gebhart/patrepeval huggingface dataset:
Iron-control additives improve acidizing (1989)

Iron sulfide and sulfur precipitation in sour wells can be controlled with iron-sequestering agents and sulfide modifiers. Oil production has been routinely increased in sour wells where precipitation of iron sulfide and elemental sulfur has been brought under control. Production increases have been especially noteworthy on wells that had a history of rapid production decline after acid stimulation. Twenty-fold production increases have been recorded. Key to the production increase has been to increase permeability with: Iron chelating agents that control precipitation of iron sulfide. A sulfide modifier that reduces precipitation of solids in the presence of excessive amounts of hydrogen sulfide and prevents precipitation of elemental sulfur.
Straight β-SiC nanorods synthesized by using C–Si–SiO2 (2000)

Straight beta-silicon carbide nanorods have been grown on silicon wafers using hot filament chemical vapor deposition with iron particles as catalyst. A plate made of a C–Si–SiO2 powder mixture was used as carbon and silicon sources. Hydrogen, which was the only gas fed into the deposition system, acts both as a reactant and as a mass transporting medium. The diameter of the β-SiC nanorod ranged from 20 to 70 nm, while its length was approximately 1 μm. A growth mechanism of beta-silicon carbide nanorods was proposed. The field emission properties of the beta-silicon carbide nanorods grown on the silicon substrate are also reported.
Both Subunits of ADP-Glucose Pyrophosphorylase Are Regulatory (2004)

The allosteric enzyme ADP-Glc pyrophosphorylase (AGPase) catalyzes the synthesis of ADP-Glc, a rate-limiting step in starch synthesis. Plant AGPases are heterotetramers, most of which are activated by 3-phosphoglyceric acid (3-PGA) and inhibited by phosphate. The objectives of these studies were to test a hypothesis concerning the relative roles of the two subunits and to identify regions in the subunits important in allosteric regulation. We exploited an Escherichia coli expression system and mosaic AGPases composed of potato (Solanum tuberosum) tuber and maize (Zea mays) endosperm subunit fragments to pursue this objective. Whereas potato and maize subunits have long been separated by speciation and evolution, they are sufficiently similar to form active mosaic enzymes. Potato tuber and maize endosperm AGPases exhibit radically different allosteric properties. Hence, comparing the kinetic properties of the mosaics to those of the maize endosperm and potato tuber AGPases has enabled us to identify regions important in regulation. The data herein conclusively show that both subunits are involved in the allosteric regulation of AGPase. Alterations in the small subunit condition drastically different allosteric properties. In addition, extent of 3-PGA activation and extent of 3-PGA affinity were found to be separate entities, mapping to different regions in both subunits.
The role of rotaviruses in pediatric diarrhea (1986)

FLORES, JORGE MD; NAKAGOMI, OSAMU MD PHD; NAKAGOMI, TOYOKO MD, PHD; GLASS, ROGER MD, PHD; GORZIGLIA, MARIO PHD; ASKAA, JON PHD; HOSHINO, YASUTAKA PHD; PEREZ-SCHAEL, IRENE MSC; KAPIKIAN, ALBERT Z. MD Author Information
Quantum dot semiconductor optical amplifier/silicon external cavity laser for O-band high-speed optical communications (2015)

We report a hybrid integrated external cavity laser by butt coupling a quantum dot reflective semiconductor optical amplifier and a silicon-on-insulator chip. The device lasers at 1302 nm in the O-band, a wavelength regime critical to data communication systems. We measured 18 mW on-chip output power and over 50-dB side-mode suppression ratio. We also demonstrated open eye diagrams at 10 and 40 Gb/s.
Secure wireless Internet access in public places (2002)

