gebhart/patrepeval huggingface dataset:
PI Factor, a Novel Type Quorum-sensing Inducer Elicits Pimaricin Production in Streptomyces natalensis (2004)

A chemically novel autoinducer (PI factor) has been purified from cultures of the pimaricin producer Streptomyces natalensis ATCC27448. The chemical structure of the PI molecule was identified as 2,3-diamino-2,3-bis (hydroxymethyl)-1,4-butanediol. Pimaricin biosynthesis in S. natalensis npi287, a mutant impaired in pimaricin production, was restored by supplementation with either A-factor from Streptomyces griseus IFO13350 or with PI factor. S. natalensis did not synthesize A-factor. The PI autoinducer was active at very low concentrations (50-350 nm). A threshold level of 50 nm was required to observe the induction effect. The dose-response curve was typical of a quorum-sensing type mechanism. The biosynthesis of PI factor was associated with cell growth of S. natalensis, both in defined and complex media. Supplementation of the wild-type S. natalensis with pure PI (300 nm) resulted in a stimulation of 33% of the production of pimaricin. These results indicate that the endogenous synthesis of PI factor is limiting for pimaricin biosynthesis in the wild-type strain. This water-soluble PI factor belongs to a novel class of autoinducers in Streptomyces species different from the classical butyrolactone autoinducers. Because restoration of pimaricin production in the npi287 mutant is conferred by both A-factor and PI factor, S. natalensis appears to be able to integrate different quorum signals from actinomycetes.
Structural effects on AVO: A modeling study (1998)

PreviousNext No AccessSEG Technical Program Expanded Abstracts 1998Structural effects on AVO: A modeling studyAuthors: Oong K. YounHua‐wei ZhouRobert E. SheriffOong K. YounUnocal, Hua‐wei ZhouExxon, and Robert E. SheriffAGL, University of Houstonhttps://doi.org/10.1190/1.1820330 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Permalink: https://doi.org/10.1190/1.1820330FiguresReferencesRelatedDetailsCited ByWavefield and AVO modeling using elastic thin-slab methodXian-Yun Wu and Ru-Shan Wu28 August 2006 | GEOPHYSICS, Vol. 71, No. 5 SEG Technical Program Expanded Abstracts 1998ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 1998 Pages: 2092 publication data© 1998 Copyright © 1998 Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished: 06 Jan 2005 CITATION INFORMATION Oong K. Youn, Hua‐wei Zhou, and Robert E. Sheriff, (1998), "Structural effects on AVO: A modeling study," SEG Technical Program Expanded Abstracts : 197-200. https://doi.org/10.1190/1.1820330 Plain-Language Summary PDF DownloadLoading ...
Presynaptically Expressed Long-Term Potentiation Increases Multivesicular Release at Parallel Fiber Synapses (2009)

At a number of synapses, long-term potentiation (LTP) can be expressed by an increase in presynaptic strength, but it is unknown whether presynaptic LTP is expressed solely through an increase in the probability that a single vesicle is released or whether it can increase multivesicular release (MVR). Here, we show that presynaptic LTP decreases inhibition of AMPA receptor EPSCs by a low-affinity antagonist at parallel fiber-molecular layer interneuron (PF-MLI) synapses. This indicates that LTP induction results in larger glutamate concentration transients in the synaptic cleft, a result indicative of MVR, and suggests that MVR can be modified by long-term plasticity. A similar decrease in inhibition was observed when release probability (PR) was increased by forskolin, elevated extracellular Ca2+, and paired-pulse facilitation. Furthermore, we show that MVR may occur under baseline physiological conditions, as inhibition increased when P(R) was lowered by reducing extracellular Ca2+ or by activating presynaptic adenosine receptors. These results suggest that at PF-MLI synapses, MVR occurs under control conditions and is increased when PR is elevated by both short- and long-term plasticity mechanisms.
Reachable set approach to collision avoidance for UAVs (2015)

