gebhart/patrepeval huggingface dataset:
Temperature Quenching of Yellow Ce3+ Luminescence in YAG:Ce (2009)

Yttrium aluminum garnet (YAG) doped with Ce3+ is the phosphor of choice for the conversion of blue to yellow light in the rapidly expanding market of white light LEDs, but it is generally thought to suffer from a low luminescence quenching temperature. The luminescence quenching temperature is an important parameter, especially in high-power LEDs, but surprisingly no systematic research has been done to measure and understand the temperature quenching of the yellow Ce luminescence in YAG:Ce. Here we report on the luminescence temperature quenching in YAG:Ce. For a wide range of Ce concentrations (between 0.033% and 3.3%) the temperature dependence of the emission intensity and the luminescence lifetimes are reported. The intrinsic quenching temperature of the Ce luminescence is shown to be very high (>700 K). The lower quenching temperatures reported in the literature are explained by thermally activated concentration quenching (for highly doped systems) and the temperature dependence of the oscillator strength (for low doping concentrations). In addition, high-resolution spectra are reported, which provide insight into the position of the zero-phonon transition (20450 cm−1), the Stokes shift (2400 cm−1), the energy of the dominant phonon mode (200 cm−1), and the Huang−Rhys parameter (S = 6). These parameters are compared with ab initio calculations on the position of and relaxation in the excited 5d state of Ce3+ in YAG, which can aid in providing a better theoretical understanding of the temperature quenching.
2px-ray absorption of 3dtransition-metal compounds: An atomic multiplet description including the crystal field (1990)

The metal 2p x-ray-absorption spectra (or ${\mathit{L}}_{2,3}$ edges) of 3d transition-metal compounds are calculated, using atomic multiplet theory with inclusion of the cubic crystal field. A general overview of the effect of the cubic crystal field on the shape of the 3${\mathit{d}}^{\mathit{N}}$ to 2${\mathit{p}}^{5}$3${\mathit{d}}^{\mathit{N}+1}$ excitation spectrum is given for 14 common valencies of 3d transition-metal ions. Comparison to some high-resolution 2p x-ray-absorption spectra shows excellent agreement, which confirms the validity of the approach. Possible refinements of the theory, including lower-symmetry calculations and the inclusion of configuration interaction, are discussed.
Force Tracking in Impedance Control (1997)

This article presents two simple on-line schemes for force tracking within the impedance-control framework. The force- tracking capability of impedance control is particularly important for providing robustness in the presence of large uncertainties or variations in environmental parameters. The two proposed schemes generate the reference position trajec tory required to produce a desired contact force despite lack of knowledge of the environmental stiffness and location. The first scheme uses direct adaptive control to generate the refer ence position on-line as a function of the force-tracking error. Alternatively, the second scheme utilizes an indirect adaptive strategy in which the environmental parameters are estimated on-line, and the required reference position is computed based on these estimates. In both schemes, adaptation allows au tomatic gain adjustment to provide a uniform performance despite variations in the environmental parameters. Simula tion studies are presented for a 7-DOF Robotics Research arm using full arm dynamics, demonstrating that the adaptive schemes are able to compensate for uncertainties in both the environmental stiffness and location. The simulation studies also highlight the limitations of pure impedance control without the force-tracking capability for robust execution of realistic contact tasks. Experimental results are also presented for the Robotics Research arm to demonstrate that the end effector applies the desired contact force while exhibiting the specified impedance dynamics.
Synthesis of Water-Soluble Dendrimers Based on Melamine Bearing 16 Paclitaxel Groups (2007)

