gebhart/patrepeval huggingface dataset:
Enhanced Electron Transport in Dye-Sensitized Solar Cells Using Short ZnO Nanotips on A Rough Metal Anode (2009)

Many efforts have been directed toward the enhancement of electron transport in dye-sensitized solar cells (DSSC) using one-dimensional nanoarchitectured semiconductors. However, the improvement resulting from these ordered 1-D nanostructured electrodes is often offset or diminished by the deterioration in other device parameters intrinsically associated with the use of these 1-D nanostrucutres, such as the two-sided effect of the length of the nanowires impacting the series resistance and roughness factor. In this work, we mitigate this problem by allocating part of the roughness factor to the collecting anode instead of imparting all the roughness factors onto the semiconductor layer attached to the anode. A microscopically rough Zn microtip array is used as an electron-collecting anode on which ZnO nanotips are grown to serve as the semiconductor component of the DSSC. For the same surface roughness factor, our Zn-microtip|ZnO-nanotip DSSC exhibits an enhanced fill factor compared with DSSCs that have ZnO nanowires supported by a planar anode. In addition, the open-circuit voltage of the Zn-microtip|ZnO-nanotip DSSC is also improved due to a favorable band shift at the Zn−ZnO interface, which raises the Fermi level of the semiconductor and consequently enlarges the energy gap between the quasi-Fermi level of ZnO and the redox species. With these improvements, the overall efficiency becomes 1.4% with an open-circuit voltage of 770 mV, while the surface roughness factor of ZnO is approximately 60. Electrochemical impedance spectroscopic study reveals that the electron collection time is much shorter than the electron lifetime, suggesting that fast electron collection occurs in our device due to the significantly reduced electron collection distance along the short ZnO nanotips. The overall improvement demonstrates a new approach to enhance the efficiency of dye-sensitized solar cells.
A Formal Analysis and Taxonomy of Task Allocation in Multi-Robot Systems (2004)

Despite more than a decade of experimental work in multi-robot systems, important theoretical aspects of multi-robot coordination mechanisms have, to date, been largely untreated. To address this issue, we focus on the problem of multi-robot task allocation (MRTA). Most work on MRTA has been ad hoc and empirical, with many coordination architectures having been proposed and validated in a proof-of-concept fashion, but infrequently analyzed. With the goal of bringing objective grounding to this important area of research, we present a formal study of MRTA problems. A domain-independent taxonomy of MRTA problems is given, and it is shown how many such problems can be viewed as instances of other, well-studied, optimization problems. We demonstrate how relevant theory from operations research and combinatorial optimization can be used for analysis and greater understanding of existing approaches to task allocation, and to show how the same theory can be used in the synthesis of new approaches.
New Consensus Features for Tyrosine O-Sulfation Determined by Mutational Analysis (1997)

Tyrosine sulfation is an ubiquitous modification of proteins synthesized along the secretory pathway. It enhances protein-protein interactions and may be necessary for the bioactivity of secreted proteins and peptides. To predict tyrosine sulfation, a consensus has been proposed based on sequence comparisons of known substrates and on in vitro studies using synthetic peptides. This consensus predicts the presence of acidic residues on the amino-terminal side of the target tyrosine as the key feature. Using site-directed mutagenesis, we have examined the role of residues neighboring the sulfation site of an intact protein, human progastrin, in vivo. The results show that the charge of the residue in the amino-terminal position (-1) of the tyrosine is critical and can be neutral or acidic, whereas a basic residue abolishes sulfation. In addition, the degree of sulfation is influenced by the residues in positions -2 and -3. Hence, surprisingly a basic residue in position -2 enhances sulfation. Our data suggest a considerably broader range of substrates for the tyrosylprotein sulfotransferase than hitherto assumed and that the tyrosylprotein sulfotransferase is cell-specifically expressed.
Neptunium Extraction and Stability in the GANEX Solvent: 0.2 M TODGA/0.5 M DMDOHEMA/Kerosene (2012)