In this paper, we propose a reachable set based collision avoidance algorithm for unmanned aerial vehicles (UAVs). UAVs have been deployed for agriculture research and management, surveillance and sensor coverage for threat detection and disaster search and rescue operations. It is essential for the aircraft to have on-board collision avoidance capability to guarantee safety. Instead of the traditional approach of collision avoidance between trajectories, we propose a collision avoidance scheme based on reachable sets and tubes. We then formulate the problem as a convex optimization problem seeking suitable control constraint sets for participating aircraft. We have applied the approach on a case study of two quadrotors collision avoidance scenario.
Atlantic hurricane trends linked to climate change (2006)

Increases in key measures of Atlantic hurricane activity over recent decades are believed to reflect, in large part, contemporaneous increases in tropical Atlantic warmth [ e.g., Emanuel , 2005]. Some recent studies [ e.g., Goldenberg et al. , 2001] have attributed these increases to a natural climate cycle termed the Atlantic Multidecadal Oscillation (AMO), while other studies suggest that climate change may instead be playing the dominant role [ Emanuel , 2005; Webster et al. , 2005]. Using a formal statistical analysis to separate the estimated influences of anthropogenic climate change from possible natural cyclical influences, this article presents results indicating that anthropogenic factors are likely responsible for long‐term trends in tropical Atlantic warmth and tropical cyclone activity. In addition, this analysis indicates that late twentieth century tropospheric aerosol cooling has offset a substantial fraction of anthropogenic warming in the region and has thus likely suppressed even greater potential increases in tropical cyclone activity.
Induction therapy for adults with acute lymphoblastic leukemia: results of more than 1500 patients from the international ALL trial: MRC UKALL XII/ECOG E2993 (2005)

The international acute lymphoblastic leukemia (ALL) study was designed to prospectively define the optimal therapy for adults 60 years of age or younger with newly diagnosed ALL. All patients received identical induction therapy, and 91% achieved complete remission (CR). Patients 50 years of age or younger with a compatible sibling were assigned to undergo allogeneic transplantation; the others were randomly assigned to autologous transplantation or to consolidation/maintenance therapy for 2.5 years. Patients who did not achieve CR after induction had an overall survival rate of 5% compared with 45% for patients who achieved CR. Factors at diagnosis predictive of overall survival and disease-free survival were age (P = .001), white blood cell count less than 30 x 10(9)/L for B lineage or less than 100 x 10(9)/L for T lineage (P = .001) and immunophenotype, T lineage versus B lineage (P = .001). The data demonstrate that achieving CR with induction therapy is indispensable for long-term survival in adult patients with ALL. Furthermore, with a response rate greater than 90%, the induction regimen was highly efficacious as remission-inducing therapy. This large database has validated several previously identified independent prognostic factors in ALL, such as age, white blood cell count at presentation, cytogenetics, and immunophenotype. However, the achievement of CR within 4 weeks does not appear to be an independent prognostic factor.
Understanding Threats to Scientific Openness (2003)

