription of the Escherichia coli rrnB P1 promoter by the heat shock RNA polymerase (E sigma 32) in vitro (1993)

The P1 promoters of the seven Escherichia coli rRNA operons contain recognition sequences for the RNA polymerase (RNAP) holoenzyme containing sigma 70 (E sigma 70), which has been shown to interact with and initiate transcription from rrn P1 promoters in vivo and in vitro. The rrn P1 promoters also contain putative recognition elements for E sigma 32, the RNAP holoenzyme responsible for the transcription of heat shock genes. Using in vitro transcription assays with purified RNAP holoenzyme, we show that E sigma 32 is able to transcribe from the rrnB P1 promoter. Antibodies specific to sigma 70 eliminate transcription of rrnB P1 by E sigma 70 but have no effect on E sigma 32-directed transcription. Physical characterization of the E sigma 32-rrnB P1 complex shows that there are differences in the interactions made by E sigma 70 and E sigma 32 with the promoter. E sigma 32 responds to both Fis-mediated and factor-independent upstream activation, two systems shown previously to stimulate rrnB P1 transcription by E sigma 70. We find that E sigma 32 is not required for two major control systems known to regulate rRNA transcription initiation at normal temperatures in vivo, stringent control and growth rate-dependent control. On the basis of the well-characterized role of E sigma 32 in transcription from heat shock promoters in vivo, we suggest that E sigma 32-directed transcription of rRNA promoters might play a role in ribosome synthesis at high temperatures.
Living in to its Name and Living up to its Legacy: The public practical theology of KAIROS (2015)

KAIROS Canada looks hopefully towards the emerging challenges of continuing public practical theology in a pluralistic, post-apology time and place.
Wafer-level micro-optics: trends in manufacturing, testing, and packaging (2011)

Micro-optics is an indispensable key enabling technology (KET) for many applications today. The important role of micro-optical components is based on three different motivations: miniaturization, high functionality and packaging aspects. It is obvious that miniaturized systems require micro-optics for light focusing, light shaping and imaging. More important for industrial applications is the high functionality of micro-optics that allows combining these different functions in one element. In DUV Lithography Steppers and Scanners an extremely precise beam shaping of the Excimer laser profile is required. High-precision diffractive optical elements are well suited for this task. For Wafer-Level Cameras (WLC) and fiber optical systems the packaging aspects are more important. Wafer-Level Micro-Optics technology allows manufacturing and packaging some thousands of sub-components in parallel. We report on the state of the art in wafer-based manufacturing, testing and packaging.
Preparation of Linear Oligoaniline Derivatives Using Titanium Alkoxide as a Condensing Agent (1994)

Abstract Linear oligoaniline derivatives were prepared by the reaction of aromatic amines and phenols using various titanium alkoxides as condensing agents. The oligomers obtained were silver white microscopic crystals. Titanium alkoxides used were titanium alkoxide or titanium alkoxide aryloxide and the latter showed high dehydration condensation activity in comparison with the usual titanium alkoxides.
Radiation characteristics of dielectric-loaded horn antennas (1970)

The radiation characteristics of electromagnetic horns loaded with curved transverse dielectric slabs and radial dielectric strips are investigated experimentally. It is shown that the axial directivity and halfpower beamwidth of horn antennas may be significantly improved with such schemes of dielectric loading.
My Lips Are Concealed: Audio-Visual Speech Enhancement Through Obstructions (2019)

Our objective is an audio-visual model for separating a single speaker from a mixture of sounds such as other speakers and background noise. Moreover, we wish to hear the speaker even when the visual cues are temporarily absent due to occlusion. To this end we introduce a deep audio-visual speech enhancement network that is able to separate a speaker's voice by conditioning on both the speaker's lip movements and/or a representation of their voice. The voice representation can be obtained by either (i) enrollment, or (ii) by self-enrollment -- learning the representation on-the-fly given sufficient unobstructed visual input. The model is trained by blending audios, and by introducing artificial occlusions around the mouth region that prevent the visual modality from dominating. The method is speaker-independent, and we demonstrate it on real examples of speakers unheard (and unseen) during training. The method also improves over previous models in particular for cases of occlusion in the visual modality.
Synthesis of 1-Benzometalloles Containing Group 14, 15, and 16 Heavier Elements via a Common Dilithiostyrene Intermediate. (1994)

The Group 14 (Si, Ge, and Sn), Group 15 (P, As, Sb, and Bi), and Group 16 (Se and Te) 2-trimethylsilyl-1-benzometalloles (7) were prepared by the reaction of the corresponding metal reagents with β, o-dilithio-β-trimethyl-silylstyrene intermediate (6), which was derived from phenylacetylene or o-bromoiodobenzene via three steps. The trimethylsilyl group in 7 could be readily removed by treatment with tetrabutylammonium fluoride to give the C-unsubstituted 1-banzometalloles (10).
Schema integration analysis for the development of GIS databases (1989)

