gebhart/patrepeval huggingface dataset:
A molecular mechanics study of dioxygen binding by lacunar cobalt dioxygen carriers (1991)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA molecular mechanics study of dioxygen binding by lacunar cobalt dioxygen carriersWang Kan Lin, Nathaniel W. Alcock, and Daryle H. BuschCite this: J. Am. Chem. Soc. 1991, 113, 20, 7603–7608Publication Date (Print):September 1, 1991Publication History Published online1 May 2002Published inissue 1 September 1991https://pubs.acs.org/doi/10.1021/ja00020a023https://doi.org/10.1021/ja00020a023research-articleACS PublicationsRequest reuse permissionsArticle Views116Altmetric-Citations30LEARN 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-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
Cuttings of a tobacco mutant, rae, undergo cell divisions but do not initiate adventitious roots in response to exogenous auxin (1996)

Numerous studies have shown that auxin induces adventitious root initiation in stem explants from a variety of species, including tobacco. A dominant, monogenic mutation previously identified in tobacco ( Nicotiana tabacum cv. Xanthii), rac , confers tenfold auxin resistance to mesophyll‐derived cell suspensions and an impaired primary root development phenotype to seedlings. Results presented here demonstrate that adventitious root formation does not occur when heterozygous and homozygous rac stem cuttings are treated in vitro with indole‐3‐butyric acid (IBA) concentrations ranging from 0.5 μ M to 500 μ M . Histological analysis showed that some phloem parenchyma or inner cortical parenchyma cells in wild‐type stem cuttings undergo adventitious root morphogenesis when they are treated with 5 μ M IBA. The same cell types in heterozygous and homozygous rac stem cuttings undergo mitoses in response to auxin, but never form adventitious root meristems. The lack of adventitious root initiation in rac stem cuttings is phenotypically distinct from the aberrant primary root development in rac seedlings. The rac mutation appears to block an essential process for auxin induction of adventitious root initiation but not cell division in phloem parenchyma or inner cortical parenchyma cells. Comparisons of rac heterozygous and homozygous seedling primary root length and callus formation in response to auxin in stem cuttings indicate that rac copy number is correlated to the degree of expression of these two phenotypes.
A 2.3 GSample/s 10-tap digital FIR filter for magnetic recording read channels (2002)

A 6 b 10 tap 2.3 GSample/s distributed-arithmetic digital FIR filter uses footless dynamic logic with delayed reset for precharge. The 0.5 mm/sup 2/ filter, fabricated in 0.18 /spl mu/m CMOS, is operational from 1 V to 2 V power supply. At 2.3 GSample/s, the power is 680 mW, and at 1 GSample/s the power is 120 mW.
Ethylene insertion and .beta.-hydrogen elimination for permethylscandocene alkyl complexes. A study of the chain propagation and termination steps in Ziegler-Natta polymerization of ethylene (1990)

The rates of ethylene insertion into the Sc-C bond for Cp*_2ScR (Cp* = (η^5-C_5Me_5), R = CH_3, CH_2CH_3, CH_2CH_2CH_3) have been measured at -80 °C by ^(13)C NMR; the second order rate constants (M^(-1) S^(-1)) are as follows: R = CH_3, 8.1 (2) X 10^(-4); R = CH_2CH_3,4.4 (2) X 10^(-4); R = CH_2CH_2CH_3, 6.1 (2) X 10^(-3). The slow rate for the ScCH_2CH_3 complex is attributed to a ground-state stabilization by a β-C-H "agostic” interaction. The distributions of molecular weights for ethylene oligomers (CH_3(CH_2)_nCH_3, n = 11-47) produced from known amounts of ethylene and Cp*_2ScCH_2CH_2CH_3 at -80 °C satisfactorily fit a Poisson distribution, indicative of a “living” Ziegler-Natta polymerization system. From the measured, slower initiation rates of insertion for Cp*ScCH_3 and Cp*_2ScCH_2CH_3 and propagation rates equal to that for Cp_2ScCH_2CH_2CH_3, the molecular weight distributions of ethylene oligomers are also accurately predicted. Cp*ScCH_3 undergoes a single insertion with 2-butyne with a moderate enthalpy of activation and a large, negative entropy of activation. The second-order rate constants for the insertion of 3-phenyl-2-propyne, 2-pentyne, and 4-methyl-2-pentyne have been measured. The rates for &amp;hydrogen elimination for members of the series of permethylscandocene alkyl complexes Cp*_2ScCH_2CH_2R (R = H, CH_3, CH_2CH_3, C_6H_5, C_6H_4-p-CH_3, C_6H_4-p-CF_3, C_6H_4-p-NMe_2) have been obtained by rapidly trapping Cp*ScH with 2-butyne. A transition state for the β-hydrogen elimination is indicated with partial charge on the &amp;carbon. Hydrogen is thus transferred to the scandium center as hydride in the β-H elimination process.
Hazard assessment of polymer-capped CuO and ZnO nanocolloids: A contribution to the safe-by-design implementation of biocidal agents (2019)