We have built a network, called the CHOICE network, which globally authenticates users and then securely connects them to the Internet via a high-speed local area wireless network. Our network provides easy-to-use, individual-centric, service-oriented wireless Internet access in places other than the traditional corporate offices and homes. Our architecture is hardware and protocol agnostic and is built on an easily deployable software module called the protocol for authorization and negotiation of services or PANS. PANS provides authorization, access, privacy, security, policy enforcement, quality of service (QoS) and accounting. In this paper, we describe PANS in detail. We discuss our system design and operation, implementation and performance. We evaluate PANS and show that it is scalable and secure. Our network has been deployed and is operational at a local mall in Bellevue, Washington.
Upconversion pumped green lasing in erbium doped fluorozirconate fibre (1991)

The first demonstration of upconversion pumped lasing at green wavelengths in an Er3+-doped fluorozirconate fibre laser is reported. 15 mW continuous wave emission at a wavelength of 546 nm has been achieved for an absorbed pump power of 300 mW.
The role of hafnium in supported titanium/hafnium catalysts for olefin polymerization (1989)

Several MgCl2-supported catalysts containing different amounts of titanium and hafnium were prepared. These systems are active for the polymerization of ethylene and α-olefins as well as for their copolymerization, giving much broader molecular weight distributions as compared with similar systems containing titanium only. Polymer properties, such as melt flow index and shear sensitivity can be varied by catalyst composition and addition of a Lewis base (ethyl benzoate). Gel permeation chromatography curves obtained in a single reactor (one-stage process) are comparable to those obtained in two reactors (two-stage process). An analysis of comparative kinetics for various conditions and the corresponding polymer properties suggests that Hf-containing sites produce much longer chains than do Ti-containing sites; at the same time Hf-containing sites display lower activity and higher tendency to interact with ethyl benzoate. Similar investigations with model catalysts are described to support these hypotheses.
New biosynthetic anthracyclines related to barminomycins incorporating barbiturates in their moiety. (1990)

Three new anthracyclines, FCE 21424 (2), FCE 24366 (3) and FCE 24367 (4), were isolated from culture broths of Streptomyces peucetius and its mutant strains after addition of sodium barbiturates during the fermentation. Structural assignment, achieved through spectroscopic and degradative studies, that the new anthracyclines had a common barminomycin-like structure incorporating different barbiturate moieties. The new anthracyclines were found to display outstanding cytotoxicity and remarkable potency "in vivo" against P388 ascitic leukemia.
<title>Phase signature-based image authentication watermark robust to compression and coding</title> (2004)

We present the further development of a watermarking technique that embeds an authentication signal in an image. In this paper, we concentrate on the JPEG 2000 image format. The detection/extraction of this signal can then be used to decide whether the image has gone through any intentional malicious tampering. Therefore, the watermark needs to be fragile to such tampering attacks. On the other hand, we need to make sure that the authentication is robust to change resulting from the watermarking process itself, or from necessary changes such as image compression. We address the robustness against watermarking process issue in two ways. First, we decompose the image into phase and magnitude values. A signature is then generated from the phase values. In particular, binary phase-only filters and their variants will are utilized for this. This signature is subsequently hidden into the magnitude part by a bit-plane embedding technique. The disjoint operations of signature generation and signature embedding minimize the embedding artifacts of the authentication signal. Secondly, we use wavelet decomposition, whereby, the signature can be generated from one subband, and then it can be embedded in other subband(s), or the same subband.
Solution Structure and Structural Dynamics of Envelope Protein Domain III of Mosquito- and Tick-Borne Flaviviruses (2004)