The design, synthesis, and characterization of triazine dendrimers derivatized with the anticancer agent paclitaxel are described. The precursor generation two dendrimer 1 is prepared in six linear steps in 64% overall yield and presents 16 amines and two groups for radioiodination. This macromolecule is subsequently derivatized with a paclitaxel conjugate to yield a generation three dendrimer, 2, which is then pegylated in two steps. The pegylated final products, 4a and 4b, with molecular weights of 46 and 77 kDa, respectively, solubilize paclitaxel in water. Pegylated dendrimer 4a is 30 wt % paclitaxel, 52 wt % PEG, and 18 wt % dendrimer. Target 4b is 18 wt % paclitaxel, 71 wt % PEG, and 11 wt % dendrimer.
Comparison of the Mechanism of Toxicity of Zinc Oxide and Cerium Oxide Nanoparticles Based on Dissolution and Oxidative Stress Properties (2008)

Nanomaterials (NM) exhibit novel physicochemical properties that determine their interaction with biological substrates and processes. Three metal oxide nanoparticles that are currently being produced in high tonnage, TiO(2), ZnO, and CeO(2), were synthesized by flame spray pyrolysis process and compared in a mechanistic study to elucidate the physicochemical characteristics that determine cellular uptake, subcellular localization, and toxic effects based on a test paradigm that was originally developed for oxidative stress and cytotoxicity in RAW 264.7 and BEAS-2B cell lines. ZnO induced toxicity in both cells, leading to the generation of reactive oxygen species (ROS), oxidant injury, excitation of inflammation, and cell death. Using ICP-MS and fluorescent-labeled ZnO, it is found that ZnO dissolution could happen in culture medium and endosomes. Nondissolved ZnO nanoparticles enter caveolae in BEAS-2B but enter lysosomes in RAW 264.7 cells in which smaller particle remnants dissolve. In contrast, fluorescent-labeled CeO(2) nanoparticles were taken up intact into caveolin-1 and LAMP-1 positive endosomal compartments, respectively, in BEAS-2B and RAW 264.7 cells, without inflammation or cytotoxicity. Instead, CeO(2) suppressed ROS production and induced cellular resistance to an exogenous source of oxidative stress. Fluorescent-labeled TiO(2) was processed by the same uptake pathways as CeO(2) but did not elicit any adverse or protective effects. These results demonstrate that metal oxide nanoparticles induce a range of biological responses that vary from cytotoxic to cytoprotective and can only be properly understood by using a tiered test strategy such as we developed for oxidative stress and adapted to study other aspects of nanoparticle toxicity.
Improving Visual Sensitivity with Subthreshold Transcranial Magnetic Stimulation (2011)

We probed for improvement of visual sensitivity in human participants using transcranial magnetic stimulation (TMS). Stimulation of visual cortex can induce an illusory visual percept known as a phosphene. It is known that TMS, delivered at intensities above the threshold to induce phosphenes, impairs the detection of visual stimuli. We investigated how the detection of a simple visual stimulus is affected by TMS applied to visual cortex at or below the phosphene threshold. Participants performed the detection task while the contrast of the visual stimulus was varied from trial to trial according to an adaptive staircase procedure. Detection of the stimulus was enhanced when a single pulse of TMS was delivered to the contralateral visual cortex 100 or 120 ms after stimulus onset at intensities just below the phosphene threshold. No improvement in visual sensitivity was observed when TMS was applied to the visual cortex in the opposite hemisphere (ipsilateral to the visual stimulus). We conclude that TMS-induced neuronal activity can sum with stimulus-evoked activity to augment visual perception.
Monocyte chemoattractant protein-1 in human atheromatous plaques. (1991)

