gebhart/patrepeval huggingface dataset:
Family of Compact Schmidt-Cassegrain Telescope Designs (1974)

Get PDF Email Share Share with Facebook Share on X Post on reddit Share with LinkedIn Add to Mendeley Add to BibSonomy Share with WeChat Get Citation Copy Citation Text R. D. Sigler, "Family of Compact Schmidt-Cassegrain Telescope Designs," Appl. Opt. 13, 1765-1766 (1974) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article
Modeling adsorption of cane sugar colorant in packed-bed ion exchangers (2002)

The removal of cane sugar solution colorant by packed-bed ion exchangers was modeled using a linear driving force (LDF) adsorption model. Adsorption of colorant is of interest to the developers of the White Sugar Mill (WSM) process as it is a complex subject. The problem is that color is an indiscrete mixture of many components making it difficult to measure and even more challenging to model. Colorant formation was investigated using gel permeation chromatography (GPC) with the objective of developing a method to define pseudo-components representative of cane sugar solution colorants. WSM is a process for producing white sugar directly from sugarcane in the raw sugar mill by using ultrafiltration and continuous ion exchange technology. The ion exchange resins employed were a strong acid cation (SAC) resin in the hydrogen form, a weak base anion (WBA) resin in the hydroxide form and a decolorizing resin in the chloride form. Decolorization using the three resins was then analyzed using the GPC pseudo-component technique. Batch testing of the resin allowed the development of equilibrium isotherms that could be substituted into a standard LDF model. Column testing was then performed to investigate the dynamics of adsorption of colorant in packed-beds. Linear isotherms were measured for each of the three resins, indicating that the colorant is dilute. Results indicated that a plug-flow model with a constant linear isotherm was sufficient in all cases except the SAC resin. The SAC adsorption parameter decreased sharply as the pH increased, causing colorant to be desorbed from the resin. This situation must be avoided if optimal decolorization is to be achieved. The adsorption models can be utilized in the design of a WSM process to optimize the decolorizing capacity of the resins.
Calidad del profesor y los procesos académicos: reflexiones en torno a la formación del profesorado universitario y la calidad de la enseñanza. (2001)

This paper offers an interesting reflection on the link between the quality of higher education academicians, their training and the academic processes associated to student learning. The author presents unresolved dualities and trends that somehow lead us to think on the need to acknowledge and become more aware of the importance of learning over and above teaching. The study emphasizes the importance of developing stable levels of awareness to improve the management of the academician's own academic resources. Apparently, students are somehow better prepared than teachers think to assess teacher quality in the class-room Perhaps the key lies in achieving consistency between what we are seeking for ourselves in terms of higher education teaching quality and the quality of learning achieved by our students.
Synthesis and Characterization of Gallium Oxide Nanostructures via a Soft-Chemistry Route (2007)

Nano- to microsized gallium oxide was prepared with and without surfactant via a hydrothermal route at low temperature through different synthesis procedures. Rodlike GaOOH crystals with average length of ∼2.5 μm and width of 1.5 μm were prepared when the initial molar ratio of Ga to OH was 1:3. β-Ga2O3 materials were derived from GaOOH by calcination at 900 °C, and the initial morphology was retained. γ-Ga2O3 nanotubes up to 65 nm in length, with internal and external diameters of around 0.8 and 3 nm, were achieved directly in solution with and without surfactant under hydrothermal treatment condition at 100 °C when the initial molar ratio of Ga to OH was 1:5. The combination of X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, small area electron diffraction (SAED), and energy dispersive X-ray analysis (EDX) were employed to characterize the resulting nano- to microsized structures. Cationic and nonionic surfactants were used in this study. Detailed results are presented.
Spin Wave Wells in Nonellipsoidal Micrometer Size Magnetic Elements (2002)

We show experimentally and by model calculations that in finite, nonellipsoidal, micrometer size magnetic thin film elements the dynamic magnetic eigenexcitations (spin waves) may exhibit strong spatial localization. This localization is due to the formation of a potential well for spin waves in the highly inhomogeneous internal magnetic field within the element.
Dose to water versus dose to medium in proton beam therapy (2009)