The mosquito-borne West Nile (WNV) and dengue 2 (DEN2V) viruses and tick-borne Langat (LGTV) and Omsk hemorrhagic fever (OHFV) viruses are arthropod-borne flaviviruses (family Flaviviridae, genus Flavivirus). These viruses are quite similar at both the nucleotide and amino acid level, yet they are very divergent in their biological properties and in the diseases they cause. The objective of this study was to examine the putative receptor-binding domains of the flaviviruses, the envelope (E) protein domain III (D3), which assume very similar structures either as part of the whole envelope protein or as individual entities, and to define the biophysical properties that distinguish among these viruses. Circular dichroism and Fourier transform infrared spectroscopy were employed to monitor the solution structure of these proteins. While the spectroscopic results found that the D3 from each of these viruses is composed of either beta-sheets or beta-turns, which is consistent with X-ray crystal data for tick-borne encephalitis and dengue viruses, these results reveal that recombinant D3s (rED3s) derived from tick-borne flaviviruses (LGT-rED3 and OHF-rED3) were similar to each other, while those from mosquito-borne flaviviruses (WN-rED3 and DEN-rED3) were similar to each other yet distinct from rED3 of the tick-borne viruses. Protein dynamic studies probed by fluorescence quenching and hydrogen/deuterium exchange found that the rED3s are dynamic entities. The tick-borne proteins again exhibit very similar dynamic properties, which are different from the mosquito-borne proteins. The WN-rED3 is significantly less stable than the other three rED3s. Overall, these differences in biophysical properties correlate with biological properties of these viruses that tick-borne flaviviruses are more stable than mosquito-borne flaviviruses.
Modeling of the ultrasonic/sonic driller/corer: USDC (2002)

Future NASA missions to Mars require sampling techniques for in-situ analysis and/or sample return to Earth. One of the major limitations of sample collection on Mars and other low gravity environments using conventional drilling is the need for high axial force during drilling. In order to address this problem an ultrasonic/sonic drilling/coring (USDC) mechanism based on an ultrasonic horn driven by a piezoelectric stack has been developed. The horn drives a free mass, which resonates, between the horn and drill stem. Tests have shown that this device addresses some of the key challenges to this NASA objective of planetary in-situ analysis or sampling. The USDC is lightweight (450 g), requires low preload (<5 N) and can be driven at low power (5 W). The device has been shown to drill various rocks including granite, diorite, basalt and limestone. Although the drill is driven electrically at 20 kHz, a substantial sub-harmonic acoustic component is found that is crucial to drilling performance. Models that explain this low frequency coupling in the horn, free mass, drill stem and rock will be presented.
GII.4 Norovirus Protease Shows pH-Sensitive Proteolysis with a Unique Arg-His Pairing in the Catalytic Site (2019)

Human noroviruses (NoVs) are the main cause of epidemic and sporadic gastroenteritis. Phylogenetically, noroviruses are divided into seven genogroups, with each divided into multiple genotypes. NoVs belonging to genogroup II and genotype 4 (GII.4) are globally most prevalent. Genetic diversity among the NoVs and the periodic emergence of novel strains present a challenge for the development of vaccines and antivirals to treat NoV infection. NoV protease is essential for viral replication and is an attractive target for the development of antivirals. The available structure of GI.1 protease provided a basis for the design of inhibitors targeting the active site of the protease. These inhibitors, although potent against the GI proteases, poorly inhibit the GII proteases, for which structural information is lacking. To elucidate the structural basis for this difference in the inhibitor efficiency, we determined the crystal structure of a GII.4 protease. The structure revealed significant changes in the S2 substrate-binding pocket, making it noticeably smaller, and in the active site, with the catalytic triad residues showing conformational changes. Furthermore, a conserved arginine is found inserted into the active site, interacting with the catalytic histidine and restricting substrate/inhibitor access to the S2 pocket. This interaction alters the relationships between the catalytic residues and may allow for a pH-dependent regulation of protease activity. The changes we observed in the GII.4 protease structure may explain the reduced potency of the GI-specific inhibitors against the GII protease and therefore must be taken into account when designing broadly cross-reactive antivirals against NoVs.<b>IMPORTANCE</b> Human noroviruses (NoVs) cause sporadic and epidemic gastroenteritis worldwide. They are divided into seven genogroups (GI to GVII), with each genogroup further divided into several genotypes. Human NoVs belonging to genogroup II and genotype 4 (GII.4) are the most prevalent. Currently, there are no vaccines or antiviral drugs available for NoV infection. The protease encoded by NoV is considered a valuable target because of its essential role in replication. NoV protease structures have only been determined for the GI genogroup. We show here that the structure of the GII.4 protease exhibits several significant changes from GI proteases, including a unique pairing of an arginine with the catalytic histidine that makes the proteolytic activity of GII.4 protease pH sensitive. A comparative analysis of NoV protease structures may provide a rational framework for structure-based drug design of broadly cross-reactive inhibitors targeting NoVs.
Adaptive language modeling using the maximum entropy principle (1993)