Abstract Analysing the differences and similarities in data descriptions for two or more databases is a common and difficult task for many database development environments. This task is important whether the environment concerns a spatial data transfer process, a database design process for a multi-purpose land information system and/ or a federated group of inter-operable databases in a land information systems network. Schema integration analysis is a stage in a process of information integration undertaken to identify and reconcile differences and similarities between data descriptions. Both the structural and semantic descriptions in a schema need to be processed to identify equivalent concepts. An example of schema integration analysis is described in the context of a database of urban land parcels.
The Vitamin D–Antimicrobial Peptide Pathway and its Role in Protection Against Infection (2009)

Vitamin D deficiency has been correlated with increased rates of infection. Since the early 19th century, both environmental (i.e., sunlight) and dietary sources (cod liver) of vitamin D have been identified as treatments for TB. The recent discovery that vitamin D induces antimicrobial peptide gene expression explains, in part, the 'antibiotic' effect of vitamin D and has greatly renewed interest in the ability of vitamin D to improve immune function. Subsequent work indicates that this regulation is biologically important for the response of the innate immune system to wounds and infection and that deficiency may lead to suboptimal responses toward bacterial and viral infections. The regulation of the cathelicidin antimicrobial peptide gene is a human/primate-specific adaptation and is not conserved in other mammals. The capacity of the vitamin D receptor to act as a high-affinity receptor for vitamin D and a low-affinity receptor for secondary bile acids and potentially other novel nutritional compounds suggests that the evolutionary selection to place the cathelicidin gene under control of the vitamin D receptor allows for its regulation under both endocrine and xenobiotic response systems. Future studies in both humans and humanized mouse models will elucidate the importance of this regulation and lead to the development of potential therapeutic applications.
Radio wave diffraction from impedance surfaces with one dimensional general impedance variation (2002)

The problem of plane wave diffraction from shorelines in planar land-sea boundaries, using the Wiener-Hopf technique, was addressed by Bazer et al. (1962). Geometrical theory of diffraction (GTD) methods, while accurate at high frequencies, have only been applied to problems where abrupt variations in a surface are present. An analytical formulation is developed to predict the diffraction from a surface impedance discontinuity, of an arbitrary profile, such as rivers, shorelines, or troughs, when excited by a small dipole of arbitrary orientation. Basically the river is modeled as an impedance change in an infinite impedance plane, representing the ground plane. An integral equation is developed in the Fourier domain for ease of analysis and then solved analytically using a perturbation technique, assuming a one dimensional impedance variation. Recursive expressions for the induced current of any order, for arbitrary impedance variations, are shown. Using these currents, the far field expressions for plane wave excitation are evaluated using the stationary phase technique. The derivation is then extended to small dipole excitation represented by a continuous spectrum of plane waves, again using the stationary phase to calculate the diffracted fields. Results for both plane wave and dipole excitation are shown.
Predicting the Effect of Moisture on Vapor-Phase Sorption of Volatile Organic Compounds to Soils (1996)

Sorption from the vapor phase is an important factor controlling the transport of volatile organic compounds (VOCs) in the unsaturated zone. Accurate description of sorption from the vapor phase to soil in the unsaturated zone therefore is intrinsic to predicting the ultimate fate of contaminants. Vapor-phase sorption of several VOCs onto seven soils at oven-dried, air-dried, typical field moisture and water-saturated conditions was measured using a batch-equilibrium headspace method. An equilibrium partitioning model was developed to predict the effect of soil moisture content on vapor-phase sorption. The model was based on the soil pore-size distribution and BET isotherm sorption parameters under oven-dried and water-saturated conditions. The model was shown to accurately predict observed experimental results.
Assessment of a Model-Based, Iterative Reconstruction Algorithm (MBIR) Regarding Image Quality and Dose Reduction in Liver Computed Tomography (2013)

The HD MBIR images showed less noise, higher CNR, and better image quality than the HD ASIR and HD FBP images did; they also provided less image noise, higher CNR, and similar image quality compared with those of RD FBP images.
A Study of Textural Analysis Methods for the Diagnosis of Liver Diseases from Abdominal Computed Tomography (2013)

Liver diseases are considered seriously because liver is a vital organ to human beings. Computer aided liver analysis is a technique that can help radiologists to accurately identify diseases that can help in reducing the risk of liver surgery. The computer aided diagnosis (CAD) system consists of the segmentation of liver and lesion, extraction of features from a lesion and characterization of liver diseases by means of a classifier. In the last decade, the use of many segmentation techniques and classifier systems have been proposed by many authors with the intention to increase the performance of CAD systems This article focuses on various textural analysis methods used so far for the classification of liver diseases from abdominal Computed Tomography scans. It reviews the techniques and results of the various methods are analyzed and summarized. The future direction for the research is also discussed