The antibacterial activity of metal oxide (MeO) nanoparticles (NPs) has been extensively reported. Nevertheless, there is a general concern about MeO NPs toxicity, and much efforts are being devoted to improve a safe employment of these nanomaterials by surface functionalization. In this work, we propose to investigate if the coating of copper and zinc oxides (CuO and ZnO) NPs with the polymers poly(ethylene imine) (PEI) or poly(ethylene glycol) (PEG) is able protect non-target cells and organisms from the toxicity of antibacterial MeOs NPs. The overall results obtained exposing lung cells and Xenopus laevis embryos to CuO-PEG, CuO-PEI, ZnO-PEG and ZnO-PEI, indicate that PEG, but not PEI coating, is able to exert a protective function against MeOs toxicity. The ability of PEG shell to reduce the adverse impact of MeOs NPs is in part associated to a protection from the oxidative stress, even if in vitro results indicate that peghylation is not able to prevent pro-inflammatory responses. We suggest that the different intracellular availability of the metal oxides upon capping with PEG or PEI, together with the involvement of multiple mechanisms of action, may be responsible for the different toxicological outcome on lung cells viability and Xenopus mortality and malformations.
Inhibition of monoterpene cyclases by sulfonium analogs of presumptive carbocationic intermediates of the cyclization reaction. (1986)

The enzymatic cyclization of geranyl pyrophosphate to monoterpenes is thought to proceed through a series of carbocation-pyrophosphate anion paired intermediates. Sulfonium analogs of two putative carbocationic intermediates of the cyclization sequence were shown to be inhibitors of the conversion of the acyclic precursor to the bicyclic monoterpenes (+)-alpha-pinene and (+)-bornyl pyrophosphate by partially purified cyclase preparations from sage (Salvia officinalis). The sulfonium analog of the tertiary allylic, linalyl, intermediate (i.e. methyl-(4-methylpent-3-en-1-yl)vinyl-sulfonium perchlorate) provided respective Ki values of 2.5 microM and 3.0 microM against the cyclization to alpha-pinene and bornyl pyrophosphate at a substrate concentration of 5 microM, whereas the sulfonium analog of the monocyclic, alpha-terpinyl, intermediate (i.e. dimethyl-(4-methylcyclohex-3-en-1-yl) sulfonium iodide) exhibited respective Ki values of 3.4 microM and 3.9 microM against the same two cyclizations. The potency of inhibition in all cases increased with increasing substrate concentration, indicating that the affinity of the enzymes for the sulfonium analogs was increased by the presence of the pyrophosphate ester. Inorganic pyrophosphate at a concentration of 50 microM, which alone had little influence on the cyclizations, increased the effectiveness of inhibition of the sulfonium analogs severalfold, and the apparent Ki for inorganic pyrophosphate was reduced manyfold by the presence of either analog at 5 microM. That the combination of sulfonium analog and pyrophosphate provided synergistic inhibition of the electrophilic cyclizations indicated that the cyclases bind the paired species more tightly than either partner alone. Specificity studies suggested that inhibition by the above sulfonium ion:pyrophosphate pairs was due to both electronic and structural resemblance to intermediates of the reaction.
Spatially selective photoconductive stimulation of live neurons (2014)

Synaptic activity is intimately linked to neuronal structure and function. Stimulation of live cultured primary neurons, coupled with fluorescent indicator imaging, is a powerful technique to assess the impact of synaptic activity on neuronal protein trafficking and function. Current technology for neuronal stimulation in culture include chemical techniques or microelectrode or optogenetic based techniques. While technically powerful, chemical stimulation has limited spatial resolution and microelectrode and optogenetic techniques require specialized equipment and expertise. We report an optimized and improved technique for laser based photoconductive stimulation of live neurons using an inverted confocal microscope that overcomes these limitations. The advantages of this approach include its non-invasive nature and adaptability to temporal and spatial manipulation. We demonstrate that the technique can be manipulated to achieve spatially selective stimulation of live neurons. Coupled with live imaging of fluorescent indicators, this simple and efficient technique should allow for significant advances in neuronal cell biology.
Variability in PET quantitation within a multicenter consortium (2010)

Based on this investigation, a SUV variability in the range of 10%-25% due solely to instrument and analysis factors can be expected in the context of a multicenter consortium if a central reading is used and quality assurance and quality control procedures are followed. The overall SUV variability can be expected to be larger than this due to biological and protocol factors.
Three regimes of high-voltage breakdown in helium (2018)