Dose in radiation therapy is traditionally reported as the water-equivalent dose, or dose to water. Monte Carlo dose calculations report dose to medium and thus a methodology is needed to convert dose to medium into dose to water (or vice versa) for comparison of Monte Carlo results with results from planning systems. This paper describes the development of a formalism to convert dose to medium into dose to water for proton fields when simulating the dose with Monte Carlo techniques. The conversion is based on relative stopping power but also considers energy transferred via nuclear interactions. The influence of different interaction mechanisms of proton beams (electromagnetic versus nuclear) is demonstrated. Further, an approximate method for converting doses retroactively is presented. Based on the outlined formalism, five proton therapy patients with a total of 33 fields were analyzed. Dose distributions, dose volume histograms and absolute doses to assess the clinical significance of differences between dose to medium and dose to water are presented. We found that the difference between the two dose reporting definitions can be up to 10% for high CT numbers if analyzing the mean dose to the target. The difference is clinically insignificant for soft tissues. For the structures analyzed, the mean dose to water could be converted to dose to medium by applying a correction factor increasing linearly with increasing average CT number in the volume. We determined that an approximate conversion method, done retroactively with an energy-independent stopping power ratio and without considering nuclear interaction events separately (as compared to on-the-fly conversion during simulation), is sufficiently accurate to compute mean doses. It is insufficient, however, when analyzing the beam range. For proton beams stopping in bony anatomy, the predicted beam range can differ by 2-3 mm when comparing dose to tissue and dose to water.
Interactive Teachable Cognitive Agents: Smart Building Blocks for Multiagent Systems (2016)

Developing a complex intelligent system by abstracting their behaviors, functionalities, and reasoning mechanisms can be tedious and time consuming. In this paper, we present a framework for developing an application or software system based on smart autonomous components that collaborate with the developer or user to realize the entire system. Inspired by teachable approaches and programming-by-demonstration methods in robotics and end-user development, we treat intelligent agents as teachable components that make up the system to be built. Each agent serves different functionalities and may have prebuilt operations to accomplish its own design objectives. However, each agent may also be equipped with in-built social-cognitive traits to interact with the user or other agents in order to adapt its own operations, objectives, and relationships with others. The results of adaptation can be in the form of groups or multiagent systems as new aggregated components. This approach is made to tackle the difficulties in completely programming the entire system by allowing the user to teach the components toward the desired behaviors in the situated context of the application. We exemplify this novel method with cases in the domains of human-like agents in virtual environment and agents for in-house caregiving.
Quantitatively Interpreted Enhanced Inhibition of Cytochrome P450s by Heteroaromatic Rings Containing Nitrogen (2011)

It has been known for a long time that certain substructures bind to the heme iron in cytochromes P450. Detection of spectroscopic changes and crystal structures of protein ligand complexes have provided qualitative evidence, including for aromatic nitrogen-containing ligands. Compounds containing these same substructures are more likely to inhibit cytochrome P450s than expected due to lipophilicity. These two sets of observations are not easily linked by experiment, because binding to the iron atom alone is not readily measured. Quantum mechanical (density functional) calculations of binding energies for a number of different aromatic heterocycles to heme iron in a range of oxidation and spin states can provide a quantitative link between the observed structures and the biochemical inhibition that is measured. The studies reported here for a set of heteroaromatic rings containing nitrogen begin with quantum mechanical calculations which provide geometries and binding energies. Subsequently, AstraZeneca's database of cytochrome P450 inhibition assays has been searched to find data that are relevant to the same set of heteroaromatic compounds. These data have been analyzed in a number of fashions to account for both the narrow dynamic range of the assays and the lipophilicity dependence of this kind of inhibition. Finally, crystal structures have provided experimental geometric information. Taken together these different sources suggest that binding to the metal in our inhibition assays is dominated by Fe(III) in its doublet state, most likely occurring when the iron is pentavalent. Computed binding energies to this state contrast with the hydrogen-bond acceptor ability and basicity of the compounds, neither of which are able to correctly account for the effect of the particular environment in which the iron is found. This highlights the value of modeling biochemical events as closely as can be computationally afforded. The computational protocol devised was used to make predictions about a set of as yet unknown heteroaromatic compounds suggested by Pitt et al.
Toward a More Accurate Quantitation of the Activity of Recombinant Retroviruses: Alternatives to Titer and Multiplicity of Infection (2000)