Monocytes appear to be central to atherogenesis both as the progenitors of foam cells and as a potential source of growth factors mediating intimal hyperplasia, but the chemical messages which stimulate the influx of monocytes into human atheroma remain unknown. Monocyte chemoattractant protein-1 (MCP-1) is a recently described molecule with powerful monocyte chemotactic activity expressed by monocytes, vascular endothelial cells, and smooth muscle cells in culture. To begin to address the role of MCP-1 in vivo, we examined 10 normal arteries and 14 diseased human arteries for MCP-1 expression by in situ hybridization. MCP-1 mRNA was detected in 16% of 10,768 cells counted in human carotid endarterectomy specimens with highest expression seen in organizing thrombi (33%) and in macrophage rich areas bordering the necrotic lipid core (24%) as compared to the fibrous cap (8%) and the necrotic lipid core itself (5%). Based on immunohistochemical staining of serial sections and on cell morphology, MCP-1 mRNA appeared to be expressed by vascular smooth muscle cells (VSMC), mesenchymal appearing intimal cells (MICs), and macrophages. By contrast, few cells expressing MCP-1 mRNA were found in normal arteries (less than 0.1%). These data suggest a potential role for MCP-1 in mediating monocytic infiltration of the artery wall.
Selected isothiocyanates rapidly induce growth inhibition of cancer cells. (2003)

Many plant-derived isothiocyanates (ITCs), which occur in human diet, are potent cancer chemopreventive agents in animals. Among the anticarcinogenic mechanisms that have been revealed for ITCs is the inhibition of cell proliferation. We report that exposure of cancer cells to either allyl-ITC (AITC), benzyl-ITC (BITC), or phenethyl-ITC (PEITC) for only 3 h was long enough for the inhibition of cell growth, based on a comparison of IC50 values; regardless of the origin of cancer cells; and even in drug-resistant cells that overexpressed multidrug resistance associated protein-1 (MRP-1) or P-glycoprotein-1 (Pgp-1). In contrast, the inhibitory effect of another ITC, sulforaphane (SF), on these cells was highly time dependent. The finding that some ITCs could inhibit the proliferation of cancer cells in a largely time-independent manner is significant because ITCs that enter the human body are rapidly cleared through urinary excretion. Using human promyelocytic leukemia HL60/S as model cells, and focusing on AITC and BITC, we found that these ITCs modulated multiple cellular targets involved in proliferation, including the disruption of mitochondrial membrane potential, activation of multiple caspases, arrest of cell cycle progression, and induction of differentiation. Again, only a 3-h incubation of the cells with the ITCs was enough to exert their full effect on these targets. Taken together, our findings suggest that selected ITCs can rapidly initiate growth inhibition of cancer cells by simultaneously modulating multiple cellular targets, and their antiproliferative activity may be largely unaffected by their metabolism and disposition in vivo.
Imaging of optical inhomogeneities in highly diffusive media: Discrimination between scattering and absorption contributions (1996)

An effective projection imaging technique is proposed that allows not only detection of realistic optical inhomogeneities in highly diffusive media, but also the discrimination between scattering and absorption contributions. The method is based on information derived from time-resolved transmittance measurements. Scattering inhomogeneities are discriminated using maps of the transport scattering coefficient, as provided by best fitting of the diffusion theory to experimental data. Absorption variations are effectively classified by time gating on the tail of the transmittance pulse.
Control of Immunoglobulin Class Switch Recombination (1986)

The comparative analysis of Ig class switch recombination in a priori IgG/IgA-expressing myelomas and hybridomas, in switch variants and in activated normal B cells shows the following characteristics of class switch recombination in activated B cells: It is prevented during most of B cell ontogeny. It happens on both IgH loci of activated and switched B cells. The recombination is programmed in that on both IgH loci of switched cells the same switch regions recombine with Smu. This is true at least for the IgG1 pathway. IgM-expressing cells show no class switch recombination on the inactive IgH locus. Thus, physiological class switch recombination is a programmed rather than a random event and is controlled as such. The initial stages of class switching and the molecules involved in these are largely unclear: What is the nature of the protection of switch regions and how is this protection abrogated? Do specific recombinases exist? What is the role of large transcription units? Is the specificity of class switch recombination a result of specific "opening" of the DNA for transcription? Do all B cells use the same switch mechanism? What is the role of switch factors (such as lymphokines)? These and more questions await answers and although a variety of switch scenarios could be discussed at present a detailed speculation seems premature.
Influence of Binaural Beats on EEG Signal (2011)

