gebhart/patrepeval huggingface dataset:
Thermal Cycling Response of Quasi-Isotropic Metal Matrix Composites (1992)

In this study, thermal cycling response of quasi-isotropic metal-matrix composite (MMC) with a stacking sequence of [0/ ± 45/90]s was investigated. The thermal cycles were imposed between temperatures of 316–649° C. Metallography of the samples at the edge has shown the presence of fiber-matrix debonding and ply-to-ply separation (delamination) in the 45 and 90 deg plies. The propensity for debonding was found to be greater when fibers are too close in any of these plies. Both closed form elastic analysis and linear finite element analysis using temperature dependent material properties were undertaken to evaluate the criticality of local stresses and strains in the constituent materials. Inelastic deformation around fiber-matrix interface leading to cracking in the 90 deg ply was best simulated by higher local variation in fiber volume fraction in the composite and the presence of initial process induced defect.
Challenges of Heavy Oil Fluid Sampling and Characterization (2012)

Abstract A significant portion of the world's hydrocarbon reserves is found in heavy oil reservoirs. Heavy oils are often found in shallow and highly unconsolidated reservoirs, or sometimes in deep, tight formations. Often the high asphaltic content of these oils results in relatively higher oil density and viscosity; hence, their lower reservoir mobility poses significant challenges to both sampling and PVT data measurements. Furthermore, modeling these fluids for reservoir evaluation requires special techniques to capture their unique phase behavior. The challenges of representative down-hole or surface fluid sample acquisition demand customized sampling methods to deal with: low oil mobility sand production from unconsolidated formations high asphaltene content and resulting high gradients formation of water-in-oil emulsion during co-production of water or gas lift operations or addition of diluents In addition, the prerequisite for laboratory measurement is special sample preparation to remove emulsified water. These high viscosity oils exhibit slower gas liberation below the bubble point and hence delayed gas-phase formation, thus making "true" oil property measurements a challenge. Difficulties associated with fluid modeling include characterizing apparent bubble point behavior, large viscosity changes with pressure and temperature, and asphaltene dropout. In this paper, we present a comprehensive methodology for heavy oil sampling and characterization in unconsolidated sands as well as in low permeability reservoirs. We present field examples to highlight the challenges and illustrate the methodology for fluid sampling, down-hole fluid analysis, laboratory PVT data acquisition, and modeling. Sampling methods for heavy and asphaltic oils were custom designed with special tools and sensors to obtain representative samples and precise down-hole fluid analysis data. New laboratory techniques were developed to prepare the samples for analysis and to distinguish between the "true" and "apparent" bubble point behavior exhibited by the heavy oil due to its non-equilibrium behavior. Fluid models based on a special equations of state (EoS) were employed for accurate description of heavy oil fluid phase behavior. In particular, we successfully applied the industry's first EoS for asphaltene gradients in heavy oil reservoirs that match down-hole fluid data.
Purification of a mammalian protein geranylgeranyltransferase. Formation and catalytic properties of an enzyme-geranylgeranyl pyrophosphate complex. (1993)

A protein geranylgeranyltransferase (PGGT) that transfers the geranylgeranyl group from geranylgeranyl pyrophosphate (GGPP) to the cysteine residue in the C-terminal sequence Cys-Ali-Ali-Leu (Ali is an aliphatic amino acid) of proteins and peptides has been purified to apparent homogeneity from bovine brain. This was accomplished by affinity chromatography of partially purified enzyme on a gel containing a covalently attached hexapeptide SSCILL. This peptide was identified as a tight-binding ligand of the PGGT by employing a semi-random peptide synthetic strategy. The purified enzyme consists of two subunits of apparent molecular mass 40 and 48 kDa. Affinity-purified PGGT effectively catalyzes the prenylation of peptides that contain a C-terminal Leu or Phe residue. The PGGT forms a stable binary complex with intact GGPP that can be isolated by gel filtration. Addition of a peptide substrate to this complex results in the quantitative transfer of the prenyl group to the peptide. This transfer occurs without the equilibration of enzyme-bound GGPP with free GGPP. When the PGGT was incubated with farnesyl pyrophosphate, the amount of binary complex formed was about 25% of that formed with GGPP.
Single-channel transmission in dispersion management links in conditions of very strong pulse broadening: application to 40 Gb/s signals on step-index fibers (1999)