In this paper, we present a mathematical model with experimental support of how several key parameters govern the adsorption of active retrovirus particles onto the surface of adherent cells. These parameters, including time of adsorption, volume of virus, and the number, size, and type of target cells, as well as the intrinsic properties of the virus, diffusion coefficient, and half-life (t(1/2)), have been incorporated into a mathematical expression that describes the rate at which active virus particles adsorb to the cell surface. From this expression, we have obtained estimates of C(vo), the starting concentration of active retrovirus particles. In contrast to titer, C(vo) is independent of the specific conditions of the assay. The relatively slow diffusion (D = 2 x 10(-8) cm(2)/s) and rapid decay (t(1/2) = 6 to 7 h) of retrovirus particles explain why C(vo) values are significantly higher than titer values. Values of C(vo) also indicate that the number of defective particles in a retrovirus stock is much lower than previously thought, which has implications especially for the use of retroviruses for in vivo gene therapy. With this expression, we have also computed AVC (active viruses/cell), the number of active retrovirus particles that would adsorb per cell during a given adsorption time. In contrast to multiplicity of infection, which is based on titer and is subject to the same inaccuracies, AVC is based on the physicochemical parameters of the transduction assay and so is a more reliable alternative.
One-dimensional ballistic resistor in hot-electron regime: nonlinear and negative differential resistance to 10 THz (1989)

We extend into the high field regime the usual (very low field) treatment of the one-dimensional (ID) ballistic resistor that leads to quantised resistance. We find nonlinear resistance and eventually negative differential resistance (NDR) with a high-frequency cutoff above 10 THz. We outline preliminary experimental evidence in support.
Regulation of T‐cell responses by PTEN (2008)

The phosphoinositide 3-kinase (PI3K) signaling pathway plays a critical role in the development, activation, and homeostasis of T cells by modulating the expression of survival and mitogenic factors in response to a variety of stimuli. Ligation of the antigen receptor, costimulatory molecules, and cytokine receptors activate PI3K, resulting in the production of the lipid second messenger phosphatidylinositol-3,4,5-triphosphate (PIP(3)). A number of molecules help to regulate the activity of this pathway, including the lipid phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome 10). By limiting the amount of PIP(3) available within the cell, PTEN directly opposes PI3K activity and influences the selection of developing thymocytes as well as the activation requirements of mature T cells. T cells with unchecked PI3K activity, as a result of PTEN deficiency, contribute to the development of both autoimmune disease and lymphoma. This review dissects our current understanding of PI3K and PTEN and discusses why appropriate balance of these molecules is necessary to maintain normal T-cell responses.
SPECIFIC RESPONSES OF BACTERIAL CELLS TO DIOXINS (2003)