We describe our ongoing efforts at adaptive statistical language modeling. Central to our approach is the Maximum Entropy (ME) Principle, allowing us to combine evidence from multiple sources, such as long-distance triggers and conventional short.distance trigrams. Given consistent statistical evidence, a unique ME solution is guaranteed to exist, and an iterative algorithm exists which is guaranteed to converge to it. Among the advantages of this approach are its simplicity, its generality, and its incremental nature. Among its disadvantages are its computational requirements. We describe a succession of ME models, culminating in our current Maximum Likelihood / Maximum Entropy (ML/ME) model. Preliminary results with the latter show a 27% perplexity reduction as compared to a conventional trigram model.
Remote query pressure measurement using magnetoelastic sensors (1999)

Two magnetostriction-based methods for measuring atmospheric pressure are presented. Each technique correlates changes in pressure with the characteristic resonant frequency of a magnetoelastic magnetostrictive thick-film sensor. In each case the sensor is monitored remotely, using an adjacently located pickup coil, without the use of physical connections to the sensor.
A vitamin B12 conjugate of exendin‐4 improves glucose tolerance without associated nausea or hypophagia in rodents (2018)

These novel findings highlight the potential clinical utility of B12-Ex4 conjugates as possible future T2DM therapeutics with reduced incidence of adverse effects.
H<sub>2</sub>S Adsorption/Oxidation on Adsorbents Obtained from Pyrolysis of Sewage-Sludge-Derived Fertilizer Using Zinc Chloride Activation (2001)

Sewage-sludge-derived fertilizer, Terrene, was used as a precursor of adsorbents tested for removal of hydrogen sulfide from moist air. The adsorbents were obtained by pyrolysis of zinc chloride-impregnated granular fertilizer at 400, 600, 800, and 950 °C in a nitrogen atmosphere. Subsamples of the materials obtained were washed with hydrochloric acid to remove the excess zinc chloride and other soluble chlorides. This treatment results in a significant increase in the sample porosity. The highest H2S removal capacity was obtained for the sample carbonized at 600 °C. This results from release of zinc chloride vapor during heat treatment, which acts to form micropores in the carbonaceous deposit. When inorganic oxides and salts are present in sufficient quantities, hydrogen sulfide undergoes surface reactions and is left on the surface in the form of nonvolatile sulfides and sulfates. The pores are gradually filled as the surface reaction proceeds. If catalytic metal oxides are removed, hydrogen sulfide is oxidized predominantly to sulfuric acid through the catalytic effect of the adsorption sites in the small micropores of the carbonaceous deposit. The removal of H2S occurs until all pore entrances are blocked with the oxidation product.
Direct diode lasers and their advantages for materials processing and other applications (2015)