A quasi-analytical model has been developed to map out the low-pressure (left-hand) branch of the Paschen curve at very high voltage when electrons are in the runaway regime and charge exchange/ionization avalanche by ions and fast neutral atoms becomes important. The model has been applied to helium gas between parallel-plate electrodes, at potentials ranging in magnitude between 10 and 1000 kilovolt. The respective value of reduced electric field <em>E/n</em> varies in the range of 50-6000 kTd (1 kTd =10<sup>-18</sup>Vm<sup>2</sup>), with reduced density <em>nd</em> (where <em>n</em> is the gas density and d is the interelectrode distance) on the order of 10<sup>20</sup>m<sup>-2</sup> . The analytical Paschen curve is compared to those obtained with a detailed Particle-In-Cell/Monte Carlo (PIC/MCC) simulation, and also to experimental measurements. The model provides accurate predictions for <em>E/n</em> up to ~10<sup>3</sup> kTd , constrained by availability and quality of required input data.
Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans (2011)

In general, dual scan based methods that use the lowest tube voltage available, have a higher CNR than the dual energy based approaches at the same dose level. Tin filtration improves the ability to differentiate between iodine and bone for the dual energy based masking method. In clinical practice, the advantages of the dual energy masking method might outweigh its disadvantage of a slightly higher dose penalty compared to the conventional dual scan masking method.
Supplementary Figure Legends 1-6 from Heterogeneous Nuclear Ribonucleoprotein H Blocks MST2-Mediated Apoptosis in Cancer Cells by Regulating <i>a-raf</i> Transcription (2023)

Supplementary Figure Legends 1-6 from Heterogeneous Nuclear Ribonucleoprotein H Blocks MST2-Mediated Apoptosis in Cancer Cells by Regulating &lt;i&gt;a-raf&lt;/i&gt; Transcription
A Minimal Model for G Protein–Mediated Synaptic Facilitation and Depression (2003)

G protein-coupled receptors are ubiquitous in neurons, as well as other cell types. Activation of receptors by hormones or neurotransmitters splits the G protein heterotrimer into Galpha and Gbetagamma subunits. It is now clear that Gbetagamma directly inhibits Ca2+ channels, putting them into a reluctant state. The effects of Gbetagamma depend on the specific beta and gamma subunits present, as well as the beta subunit isoform of the N-type Ca2+ channel. We describe a minimal mathematical model for the effects of G protein action on the dynamics of synaptic transmission. The model is calibrated by data obtained by transfecting G protein and Ca2+ channel subunits into tsA-201 cells. We demonstrate with numerical simulations that G protein action can provide a mechanism for either short-term synaptic facilitation or depression, depending on the manner in which G protein-coupled receptors are activated. The G protein action performs high-pass filtering of the presynaptic signal, with a filter cutoff that depends on the combination of G protein and Ca2+ channel subunits present. At stimulus frequencies above the cutoff, trains of single spikes are transmitted, while only doublets are transmitted at frequencies below the cutoff. Finally, we demonstrate that relief of G protein inhibition can contribute to paired-pulse facilitation.
Deadbeat-direct torque and flux control on low switching frequency induction machine drives using the enhanced flux observer and torque model (2013)

This paper presents a digital implementation of deadbeat-direct torque and flux control (DB-DTFC) for induction machines at low switching frequencies. For high switching frequencies, existing discrete time flux observers and Volt-sec.-based inverse torque models used for DB-DTFC achieve acceptable flux estimation accuracy and fast torque response. However, the flux estimate is less accurate when switching frequency is reduced and DB-DTFC performance degrades. This paper develops a more suitable flux observer and Volt-sec.-based inverse torque model that minimizes flux estimation error and improves torque control for DB-DTFC. Simulation and experimental results are provided to evaluate the performance of the proposed observer and torque model at very low switching frequencies. Consequently, digital implementation of low switching frequency DB-DTFC on high power induction machines is feasible.
Phase transformations during high-speed heat treatment of the system “carbide (M23C6)/(α-Fe) matrix” (2017)

A brief thermodynamic analysis of phase transformations taking place during heat treatment of the system Fe-Cr-C, which is the basis of high-chromium steel, is performed. It is shown that formation of both, solid solutions based on α-iron (BCC crystalline lattice) and γ-iron (FCC crystalline lattice) and an entire spectrum of carbide phases of the complex element composition (M23C6, M7C3, M3C and M3C2, where the symbol M stands for atoms of metallic elements Fe and Cr) is possible in this material under equilibrium conditions. The irradiation of steel with an intense pulsed electron beam is carried out. It is shown that electron-beam treatment of steel in the melting mode and the subsequent high-speed crystallization is accompanied by transformation of the surface layer structure, consisting of (1) the dissolution of particles of the initial carbide phase; (2) formation of dendritic crystallization cells of submicron (80…200 nm) sizes; (3) the repeated isolation of nanosized (10-15 nm) particles of the carbide phase.
Charge-based Delivery of Molecules to Skin Using Atmospheric Plasmas (2013)