Five different recombinant bioluminescent strains of Escherichia coli that contain the recA (responsive to DNA damage related stress), fabA (membrane damage), katG (oxidative damage), grpE (protein damage), and lac (constitutive expression, general toxicity) promoters fused to the bacterial lux operon from either Vibrio fischeri or Photorhabdus luminescens were used to describe the different mechanisms of toxicity that several dibenzo-p-dioxins and dibenzofurans have on bacteria, as well as to determine whether bacteria can sensitively detect the presence of these compounds. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) was found to cause only DNA-related damage to bacterial cells. However, the four stress-responsive strains showed positive responses after addition of l,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD), whereas 2,3,7,8-tetrachlorodibenzo-p-furan (2,3,7,8-TCDF) caused only DNA, oxidative, and protein damage. However, 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) was not found to induce any stresses tested for in this study, that is, DNA, membrane, oxidative, and protein damage, indicating that each congener might differentially interact with the cell, stimulating differential stress responses within them. By using the constitutive strain, we found that the level of cellular toxicity experienced due to the addition of these four dioxins decreased in the order of 2,3,7,8-TCDD (the most toxic), 1,2,3,4-TCDD, 2,8-DCDD, and 2,3,7,8-TCDF. The 20% effective concentration (EC20), defined in this study the concentration of chemical that causes a 20% decrease in the bioluminescence 60 min after induction, was only 0.1 μg/L for 2,3,7,8-TCDD, a value that is lower than that of the other congeners and demonstrates that 2,3,7,8-TCDD was the most toxic compound tested in this study.
Application of Chicory as Corrosion Inhibitor for Acidic Environments (2013)

Summary During acidizing stimulation or cleanup operations, metal tubulars, downhole tools/valves, and surface lines are exposed to acidic fluids and are prone to corrosion. Because corrosion rates drastically increase in high-temperature wells, controlling corrosion is critical and must be dealt with carefully. In addition, corrosion protection is important for maintaining the integrity and long life of downhole tools installed in a well. Several corrosion inhibitors, such as quaternary ammonium compounds and propargyl alcohol-based compounds, have been effectively used in the industry. However, because of stringent environmental regulations, attention has focused on the development of new corrosion inhibitors that are environmentally benign. Food-grade products that are considered "green" chemicals have significant potential as corrosion inhibitors in the oil and gas industry. In this paper, application of chicory as a corrosion inhibitor for high-temperature and strong-acidic conditions is discussed. Chicory is a perennial bush plant available in many parts of the world. The root of the chicory plant can be roasted and ground for use as a coffee substitute or additive. Chicory is environmentally acceptable and, being of plant origin, is widely recognized as biodegradable in nature. This study shows that chicory can provide corrosion protection for alloys such as N-80, 13Cr-L80, and 1010 steel in the presence of either inorganic or organic acids at temperatures up to 250°F (121°C). Considering its performance and lack of toxicity issues, chicory has significant potential for acid corrosion-inhibition applications. The mixing procedure for preparing the blend, experimental setup and test procedure, and laboratory results of high-pressure/high-temperature (HP/HT) corrosion tests are discussed.
Modes of Spectating (2009)

Modes of Spectating investigates the questions posed by new artistic and technological mediums on the viewer experience. These new visual tools influence not only how spectators view, but also how what they view determines what artists create. Alison Oddey and Christine White analyze how gaming and televisual media and entertainment are used by young people, and the resulting psychological challenges of understanding how viewers navigate these virtual worlds and surroundings. This multidisciplinary approach brings together ideas and examples from gaming art, photography, sculpture, and performance; it will be a valuable text for scholars of both media and art.
A multibitrate optical burst-mode packet receiver (2002)

We have developed an advanced multi bit rate optical burst-mode packet receiver. This receiver can handle four multiplexed bit rate NRZ signals independently of bit rate order and number. It will encourage the penetration of fibre to the home.
A Fascinating Journey (2008)

The changes that have come about in the practice of law in over the past 75 years are discussed. Modern technology has ensured that the legal system become more effective and efficient in serving its clients.
TNF Receptor Type 2 (p75) Functions as a Costimulator for Antigen-Driven T Cell Responses In Vivo (2006)