The brightness of diode lasers is improving continuously and has recently started to approach the level of some solid state lasers. The main technology drivers over the last decade were improvements of the diode laser output power and divergence, enhanced optical stacking techniques and system design, and most recently dense spectral combining. Power densities at the work piece exceed 1 MW/cm<sup>2</sup> with commercially available industrial focus optics. These power densities are sufficient for cutting and welding as well as ablation. Single emitter based diode laser systems further offer the advantage of fast current modulation due their lower drive current compared to diode bars. Direct diode lasers may not be able to compete with other technologies as fiber or CO<sub>2</sub>-lasers in terms of maximum power or beam quality. But diode lasers offer a range of features that are not possible to implement in a classical laser. We present an overview of those features that will make the direct diode laser a very valuable addition in the near future, especially for the materials processing market. As the brightness of diode lasers is constantly improving, BPP of less than 5mm*mrad have been reported with multikW output power. Especially single emitter-based diode lasers further offer the advantage of very fast current modulation due to their low drive current and therefore low drive voltage. State of the art diode drivers are already demonstrated with pulse durations of <10μs and repetition rates can be adjusted continuously from several kHz up to cw mode while addressing power levels from 0-100%. By combining trigger signals with analog modulations nearly any kind of pulse form can be realized. Diode lasers also offer a wide, adaptable range of wavelengths, and wavelength stabilization. We report a line width of less than 0.1nm while the wavelength stability is in the range of MHz which is comparable to solid state lasers. In terms of applications, especially our (broad) wavelength combining technology for power scaling opens the window to new processes of cutting or welding and process control. Fast power modulation through direct current control allows pulses of several microseconds with hundreds of watts average power. Spot sizes of less than 100 μm are obtained at the work piece. Such a diode system allows materials processing with a pulse parameter range that is hardly addressed by any other laser system. High productivity material ablation with cost effective lasers is enabled. The wide variety of wavelengths, high brightness, fast power modulation and high efficiency of diode lasers results in a strong pull of existing markets, but also spurs the development of a wide variety of new applications.
Design, synthesis, and characterization of a model peptide having potent calcitonin-like biological activity: implications for calcitonin structure/activity (1985)

A calcitonin analogue, MCT-II, having the potential to form an amphiphilic alpha-helix from residue 8 to residue 22 with a continuous surface of aliphatic leucine side chains on the hydrophobic face of the helix has been synthesized, and its physical and biological properties have been characterized. Properties exhibited by this peptide, including self-association in the micromolar concentration range with a concomitant increase in the percentage of alpha-helical structure, formation of stable monolayers at the air-water interface, and adsorption to the surface of egg lecithin single-bilayer vesicles, demonstrate that MCT-II can readily form an amphiphilic alpha-helical structure. Though MCT-II has minimal sequence homology to any particular natural analogue from residue 8 to residue 22, it has biological activity similar to that of salmon calcitonin I for receptor binding in brain and kidney membranes, for activation of adenylate cyclase, and in hypocalcemic potency in vivo. The amphiphilic alpha-helical structure of MCT-II, therefore, is important for binding to calcitonin receptors. It is also apparent that a hydrophilic residue commonly occurring on the hydrophobic face (position 15) in the natural calcitonins is not required for high biological activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Adaptive Immunity Restricts Replication of Novel Murine Astroviruses (2012)

The mechanisms of astrovirus pathogenesis are largely unknown, in part due to a lack of a small-animal model of disease. Using shotgun sequencing and a custom analysis pipeline, we identified two novel astroviruses capable of infecting research mice, murine astrovirus (MuAstV) STL1 and STL2. Subsequent analysis revealed the presence of at least two additional viruses (MuAstV STL3 and STL4), suggestive of a diverse population of murine astroviruses in research mice. Complete genomic characterization and subsequent phylogenetic analysis showed that MuAstV STL1 to STL4 are members of the mamastrovirus genus and are likely members of a new mamastrovirus genogroup. Using Rag1(-/-) mice deficient in B and T cells, we demonstrate that adaptive immunity is required to control MuAstV infection. Furthermore, using Stat1(-/-) mice deficient in innate signaling, we demonstrate a role for the innate immune response in the control of MuAstV replication. Our results demonstrate that MuAstV STL permits the study of the mechanisms of astrovirus infection and host-pathogen interactions in a genetically manipulable small-animal model. Finally, we detected MuAstV in commercially available mice, suggesting that these viruses may be present in academic and commercial research mouse facilities, with possible implications for interpretation of data generated in current mouse models of disease.