Binaural beats are subjective hearing sensations, which occur when one of tone signals is applied to one ear, and the other one, with a slightly different frequency is applied to the second ear. A listener then receives a resultant sound with an amplitude which changes with a frequency equal to the difference of frequency of applied signals. The aim of this thesis was to examine the influence of binaural beats on changes in the morphology of the brain bioelectrical signal. Verification of previous studies, such as stimulation of binaural beats affects the brain and can cause changes in other frequency bands. Previous studies have been conducted on individual leads and dealt with the occurrence of follow up effect. In the research there were used binaural beats with a frequency of f = 10 Hz. The left ear was exposed to a signal with a frequency of 100 Hz, and the right ear -to a signal with a frequency of 110 Hz, the acoustic pressure level SPL = 73 dB. The research was conducted on a sample group of 20 people. The analysis of average amplitudes of spectral density function of EEG strength signal proved that the exposition of binaural beats brought about a follow-up effect, which means that a component frequency in the EEG signal morphology was observed which corresponds with a frequency of the exposed binaural beats. It was also noted that during the exposition of binaural beats, there occurs a statistically significant decrease of average amplitudes of spectral density function of EEG strength signal for alpha and beta frequency ranges. However, it was observed that the amplitude of spectral density function of the strength has increased in theta frequency range.
Evidence of endogenous regulatory function of transforming growth factor-β1 in experimental allergic encephalomyelitis (1992)

Experimental allergic encephalomyelitis (EAE) is an autoimmune disease characterized by inflammation and demyelination in the central nervous system (CNS). Administration of transforming growth factor-beta (TGF-beta) has been shown to inhibit EAE. In this study, the possible role of endogenous TGF-beta in the regulation of relapsing EAE produced by the transfer of myelin basic protein-specific T cell lines was assessed. Although TGF-beta is not present in the normal CNS, this cytokine was detected by immunohistology in areas of central nervous system inflammation in both acute and chronic disease. The administration of anti-TGF-beta at the disease onset led to a worsening of the clinical course of EAE and more extensive pathological lesions. These findings provide direct evidence for a role of endogenous TGF-beta in the remissions seen in chronic relapsing EAE.
Nuclear IFI16 induction of IRF-3 signaling during herpesviral infection and degradation of IFI16 by the viral ICP0 protein (2012)

Innate sensing of microbial components is well documented to occur at many cellular sites, including at the cell surface, in the cytosol, and in intracellular vesicles, but there is limited evidence of nuclear innate signaling. In this study we have defined the mechanisms of interferon regulatory factor-3 (IRF-3) signaling in primary human foreskin fibroblasts (HFF) infected with herpes simplex virus 1 (HSV-1) in the absence of viral gene expression. We found that the interferon inducible protein 16 (IFI16) DNA sensor, which is required for induction of IRF-3 signaling in these cells, is nuclear, and its localization does not change detectably upon HSV-1 d109 infection and induction of IRF-3 signaling. Consistent with the IFI16 sensor being nuclear, conditions that block viral DNA release from incoming capsids inhibit IRF-3 signaling. An unknown factor must be exported from the nucleus to activate IRF-3 through cytoplasmic STING, which is required for IRF-3 activation and signaling. However, when the viral ICP0 protein is expressed in the nucleus, it causes the nuclear relocalization and degradation of IFI16, inhibiting IRF-3 signaling. Therefore, HSV-1 infection is sensed in HFF by nuclear IFI16 upon release of encapsidated viral DNA into the nucleus, and the viral nuclear ICP0 protein can inhibit the process by targeting IFI16 for degradation. Together these results define a pathway for nuclear innate sensing of HSV DNA by IFI16 in infected HFF and document a mechanism by which a virus can block this nuclear innate response.
Localized Structural Alterations Underlying a Subset of Unexplained Sudden Cardiac Death (2018)