Abstract Batch distribution studies show that above ~1 M HNO3 Np(IV) and Np(VI) are well extracted into a solvent of 0.2 M TODGA/0.5 M DMDOHEMA in kerosene that has been formulated for the extraction of transuranic actinides in the GANEX (grouped actinide extraction) process. Np(IV) and Np(VI) are quite stable in the solvent phase, although Np(VI) is slowly reduced to Np(IV) on standing. Stripping of Np(IV,VI) ions from the GANEX solvent has been shown to be quite efficient using acetohydroxamic acid providing aqueous HNO3 concentrations are below ~0.3 M. In contrast, Np(V) shows much lower distribution ratios and is unstable in the GANEX solvent phase with quite rapid formation of Np(IV) observed. Closer analysis shows this to be due to Np(V) disproportionation, which is enhanced at higher organic phase acidities. Disproportionation of Np(V) is also shown to occur in separate TODGA and DMDOHEMA kerosene solutions. These observations thus enable conditions for neptunium extraction to be optimized during the design of a GANEX flowsheet. Keywords: neptuniumGANEXdisproportionationdistribution ratiosdiglycolamidemalonamide ACKNOWLEDGEMENTS Financial support for this work from European Framework Project “ACSEPT” (FP7-CP-2007-211 267), the National Nuclear Laboratory (IR&D Signature Research Programme Spent Fuel and Nuclear Materials), Sellafield Ltd. and the UK Nuclear Decommissioning Authority are gratefully acknowledged. Aritz Durana and Javier de Mendoza (ICIQ, Spain) are thanked for provision of TODGA. Fiona McLachlan (NNL) is thanked for calculations of HNO3 extraction.
A Selective and Mild Synthetic Route to Dialkyl Phosphates. (2003)

Abstract For Abstract see ChemInform Abstract in Full Text.
IFN-gamma receptor-Ig fusion proteins. Half-life, immunogenicity, and in vivo activity (1992)

Two mouse IFN-gamma receptor (MoIFN gamma R)-Ig fusion proteins, which were constructed for the purpose of creating new efficient mouse IFN-gamma (MoIFN-gamma) inhibitor molecules, were studied in vivo to determine their plasma half-life and immunogenicity, and to show their biologic activity. The hybrid proteins show 40-h blood persistency. They do not provoke an antibody response when injected into mice, and they are biologically active in vivo, as demonstrated by the prevention of streptozotocin-induced diabetes. The two fusion proteins are efficient MoIFN-gamma antagonists and can be used in mouse models of human diseases to investigate the role of MoIFN gamma in these pathologic states.
Regulation of neuronal differentiation by N‐methyl‐D‐aspartate receptors expressed in neural progenitor cells isolated from adult mouse hippocampus (2004)

In vitro culture of neural progenitor cells isolated from adult murine hippocampus according to the Percoll density gradient method resulted in formation of round spheres not immunoreactive to microtubule-associated protein-2 (MAP-2) or glial fibrillary acidic protein in the presence of basic fibroblast growth factor within 12 days in vitro (DIV). Reverse-transcription PCR analysis revealed constitutive expression in these neurospheres of different subunits required for assembly of functional heteromeric N-methyl-D-aspartate (NMDA) receptor channels. Immunocytochemical analysis confirmed expression of NR1, NR2A, and NR2B subunits in neurospheres cultured for 4-12 DIV. Brief (5 min) exposure to NMDA induced marked expression of c-Fos, Fos-B, Fra-2, and c-Jun proteins in neurospheres cultured for 12 DIV 2 hr later. The NMDA receptor antagonist dizocilpine markedly inhibited expression of both c-Jun and c-Fos proteins in NMDA-exposed neurospheres. Sustained exposure to NMDA not only markedly inhibited neurosphere formation by 12 DIV when exposed from 4-12 DIV, but also resulted in facilitation of subsequent differentiation of neurospheres exposed to all-trans retinoic acid to cells immunoreactive to both neuron-specific enolase and neuronal nuclei, in addition to MAP-2, as revealed by Western blot and immunocytochemistry analyses. These results suggest that functional heteromeric NMDA receptors may be expressed constitutively in neural progenitor cells before differentiation to play a crucial role in commitment and differentiation to neurons in adult murine hippocampus.
Fusion Loop Peptide of the West Nile Virus Envelope Protein Is Essential for Pathogenesis and Is Recognized by a Therapeutic Cross-Reactive Human Monoclonal Antibody (2009)