The dynamic behavior of single-channel transmission on standard fibers with strong dispersion management has been theoretically and numerically analyzed. A single pulse and a pseudorandom pulse sequence have been compared in order to highlight the relevant role played by pulse interaction. A semianalytical theory of the bandwidth evolution demonstrates that the introduction of prechirp is very important for controlling the single pulse propagation and numerical results show that such a chirp also permits to limit the nonlinear pulse interaction when other pulses are present. Simulations of a 40 Gb/s return-to-zero (RZ) system operating in links encompassing step-index fibers, by adopting a periodical compensation of the chromatic dispersion have been performed and results show that a record distance of 1300 km can be achieved with an amplifier spacing of 100 km. A compensation of the fiber third order dispersion would extend the transmission to 1800 km, which corresponds to the limits imposed by the amplified spontaneous emission (ASE) noise of the optical amplifiers.
Neuroimaging of genesis and satiation of thirst and an interoceptor-driven theory of origins of primary consciousness (1999)

There are defined hypothalamic functions in the genesis of thirst, but little is known of the cortical processes subserving consciousness of thirst notwithstanding the medical disorders that occur in psychiatric illness, addiction, and the attested decline of thirst with aging. In 10 adult males, positron emission tomography scans were made (i) during genesis of moderate thirst by infusion of i.v. hypertonic saline 0.51 M, (ii) after irrigation of the mouth with water to remove the sensation of dryness, and (iii) 3, 14, 45, and 60 minutes after drinking water to fully satiate thirst. The correlation of regional cerebral blood flow with thirst score showed the major activation to be in the posterior cingulate. Maximum thirst sensation evoked 13 highly significant activations and 9 deactivations in cingulate and parahippocampal gyri, insula, thalamus, amygdala, and mesencephalon. It is possible that cingulate sites (Brodmann's areas 32, 24, and 31) that persisted with wet mouth but disappeared immediately after drinking to satiation may have an important role in the consciousness of thirst. Consciousness of thirst, a primal vegetative emotion, and satiation of thirst appear to be subserved by phylogenetically ancient brain regions. This is salient to current discussion on evolutionary emergence of primary consciousness.
Label Switched Path (LSP) Ping and Traceroute Reply Mode Simplification (2016)

The Multiprotocol Label Switching (MPLS) Label Switched Path (LSP) Ping and Traceroute use the Reply Mode field to signal the method to be used in the MPLS echo reply. This document updates the procedures for the "Reply via Specified Path" Reply Mode. The value of this Reply Mode is 5. The update creates a simple
Permeability of Rubbery and Glassy Membranes of Ionic Liquid Filled Polymersome Nanoreactors in Water (2015)

Nanoemulsion-like polymer vesicles (polymersomes) having ionic liquid interiors dispersed in water are attractive for nanoreactor applications. In a previous study, we demonstrated that small molecules could pass through rubbery polybutadiene membranes on a time scale of seconds, which is practical for chemical transformations. It is of interest to determine how sensitive the rate of transport is to temperature, particularly for membranes in the vicinity of the glass transition (Tg). In this work, the molecular exchange rate of 1-butylimidazole through glassy polystyrene (PS) bilayer membranes is investigated via pulsed field gradient nuclear magnetic resonance (PFG-NMR) over the temperature range from 25 to 70 °C. The vesicles were prepared by the cosolvent method in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][TFSI]), and four different polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock polymers with varying PS molecular weights were examined. The vesicles were transferred from the ionic liquid to water at room temperature to form nanoemulsion solutions of polymer vesicles in water. The exchange rate of 1-butylimidazole added to the aqueous solutions was observed under equilibrium conditions at each temperature. The exchange rate decreased as the membrane thickness increased, and the exchange rate through the glassy membranes was three to four times slower than through the rubbery polybutadiene membranes under the same experimental conditions. These results demonstrate that the permeability through nanosized membranes depends on both the dimension and chemistry of membrane-forming blocks. Furthermore, the exchange rate was investigated as a function of temperature in the vicinity of the Tg of PS-PEO membranes. The exchange rate, however, is not a strong function of the temperature in the vicinity of the membrane Tg, due to a combination of the nanoscopic dimension of the membrane, and some degree of solvent plasticization.
Substorm Cycle Dependence of Various Types of Aurora (2010)