Naive T cells require costimulation for robust Ag-driven differentiation and survival. Members of the TNFR family have been shown to provide costimulatory signals conferring survival at distinct phases of the T cell response. In this study, we show that CD4 and CD8 T cells depend on TNFR type 2 (p75) for survival during clonal expansion, allowing larger accumulation of effector cells and conferring protection from apoptosis for a robust memory pool in vivo. We demonstrate using the MHC class I-restricted 2C TCR and MHC class II-restricted AND TCR transgenic systems that TNFR2 regulates the threshold for clonal expansion of CD4 and CD8 T cell subsets in response to cognate Ag. Using a novel recombinant Listeria monocytogenes (rLM) expressing a secreted form of the 2C agonist peptide (SIY) to investigate the role of TNFR2 for T cell immunity in vivo, we found that TNFR2 controls the survival and accumulation of effector cells during the primary response. TNFR2-/- CD8 T cells exhibit loss of protection from apoptosis that is correlated with diminished survivin and Bcl-2 expression. Null mutant mice were more susceptible to rLM-SIY challenge at high doses of primary infection, correlating with impaired LM-specific T cell response in the absence of TNFR2-mediated costimulation. Moreover, the resulting memory pools specific for SIY and listeriolysin O epitopes derived from rLM-SIY were diminished in TNFR2-/- mice. Thus, examination of Ag-driven T cell responses revealed a hitherto unknown costimulatory function for TNFR2 in regulating T cell survival during the differentiation program elicited by intracellular pathogen in vivo.
Evidence that the SKI antiviral system of Saccharomyces cerevisiae acts by blocking expression of viral mRNA. (1993)

The SKI2 gene is part of a host system that represses the copy number of the L-A double-stranded RNA (dsRNA) virus and its satellites M and X dsRNA, of the L-BC dsRNA virus, and of the single-stranded replicon 20S RNA. We show that SKI2 encodes a 145-kDa protein with motifs characteristic of helicases and nucleolar proteins and is essential only in cells carrying M dsRNA. Unexpectedly, Ski2p does not repress M1 dsRNA copy number when M1 is supported by aN L-A cDNA clone; nonetheless, it did lower the levels of M1 dsRNA-encoded toxin produced. Since toxin secretion from cDNA clones of M1 is unaffected by Ski2p, these data suggest that Ski2p acts by specifically blocking translation of viral mRNAs, perhaps recognizing the absence of cap or poly(A). In support of this idea, we find that Ski2p represses production of beta-galactosidase from RNA polymerase I [no cap and no poly(A)] transcripts but not from RNA polymerase II (capped) transcripts.
Color transformation methods for dichromats (2010)

Color blindness is a serious perception problem. Suffering individuals cannot understand messages, which are carrying by many images, especially those, distributed by WWW. In this paper we are proposing three image processing methods to enhance image recognition and understanding by persons with dichromacy. Color difference image is introduced to represent color perception dissimilarity. Two color transformation methods are presented. Results of tests proved the usefulness of the methods for fast color transformation of images in the WWW environment.
Welding, Brazing, and Soldering (1993)

Volume 6 provides information on both the theory and practice of joining engineered materials and parts. It explains the underlying science of welding, brazing, and soldering, emphasizing how chemistry, physics, and metallurgy affect weldment properties and performance. The volume covers nearly 30 of the most common joining methods, describing process parameters, advantages and limitations, and equipment requirements. It also provides extensive information on specific materials, including selection criteria, application considerations, joining properties, and related data. Other topics covered include welding in special environments, corrosion, process modeling, evaluation, and quality control. For information on the print version of Volume 6, ISBN: 978-0-87170-382-8, follow this link.
Record High Electron Mobility of 6.3 cm<sup>2</sup>V<sup>−1</sup>s<sup>−1</sup> Achieved for Polymer Semiconductors Using a New Building Block (2014)

A new electron acceptor building block, 3,6-di(pyridin-2-yl)pyrrolo[3,4-c ]pyrrole-1,4(2H ,5H)-dione (DBPy), is used to construct a donor-acceptor polymer, PDBPyBT. This polymer exhibits a strong self-assembly capability, to form highly crystalline and oriented thin films with a short π-π stacking distance of 0.36 nm. PDBPyBT shows ambipolar charge-transport performance in organic thin-film transistors, reaching a record high electron-mobility value of 6.30 cm(2) V(-1) s(-1).