The scientific community is being confronted by public concerns that freely available scientific information may be exploited by terrorists. Differing points of view among scientists threaten to complicate discussion intended to address these concerns. Skepticism of the existence, breadth, and severity of the threat posed by would-be bioweaponeers is compounded by the failure to find clear evidence of biological weapons in Iraq. Also, some even question the extent to which open-source scientific material contributes to the threat. Recent public discussions regarding the potential for open-source science to enable bioterrorist activities have occurred in a vacuum, without examples of "real-world" activity. This is largely because the need for national security professionals to safeguard sources inculcates a culture of secrecy unlike the openness of the life science community. One potential contribution of the national security community is the opportunity albeit limited, to educate scientists regarding current and emerging threats through unclassified case studies. The following brief description of some recent findings provides insight into activities of potential exploiters and emphasizes the importance of closer interaction between the scientific and security communities. Documents recovered from an al-Qaida training camp in Afghanistan - (1) in 2001 have shed light on procedures and methodologies used by al-Qaida in its efforts to establish a biological warfare(BW) program. Individuals involved in this effort apparently relied on scientific research and information obtained collegially from public and private sources (see figure, above right) (2). Books found at the camp describe State sponsored BW activities and outline the history of biological warfare. The site also contained over 20 vintage research articles and medical publications from U.K. journals of the 1950s and '60s that provided a method for isolating, culturing, identifying, and producing bacteria, including Bacillus anthracis and Clostridium botulinum. Hand-written letters and BW primers found together at the same site suggest that al-Qaida's BW initiative included recruitment of individuals with Ph.D.-level expertise who supported planning and acquisition efforts by their familiarity with the scientific community.
<i>APOE</i>,<i>MAPT</i>, and<i>SNCA</i>Genes and Cognitive Performance in Parkinson Disease (2014)

Our data indicate that the APOE ε4 allele is an important predictor of cognitive function in PD across multiple domains. Among PD patients without dementia, the APOE ε4 allele was only associated with lower performance on word list learning and semantic verbal fluency, a pattern more typical of the cognitive deficits seen in early Alzheimer disease than PD.
High-efficiency microwave BJT power amplifier simulation (2003)

Simulation results of a Siemens BFP490 BJT power amplifier for a frequency range 8-11 GHz are presented. It was shown that the output network input impedance is inductive and the collector current is negative during a part of the AC cycle, when the amplifier operates in high-efficiency mode.
Surface and bulk-loss reduction research by low-energy hydrogen doping (1985)

Surface and bulk loss reduction by low energy hydrogen doping of silicon solar cells was examined. Hydrogen ions provided a suppression of space charge recombination currents. Implantation of hydrogen followed by the anneal cycle caused more redistribution of boron than the anneal which could complicate processing. It was demonstrated that passivation leads to space charge current reduction.
Ranking of Coordinate Terms and Hypernyms Using a Hypernym-Hyponym Dictionary (2014)

In this paper, methods for ranking coordinate terms and hypernyms of a given query according to their appropriateness are proposed. Although previous studies have proposed methods for discovering coordinate terms or hypernyms of a query, they focused on only discovering such terms and evaluating discovered terms based on a binary evaluation: appropriate or inappropriate. Unlike these studies, we rank coordinate terms and hypernyms of a query and evaluate the terms by considering their appropriateness. In the proposed method, a bipartite graph is created based on hypernyms of a query and hyponyms of each hypernym using a hypernym-hyponym dictionary. Subsequently, we apply a HITS-based algorithm to the bipartite graph and rank coordinate terms and hypernyms based on their appropriateness. The experimental results obtained using 50 queries demonstrate that our method could rank appropriate coordinate terms and hypernyms higher than other comparable methods.
CONTROL OF SILVERLEAF WHITEFLY AND INCIDENCE OF TOMATO YELLOW LEAF CURL VIRUS ON STAKED TOMATO WITH INSECTICIDES AND RESISTANT VARIETIES, 2006 (2007)

Silverleaf whitefly (SLW
Non‐Destructive Determination of the Structure and Composition of Glazes by Raman Spectroscopy (2005)

The utility of Raman spectroscopy as a non‐destructive technique for the characterization of glassy (alumino)silicates (modern or ancient glazes and glasses) is demonstrated. The addition of fluxing ions breaks the Si–O linkages and the degree of (de)polymerization determines the relative intensity of the Si–O bending and stretching modes and hence the degree of polymerization could be classified. The analysis can be used to predict the processing temperature of glasses. Bending ( Q ′ n ) and stretching ( Q n ) spectral components assigned to isolated ( Q 0 or SiO 4 ), and more or less connected SiO 4 vibrational units with one, two three/four bridging oxygen allow more precise analysis. The method is applied to reference modern porcelain glazes and selected ancient ceramic glazes and glasses, representative of the different production technologies used in the Asian, Islamic, and European worlds from Roman Empire to 19th century.
Computational investigation of the HIV‐1 Rev multimerization using molecular dynamics simulations and binding free energy calculations (2012)