[1] We combine 4861 identifications of substorm onsets from satellite global imagers (Polar UVI and IMAGE FUV) with DMSP particle data to investigate the substorm cycle dependence of the diffuse aurora (electrons and ions), monoenergetic aurora (produced by quasi-static electric fields), and broadband aurora (associated with Alfvenic acceleration). Although all types of aurora increase at substorm onset, broadband aurora shows a particular association with substorms and, especially, substorm onset. While diffuse electron and monoenergetic auroral precipitating power rises by 79% and 90%, respectively, following an onset, wave aurora rises by 182%. In the first 10–15 min following onset, the power associated with Alfvenic acceleration is comparable to monoenergetic acceleration (also called “inverted V” events). In general, this is not the case before onset, or indeed, during recovery. The rise time of the electron diffuse aurora following onset is much slower, about 50 min, and thus presumably extends into recovery. Discrete acceleration, which rises over just a few minutes, is already deep into decline, while diffuse auroral power is still rising. Most of the sharp increase in Alfvenic precipitating power at onset is associated with a 132% jump in the characteristic energy associated with broadband acceleration. Previous work has associated PiB signatures (which are compressional) in the magnetotail with dipolarization. More recently, FAST observations near the auroral zone have been used to show that there are nearly simultaneous sharp increases in Alfven waves, apparently created by mode coupling. The present work strongly supports the idea that the Alfvenic aurora has a particular connection to substorm onsets, with much of the auroral power over a substorm cycle concentrated shortly after onset. Finally, a superposed epoch analysis of commonly used coupling functions indicates a drop in the mean solar wind driving starting 20 min before substorm onset. However, the distribution of increases and decreases in solar wind driving is roughly symmetric about a peak at zero (no change) but with (rare) large drops in solar wind driving (“northward turnings”) outweighing large increases. Comparison with the distribution of random changes in solar wind driving leads us to suggest that probably only a minority of substorms are externally driven.
Information technologies and communication between parents and children (2001)

Se presenta una investigacion exploratoria que pretende, por una parte, conocer con mayor detalle como los chicos/as entre 12 y 16 anos utilizan distintas tecnologias audiovisuales, que sienten y piensan respecto de las actividades que desarrollan con las mismas y con quien les gusta hablar de dichas experiencias. Por otra, profundizar en algunas de las interacciones que se dan entre adultos y chicos/as, y especialmente entre padres e hijos, en referencia a las mismas tecnologias a partir de las actividades que con ellas realizan estos, en casa o en otros lugares. Se han analizado las respuestas dadas a sendos cuestionarios con diversos items comunes, administrados por separado a padres e hijos. Las respuestas dadas por estos ultimos reflejan un considerable nivel de insatisfaccion en las charlas que mantienen con distintos adultos respecto de las actividades mediaticas. Y se refuerza la tesis de que cada vez son mas los chicos/as que se socializan en las nuevas tecnologias de la informacion y la comunicacion con poco o ningun contraste de criterios adultos, configurando culturas infantiles propias. Las respuestas cruzadas de los progenitores y sus propios hijos/as nos muestran que aspectos relativos a la realidad mediatica estan sobreestimados o subestimados por los adultos en comparacion con los chicos/as, y cual es el grado de coincidencias y discrepancias en determinadas valoraciones que se observan entre generaciones. Los resultados pueden ser aplicables a la mejora de las relaciones entre adultos y adolescentes aprovechando la alta motivacion de estos ante el desarrollo de actividades con medios audiovisuales.
Identification and localization of a gene that specifies production of Escherichia coli DNA topoisomerase I. (1981)

A gene that specifies production of Escherichia coli DNA topoisomerase I (omega protein) was identified with the aid of a radioimmunoassay for this protein. E. coli DNA topoisomerase I was produced by Salmonella typhimurium merodiploids that harbored E. coli plasmid F' 123, but not by strains that lost this plasmid. Analysis of strains with spontaneous deletions of F' 123 showed that the gene, topA, required for production of the E. coli omega protein was between the trp operon and the cysB gene. Deletions that eliminated topA also eliminated the supX gene. We suggest that topA is the structural gene of E. coli DNA topoisomerase I and that topA is identical to supX.
Symmetry breaking and the turn-on fluorescence of small, highly strained carbon nanohoops (2019)

[<i>n</i>]Cycloparaphenylenes, or "carbon nanohoops," are unique conjugated macrocycles with radially oriented π-systems similar to those in carbon nanotubes. The centrosymmetric nature and conformational rigidity of these molecules lead to unusual size-dependent photophysical characteristics. To investigate these effects further and expand the family of possible structures, a new class of related carbon nanohoops with broken symmetry is disclosed. In these structures, referred to as <i>meta</i>[<i>n</i>]cycloparaphenylenes, a single carbon-carbon bond is shifted by one position in order to break the centrosymmetric nature of the parent [<i>n</i>]cycloparaphenylenes. Advantageously, the symmetry breaking leads to bright emission in the smaller nanohoops, which are typically non-fluorescent due to optical selection rules. Moreover, this simple structural manipulation retains one of the most unique features of the nanohoop structures-size dependent emissive properties with relatively large extinction coefficients and quantum yields. Inspired by earlier theoretical work by Tretiak and co-workers, this joint synthetic, photophysical, and theoretical study provides further design principles to manipulate the optical properties of this growing class of molecules with radially oriented π-systems.
ChemInform Abstract: N,N′-BIS(1-CHLOROALKYL)CARBODIIMIDES. II. REACTIONS WITH PROTON-CONTAINING NUCLEOPHILIC REAGENTS (1983)