West Nile virus is an emerging pathogen that can cause fatal neurological disease. A recombinant human mAb, mAb11, has been described as a candidate for the prevention and treatment of West Nile disease. Using a yeast surface display epitope mapping assay and neutralization escape mutant, we show that mAb11 recognizes the fusion loop, at the distal end of domain II of the West Nile virus envelope protein. Ab mAb11 cross-reacts with all four dengue viruses and provides protection against dengue (serotypes 2 and 4) viruses. In contrast to the parental West Nile virus, a neutralization escape variant failed to cause lethal encephalitis (at higher infectious doses) or induce the inflammatory responses associated with blood-brain barrier permeability in mice, suggesting an important role for the fusion loop in viral pathogenesis. Our data demonstrate that an intact West Nile virus fusion loop is critical for virulence, and that human mAb11 targeting this region is efficacious against West Nile virus infection. These experiments define the molecular determinant on the envelope protein recognized by mAb11 and demonstrate the importance of this region in causing West Nile encephalitis.
Multiple fluorescence-based PCR-SSCP analysis. (1994)

Multiple fluorescence-based polymerase chain reaction single-strand conformation polymorphism (MF-PCR-SSCP) was developed. The target sequence was amplified by PCR using forward and reverse primers labeled with two different fluorescent dyes at their 5' ends. The amplified products were then heat-denatured, mixed with internal standard DNA markers labeled with a third fluorescent dye and applied to a temperature-controlled gel in an automated DNA sequencer, with a gel-temperature-controlling system. Mutations were detected as positional shifts of two-colored peaks in the electrophoretogram. The image data were analyzed by the computer program GENESCAN 672. The peak positions were standardized to internal DNA size markers. MF-PCR-SSCP analysis of 7 human tumor cell lines with 7 different single base mutations of the human K-ras oncogene detected all mutations even under the same electrophoresis conditions. Complete loss of heterozygosity was detected in two cell lines simultaneously. A gel temperature at 20 degrees C and polyacrylamide concentration of 10% gave the best separation. MF-PCR-SSCP is superior to the current PCR-SSCP in several ways: it does not involve radioactivity, migration patterns are standardized to internal standard DNA markers, there is a strict temperature-controlling system and the higher percentage of the gel enables better separation with resultant 100% detection of mutations most likely under one set of electrophoresis conditions.
Engineering of Quasi-Natural Pseudomonas putida Strains for Toluene Metabolism through an ortho -Cleavage Degradation Pathway (1998)

To construct a bacterial catalyst for bioconversion of toluene and several alkyl and chloro- and nitro-substituted derivatives into the corresponding benzoates, the upper TOL operon of plasmid pWW0 of Pseudomonas putida was fully reassembled as a single gene cassette along with its cognate regulatory gene, xylR. The corresponding DNA segment was then targeted to the chromosome of a P. putida strain by using a genetic technique that allows deletion of all recombinant tags inherited from previous cloning steps and leaves the otherwise natural strain bearing exclusively the DNA segment encoding the phenotype of interest. The resulting strains grew on toluene as the only carbon source through a two-step process: conversion of toluene into benzoate, mediated by the upper TOL enzymes, and further metabolism of benzoate through the housekeeping ortho-ring cleavage pathway of the catechol intermediate.
Fate of dietary sterols in hydrogenated oils and fats (1975)

Abstract Samples of table margarines, so‐called polyunsaturated table margarines, hydrogenated vegetable oils, and so‐called polyunsaturated hydrogenated vegetable oils were shown by infrared spectroscopy to contain hydrogenated components. Examination of the sterols from these oils by argentation thin layer chromatography and gas liquid chromatography did not reveal campestanol, stigmastanol, or Δ 22 ‐stigmastenol, the expected hydrogenation products of the natural sterols. The sterol compositions of the above samples, animal fats, and blends of hydrogenated vegetable oils and animal fats were determined. The compound 24‐methyl cholest‐7‐en‐3β‐ol was identified tentatively in sunflower and safflower oils.
Why are a3 ions rarely observed? (2008)

It has been determined experimentally that a(3) ions are generally not observed in the tandem mass spectroscopic (MS/MS) spectra of b(3) ions. This is in contrast to other b(n) ions, which often have the corresponding a(n) ion as the base peak in their MS/MS spectra. Although this might suggest a different structure for b(3) ions compared to that of other b(n) ions, theoretical calculations indicate the conventional oxazolone structure to be the lowest energy structure for the b(3) ion of AAAAR, as it is for other b(n) ions of this peptide. However, it has been determined theoretically that the a(3) ion is lower in energy than other a(n) ions, relative to the corresponding b ions. Furthermore, the a(3) --> b(2) transition structure (TS) is lower in energy than other a(n) --> b(n-1) TSs of AAAAR, compared with the corresponding b ions. Consequently, it is suggested that the b(3) ion does fragment to the a(3) ion, but that the a(3) ion then immediately fragments (to b(2) and a(3)) because of the excess internal energy arising from its relatively low energy and the facile a(3) --> b(2) reaction. That is why a(3) ions are not observed in the MS/MS spectra of b(3) ions.
Genetic characterization of Chinese measles vaccines by analysis of complete genomic sequences (2009)