This study shows that localized structural alterations underlie a significant subset of previously unexplained sudden cardiac death. In the other subset, Purkinje electrical pathology seems as a dominant mechanism.
GT to AT transition at a splice donor site causes skipping of the preceding exon in Phenylketonuria (1987)

Classical Phenylketonuria (PKU) is an autosomal recessive human genetic disorder caused by a deficiency of hepatic phenylalanine hydroxylase (PAH). We isolated several mutant PAH cDNA clones from a PKU carrier individual and showed that they contained an internal 116 base pair deletion, corresponding precisely to exon 12 of the human chromosomal PAH gene. The deletion causes the synthesis of a truncated protein lacking the C-terminal 52 amino acids. Gene transfer and expression studies using the mutant PAH cDNA indicated that the deletion abolishes PAH activity in the cell as a result of protein instability. To determine the molecular basis of the deletion, the mutant chromosomal PAH gene was isolated from this individual and shown to contain a GT-- greater than AT substitution at the 5' splice donor site of intron 12. Thus, the consequence of the splice donor site mutation in the human liver is the skipping of the preceding exon during RNA splicing.
Δ4,4‘-Dicyclopenta[2,1-b:3,4-b‘]dithiophene. A Conjugated Bridging Unit for Low Band Gap Conducting Polymers (2003)

Δ4,4‘-Dicyclopenta[2,1-b:3,4-b‘]dithiophene has been prepared from cyclopenta[2,1-b:3,4-b‘]bithiophen-4-one and its electrochemical and spectroscopic properties have been characterized. Its low HOMO−LUMO gap and facile electrochemical polymerization make it an attractive building block for low band gap conducting polymers. Films of poly-(Δ4,4‘-dicyclopenta[2,1-b:3,4-b‘]dithiophene) on electrodes have been characterized by cyclic voltammetry, electronic absorption spectroscopy, IR spectroscopy, and in situ conductivity measurements. The spectroscopic and electrochemical results confirm the formation of a polymeric material with long conjugation length and low band gap (ca. 0.5 eV). The intrinsic conductivity is consistent with this band gap.
Synthesis of some d0 organoimido complexes of the early transition metals (1983)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of some d0 organoimido complexes of the early transition metalsWilliam A. NugentCite this: Inorg. Chem. 1983, 22, 6, 965–969Publication Date (Print):March 1, 1983Publication History Published online1 May 2002Published inissue 1 March 1983https://pubs.acs.org/doi/10.1021/ic00148a023https://doi.org/10.1021/ic00148a023research-articleACS PublicationsRequest reuse permissionsArticle Views867Altmetric-Citations92LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Determination of the Local Chemical Structure of Graphene Oxide and Reduced Graphene Oxide (2010)

The local atomic structure of graphene oxide (GO) and reduced annealed graphene oxide (raGO) is determined via ultra-high-resolution transmission electron microscopy. We find that the proposed and desired return to graphene from GO is not possible through the synthetic route employed. The detailed structure of GO, previously unknown, is revealed as mottled, with few square nanometer graphitic regions separated by highly oxidized regions.
Identification of combinatorial drug regimens for treatment of Huntington's disease using Drosophila (2005)

We explore the hypothesis that pathology of Huntington's disease involves multiple cellular mechanisms whose contributions to disease are incrementally additive or synergistic. We provide evidence that the photoreceptor neuron degeneration seen in flies expressing mutant human huntingtin correlates with widespread degenerative events in the Drosophila CNS. We use a Drosophila Huntington's disease model to establish dose regimens and protocols to assess the effectiveness of drug combinations used at low threshold concentrations. These proof of principle studies identify at least two potential combinatorial treatment options and illustrate a rapid and cost-effective paradigm for testing and optimizing combinatorial drug therapies while reducing side effects for patients with neurodegenerative disease. The potential for using prescreening in Drosophila to inform combinatorial therapies that are most likely to be effective for testing in mammals is discussed.