Untersucht werden die Reaktionen der Carbodiimide (Ia) und (Ib) mit Nucleophilen - Wasser, Alkoholen, Phenolen, Aminen.
Role of maturation-promoting factor (p34cdc2-cyclin B) in differential expression of the Xenopus oocyte and somatic-type 5S RNA genes. (1994)

Transcription of 5S rRNA and tRNA genes by RNA polymerase III (pol III) in cytosolic extracts of unfertilized Xenopus eggs and in a reconstituted system derived from Xenopus oocytes is repressed by the action of one or more mitotic protein kinases. Repression is due to the phosphorylation of a component of the pol III transcription apparatus. We find that the maturation/mitosis-promoting factor kinase (MPF, p34cdc2-cyclin B) can directly mediate this repression in vitro. Affinity-purified MPF and immune complexes formed with antibodies to the protein subunits of MPF (p34cdc2 and cyclin B) retain both histone H1 kinase activity and the capacity to repress transcription in the reconstituted transcription system. Transcription complexes of oocyte-type 5S RNA genes and tRNA genes are quantitatively more sensitive to MPF repression than the corresponding transcription complexes of the somatic-type 5S RNA gene. The differential transcription of oocyte- and somatic-type genes observed during early Xenopus embryogenesis has been reproduced with the reconstituted transcription system and affinity-purified MPF. This differential transcription may be due to the instability of transcription complexes on the oocyte-type genes and the heightened sensitivity of soluble transcription factors to inactivation by mitotic phosphorylation. Our results suggest that MPF may play a role in vivo in the establishment of the embryonic pattern of pol III gene expression.
2-Amino-4,6-bis(4-chlorophenylthio)pyrimidine (2000)

The structure of the title compound, C 32 H 22 Cl 4 N 6 S 4 , (I), comprises two unique molecules that separately associate via a three-centre N—H...N/S interaction to form two linear one-dimensional hydrogen-bonded chains. The dihedral angles between the two phenyl rings and the pyrimidine ring for each molecule are 84.6 (1) and 87.8 (1)°, and 83.9 (1) and 80.1 (1)°.
Vapor vacuum extraction treatability study at the Idaho National Engineering Laboratory (1993)

During the 1960s and early 1970s, barreled mixed waste containing volatile organic compounds (VOCS) and radioactive waste was buried at the Subsurface Disposal Area (SDA) at the Idaho National Engineering Laboratory (INEL) Radioactive Waste Management Complex (RWMC). Over time, some of the barrels have deteriorated allowing, VOC vapors to be released into the vadose zone. The primary VOC contaminates of concern are CCl{sub 4} and trichloroethylene; however, chloroform, tetrachloroethylene, and 1,1,1-trichloroethane have also been detected. Vapor Vacuum Extraction (VVE) is one alternative being considered for remediation of the RWMC SDA vadose zone. A proposed pilot-scale treatability study (TS) will provide operation and maintenance costs for the design of the potential scale-up of the system.
Direct observations of synapses between L‐glutamate‐immunoreactive boutons and identified spinocervical tract neurones in the spinal cord of the cat (1992)

Four spinocervical tract cells in lumbosacral spinal cords of adult cats were physiologically characterized and intracellularly labelled with horseradish peroxidase. The neurones were examined with a light microscope and reconstructed. Selected regions were chosen for ultrastructural analysis. Thin sections were treated to reveal the presence of L-glutamate by using the postembedding immunogold method. Two antisera, which specifically recognise the presence of fixed glutamate in tissue, were used in the study. Somata, proximal, and distal dendrites of all four neurones received synaptic contacts from boutons which displayed an obvious immunogold reaction. These boutons formed between 35% and 48% of all synaptic contacts onto spinocervical tract cells. Glutamate-enriched boutons were associated with gold particle densities which were 2-3 times greater than the average densities associated with the surrounding neuropil. Their profiles had a mean diameter of 1.68 microns, contained round agranular synaptic vesicles, and formed asymmetrical synaptic junctions. However, not all boutons displaying these characteristics were enriched with glutamate. Immunogold studies of alternate thin sections, which were incubated with glutamate or GABA antiserum, demonstrated that synaptic boutons on spinocervical tract cells were either enriched with GABA or with glutamate and formed two separate populations which had distinct morphological characteristics. GABA-containing boutons contained irregularly shaped agranular vesicles and formed symmetrical synaptic junctions, whereas glutamate-enriched boutons corresponded to those described above. A further population of boutons, containing highly flattened vesicles, was not immunoreactive for GABA or glutamate. The evidence supports the idea that much of the excitatory transmission into the SCT is mediated by L-glutamate.
ChemInform Abstract: Remote Stereocontrol as a Synthetic Strategy: Diastereoselective Annulations on an Arene Tricarbonylchromium Template. (1998)

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.