The complete genomic sequences of two Chinese measles vaccine viruses, Shanghai-191 (S-191) and Changchun-47 (C-47), were determined and compared to the sequences of other measles vaccine strains as well as the prototype measles strain, Edmonston wild-type (Edwt). Compared to Edwt, S-191 and C-47 had 49 and 43 nucleotide changes, respectively. These differences were found at 52 nucleotide positions that were not found in other vaccine strains. Phylogenetic analysis of the all of the available genomic sequences for measles vaccines showed that S-191 and C-47 were most closely related to the Leningrad-4 strain. S-191 and C-47 shared conserved vaccine virus-specific amino acid changes in the phosphoprotein (P), V, C, matrix (M), and hemagglutinin (H) that could represent important targets for future studies aimed at understanding the molecular basis of attenuation. In addition, S-191 and C-47 had several unique amino acid changes including 13 positions that differed from Edwt. This is the first comparison of the complete genomic sequences of Chinese measles vaccines to the sequences of other vaccine strains.
Thyroid Receptor Ligands. 3. Design and Synthesis of 3,5-Dihalo-4-alkoxyphenylalkanoic Acids as Indirect Antagonists of the Thyroid Hormone Receptor (2005)

Based on the recently described concept of "indirect antagonism" of nuclear receptors, a series of thyroid hormone receptor (TR) antagonists were prepared, in which the outer ring of a thyromimetic was replaced with alkyl chains of variable length and branch. The results of a binding assay for the human TR and reporter cell assay revealed, within this series, a positive correlation between increasing bulk of the alkyl group and affinity to TRs. Compared with already reported TR antagonists, their affinities are within the same range, thus potentially representing a useful approach to novel and high affinity TR-antagonists.
Cytokine secretion by human fetal membranes, decidua and placenta at term (1998)

Cytokines such as monocyte chemotactic peptide-1 (MCP-1), interleukin-8 (IL-8), RANTES (Regulated on Activation and Normally T-cells Expressed and presumably Secreted) and interleukin-10 (IL-10) are thought to play pivotal roles in immune recognition, acceptance of the fetal allograft, maintenance of pregnancy and parturition. Their secretion and regulation within the third trimester uterus is, however, less well defined. We therefore investigated the release of these cytokines by third trimester amnion, chorion, placenta and decidua, and studied the influence of prostaglandin E2 (PGE2) infusion on their release in a dynamic placental cotyledon perfusion system. MCP-1 was released predominately by the chorion (78.2 +/- 7.3 pg/mg wet tissue weight; mean +/- SEM), decidua (112.4 +/- 5.2 pg/mg) and placenta (101.8 +/- 5.0 pg/mg) with low amounts from the amnion (1.3 +/- 0.4 pg/mg). High concentrations of IL-8 were released by the amnion (39.9 +/- 5.3 pg/mg), chorion (52.8 +/- 1.9 pg/mg), decidua (42.2 +/- 1.5 pg/mg) and placenta (45 +/- 1.3 pg/mg). Release of RANTES was not detectable from the amnion but was detected in moderate amounts from the chorion (6.0 +/- 1.2 pg/mg), decidua (15.2 +/- 1.4 pg/mg) and placenta (26.9 +/- 1.6 pg/mg). Low concentrations of IL-10 were secreted by the chorion (6.8 +/- 0.8 pg/mg), decidua (9.0 +/- 0.9 pg/mg) and placenta (3.3 +/- 0.3 pg/mg) with none detectable from the amnion. MCP-1, IL-8, RANTES and IL-10 were all released by perfused placental cotyledons. PGE2 stimulated release of MCP-1, IL-8 and IL-10 into the maternal and of MCP-1 and IL-8 into the fetal circulation of the placenta but had no effect on RANTES release. It is suggested that MCP-1 and IL-8 may be involved in the inflammatory process of parturition and IL-10 in the protection of the fetal allograft. In addition, PGE2 may have an important immunomodulatory role within the uterus at term.
Pyrimidine annelated heterocycles - synthesis and cycloaddition of the first pyrimido[1,4]diazepine N-oxides (2001)