The HIV Rev protein mediates the nuclear export of viral mRNA, and is thereby essential for the production of late viral proteins in the replication cycle. Rev forms a large organized multimeric protein-protein complex for proper functioning. Recently, the three-dimensional structures of a Rev dimer and tetramer have been resolved and provide the basis for a thorough structural analysis of the binding interaction. Here, molecular dynamics (MD) and binding free energy calculations were performed to elucidate the forces thriving dimerization and higher order multimerization of the Rev protein. It is found that despite the structural differences between each crystal structure, both display a similar behavior according to our calculations. Our analysis based on a molecular mechanics-generalized Born surface area (MM/GBSA) and a configurational entropy approach demonstrates that the higher order multimerization site is much weaker than the dimerization site. In addition, a quantitative hot spot analysis combined with a mutational analysis reveals the most contributing amino acid residues for protein interactions in agreement with experimental results. Additional residues were found in each interface, which are important for the protein interaction. The investigation of the thermodynamics of the Rev multimerization interactions performed here could be a further step in the development of novel antiretrovirals using structure based drug design. Moreover, the variability of the angle between each Rev monomer as measured during the MD simulations suggests a role of the Rev protein in allowing flexibility of the arginine rich domain (ARM) to accommodate RNA binding.
ChemInform Abstract: Optically Active Phenanthrolines in Asymmetric Catalysis. Part 3. Highly Efficient Enantioselective Transfer Hydrogenation of Acetophenone by Chiral Rhodium/3‐Alkylphenanthroline Catalysts. (1990)

Abstract The title phenanthrolines, e.g. (III) and (VI), are applied to the rhodium‐catalyzed transfer hydrogenation of the ketone (VII).
Evaluation of lumbar enlargement motor neuron excitability: Comparison between H-reflex and transcutaneous spinal cord stimulation (2016)

Multisegmental muscle responses (MMR) are reflexes in the leg muscles evoked by transcutaneous electrical spinal cord stimulation over the Th11–Th12 vertebrae. We have used MMR to evaluate the excitability of lumbosacral motor neurons in individuals having paraplegia of low limbs. Ten individuals were tested using H-reflexes and MMR bilaterally before (n 0 = 20) and during 4-weeks course of rehabilitation (n=76). The H-reflex and MMR of m. gastrocnemius lateralis were obtained in: 15 and 13 cases out of 20, respectively. Both reflexes were recorded in 11 and were absent in 3 cases, matched up to 70% of recordings. In dynamic, the both methods were 100% reproducible and the responses’ amplitude varied in similar directions in 67% of records. The data confirm the validity and reproducibility of the MMR for evaluation of the motor neurons excitability in lumbosacral cord. The H-reflex magnitude shows moderate correlation with MMR in m. gastrocnemius lateralis (r = 0.59, p < 0.001), and weak correlation with MMR in mm. rectus femoris, biceps femoris, and tibialis anterior (r < 0.40, p < 0.001). These findings do not allow extrapolate the results from the H-reflex measurement on the state of lumbosacral cord on the whole. At the same time, measurements of the MMR allow estimate simultaneously the excitability of motor pools innervating several muscle groups. This gives the possibility to assess the functional state of the motor neurons in the lumbosacral cord for clinical and experimental studies, including the spinal cord damage.
Gaussian reciprocal processes and self-adjoint stochastic differential equations of second order (1991)