5-Formyl- and 5-acetyl-4-(alkenylamino)pyrimidines 5 have been prepared as precursors to novel pyrimido[1,4]diazepine N-oxides 3. In addition to cyclisation to the targeted dipoles the substrates 5 have also been observed to form imidazopyrimidines 12 and 39via an intramolecular Michael addition; additionally 5b has been observed to form the pyrimidoazepinone 42. Aldonitrone 3a cycloadded readily to olefinic dipolarophiles; ketodipole 3b did not share this reactivity. Both dipoles reacted with acetylenic dipolarophiles but the ensuing cycloadducts 37 were unstable; facile ring contraction of their isoxazolopyrimidodiazepine skeletons to the pteridine nucleus is noted. The structure of 37c has been determined by X-ray crystallography.
A mutation in the extracellular domain of the insulin receptor impairs the ability of insulin to stimulate receptor autophosphorylation. (1991)

Mutations of the insulin receptor gene have been shown to cause insulin-resistant diabetes in patients with genetic forms of insulin resistance. We have previously reported that a mutation substituting valine for Phe382 in the alpha-subunit of the insulin receptor is associated with impaired transport of the mutant receptor to the plasma membrane (Accili, D., Frapier, C., Mosthaf, L., McKeon, C., Elbein, S. C., Permutt, M. A., Ramos, E., Lander, E. S., Ullrich, A., and Taylor, S. I. (1989) EMBO J. 8, 2509-2517). In this study, we demonstrate that the Val382 mutation impairs the ability of insulin to activate receptor autophosphorylation. Furthermore, the Val382 receptor has reduced activity to phosphorylate other peptide substrates in the presence of insulin. Nevertheless, when the Val382 mutant and wild-type receptors are mixed together, the wild-type human insulin receptor is able to phosphorylate the Val382 mutant receptor, thereby activating the tyrosine kinase activity of the mutant receptor. Thus, the conformational change caused by the Val382 mutation compromises the ability of the receptor to transmit a signal across the plasma membrane. Furthermore, our observations suggest that receptor phosphorylation by an intermolecular mechanism (i.e. transphosphorylation) may play a role in mediating the action of insulin upon the target cell.
The chemistry of methanol on the TiO2(110) surface: the influence of vacancies and coadsorbed species (1999)

The chemistry of methanol was explored on the vacuum annealed TiO2(110) surface, with and without the presence of coadsorbed water and oxygen, using temperature programmed desorption (TPD), high resolution electron energy loss spectroscopy (HREELS), static secondary ion mass spectrometry (SSIMS) and low energy electron diffraction (LEED). The vacuum annealed TiO2(110) surface possessed about 8% oxygen vacancy sites, as determined with H2O TPD. Although evidence is presented for CH3OH dissociation to methoxy groups on the vacuum annealed TiO2(110) surface using SSIMS and HREELS, particularly at vacancy sites, the majority of the adlayer was molecularly adsorbed, evolving in TPD at 295 K. Although no evidence of irreversible decomposition was found in the TPD, dissociative CH3OH adsorption at 135 K on the vacuum annealed TiO2(110) surface led to recombinative desorption states at 350 and 480 K corresponding to methoxys adsorbed at non-vacancy and vacancy sites, respectively. Coadsorbed water had little or no influence on the chemistry of CH3OH on the vacuum annealed TiO2(110) surface, however new channels of chemistry were observed when CH3OH was adsorbed on the surface after O2 adsorption at various temperatures. In particular, O2 exposure at 300 K resulted in O adatoms (via dissociation at vacancies) that led to increased levels of CH3O–H bond cleavage. The higher surface coverage of methoxy then resulted in a disproportionation reaction to form CH3OH and H2CO above 600 K. In contrast, low temperature exposure of the vacuum annealed TiO2(110) surface to O2 resulted in low temperature state of O2 (presumably an O2- species) that oxidized CH3OH to H2CO by C–H bond cleavage. These results provide incentive to consider alternative thermal and photochemical oxidation mechanisms that involve the interaction of organics and oxygen at surface defect sites.