Abstract We show that under suitable conditions the covariance of a Gaussian reciprocal process satisfies a self-adjoint linear differential equation of second order. We also give a revised definition of a linear stochastic differential equation of second order and necessary and sufficient conditions for the existence of solutions of such equations with Dirichlet boundary conditions. We close with a series of examples of the theory applied to the scalar stationary Gaussian Reciprocal processes which have been completely classified. Keywords: Gaussian reciprocal processessecond order stochastic differential equations
Operation of a 20 MW, 1 /spl mu/s,X-band gyroklystron (1991)

In the University of Maryland's Charged Particle Beam Lab, we are exploring the suitability of using gyroklystrons to drive future electron-positron supercolliders. The goal of our initial work was to increase the state-of-the-art in gyroklystrons by more than two-and-a-half orders of magnitude to the 20 MW level with suitable efficiency and gain. Major efforts have involved increasing the beam voltage above conventional gyrotron levels and enhancing the stability of the drift tube regions. We have achieved our goals in power level with a two-cavity 9.87 GHz configuration operating at 31 % efficiency and a gain of 26 dB in a tapered magnetic field. The nominal beam parameters to achieve these results are 425 kV, 150 A, and a beam alpha of 1.15. In this paper we will detail all essential aspects of the system. The operating parameters of the electron gun will be presented and compared with theory. The fabrication of lossy dielectrics will be described along with cold test results for all components. The types of tube instabilities and the methods of suppression will be categorized. Finally, amplification characteristics will be presented and compared to theory.
ChemInform Abstract: Metal Complexes of Functionalized Cyclodextrins as Enzyme Models and Chiral Receptors (1999)

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.
Controlled manipulation of oxygen vacancies using nanoscale flexoelectricity (2017)

Oxygen vacancies, especially their distribution, are directly coupled to the electromagnetic properties of oxides and related emergent functionalities that have implications for device applications. Here using a homoepitaxial strontium titanate thin film, we demonstrate a controlled manipulation of the oxygen vacancy distribution using the mechanical force from a scanning probe microscope tip. By combining Kelvin probe force microscopy imaging and phase-field simulations, we show that oxygen vacancies can move under a stress-gradient-induced depolarisation field. When tailored, this nanoscale flexoelectric effect enables a controlled spatial modulation. In motion, the scanning probe tip thereby deterministically reconfigures the spatial distribution of vacancies. The ability to locally manipulate oxygen vacancies on-demand provides a tool for the exploration of mesoscale quantum phenomena and engineering multifunctional oxide devices.The properties of complex oxides such as strontium titanate are strongly affected by the presence and distribution of oxygen vacancies. Here, the authors demonstrate that a scanning probe microscope tip can be used to manipulate vacancies by the flexoelectric effect.
Image transmission through a thick dynamic distorter by the photorefractive fanning effect (1998)

A new method of one-way image transmission through a thick dynamic distorter without the need for a reference beam or four-wave mixing is demonstrated. In this method there are only one object beam and one sampling beam. The response time of the photorefractive crystal must be much longer than the fluctuation period of the dynamic distorter. Thus the crystal responds only to the time-averaged intensity pattern of a rapidly varying object beam. The images, reconstructed with high fidelity, are picked up through the photorefractive fanning effect.
Estimating Densities of Grasshopper (Orthoptera: Acrididae) Assemblages Using Binomial Sampling (1993)

Counts of grasshoppers from Wyoming and New Mexico were related to the proportion of O.1−m 2 samples that contained grasshoppers through binomial sampling models. Three models were investigated. One was based on the Poisson probability density function and two were based on the Nachman and logit binomial regressions. The Nachman and logit regressions were tested extensively for an influence of predominant instar, sampling year, and location on the estimated parameters. Results indicated that instar and sampling year did not influence the parameter estimates, but location did. All models were then tested to determine which provided the smallest error for predicting densities from incidence and vice versa. Results showed that no differences occurred between models. Based on this finding, the Poisson sampling model was selected for use in wide-scale surveys because it is simple and easy to use. An independent data set from Montana was used to validate this model. Implications of this and other findings in context of using binomial sampling as a management and research tool are discussed.