We report the design, development and characterization of new atmospheric plasma-based protocols currently being examined in vivo using small animal models. Previously developed electric field mediated drug and gene delivery protocols use a pulsed DC voltage applied between electrodes on or in tissue to generate the required electric field to induce delivery of molecules. Plasma sources deliver roughly a million times less charge to skin compared with direct electrode-driven delivery methods, yet the efficiency of the process is dramatically similar with respect to the introduction of molecules to skin cells.
Review of dietary supplements for the management of osteoarthritis in dogs in studies from 2004 to 2014 (2015)

Osteoarthritis (OA) is a chronic, painful, degenerative and inflammatory disease that affects the synovial joints and leads finally to the loss of mobility. It is highly prevalent in dogs. Nowadays, no cure exists, and the pharmacological treatment is limited to clinical signs alleviation. Some positive beneficial effects have been highlighted with dietary supplements in the course of dog OA. The goals of this narrative review are to summarize the scientific data available in the literature on dietary supplements assessed in dog OA and to discuss some trails about how to improve several aspects of research and issues with dietary supplements, such as bioavailability and dosage regimen. Chondroitin sulphate, glucosamine, undenaturated type II collagen, avocado-soya bean unsaponifiables, curcumin and polyunsaturated fatty acids were studied in dog OA and therefore discussed in the present review. Most of them showed anticatabolic and anti-inflammatory effects. Unfortunately, few data exist concerning their pharmacokinetics. Their bioavailability is low, but new formulations are developed to enhance their gastrointestinal absorption. The clinical relevance of these new formulations compared to native forms should be demonstrated in good clinical trials. Even if further investigations are needed, dietary supplements should be considered in OA management.
A chemical basis for recognition of nonpeptide antigens by human γδ T cells* (2000)

Whereas αβ T cell receptors (TCR) recognize processed antigenic peptides or glycolipids bound respectively to major histocompatibility complex or CD1 molecules, γδ TCR react differently to a broad set of native antigens. A major human γδ T cell subset is activated through a mechanism involving Vγ 9Vδ 2 TCR and structurally unrelated phosphorylated nonpeptide antigens (referred to as phosphoantigens). Here, the structure‐function relationship of the strongest natural and synthetic phosphoantigens stimulating γδ cells was analyzed to elucidate the molecular basis of this unconventional recognition. Besides conformational determinants, we found that chemical reactivity of antigens is critical to their bioactivity. For Vγ 9Vδ 2 T cell activation, both organic and phosphorylated moieties of strong ligands undergo rapid and degradative structural changes. Conversely, analogs that are resistant to degradation specifically antagonize phosphoantigen‐mediated γδ T cell activation. These data suggest a novel mode of antigen perception involving both topological recognition and ligand consumption, which confers highly specific γδ T cell activation by structurally diverse ligands.
Assessment of the Quality of Frozen Serum by Spectrophotometric Analysis and Sperm Bioassay (1997)

Serum is an integral part of media used for in vitro fertilization (IVF) and andrology work. Previous studies showed that the IVF results could benefit if sera were screened for deleterious effects before use. Such screening is impractical when fresh sera are used but may be feasible if the serum is frozen prior to use. This study assessed the impact of freezing on the quality of serum. A total of 158 serum samples, prepared in a university-based andrology-IVF center, were included in the study. The frozen sera were thawed in batches to be used in a series of laboratory experiments. Serum quality was evaluated by spectrophotometric analysis and sperm bioassay under several defined conditions: fresh, frozen, pre- and postfiltration, pre- and postcentrifugation, and the patients' fertility condition. Although all sera were filtered through 0.22-micron filter, more than 10% frozen sera required 0.4- or a combination of 0.8- and 0.4-micron filters before they could be passed through the 0.22-micron filter. Frozen sera that were directly filtrable with a 0.22-micron filter lost 13% turbidity upon filtration. The turbidity of the frozen sera were higher compared to fresh ones as revealed by optical density (OD) and relative light scattering (RLS) spectrophotometry. The freeze/storage-induced spectrophotometric changes did not correlate with the storage time. The centrifugation caused precipitation of sera components. The rate of precipitation of the serum components correlated with the duration of freezing. Spectrophotometric analysis and sperm bioassay did not differentiate the sera of pregnancy-positive and pregnancy-negative subjects. The sperm bioassay failed to detect any biological impact of freezing-induced spectrophotometric changes in the sera, suggesting that the freezing-induced changes did not significantly diminish the serum's capability of supplementing the culture media.
Other Organs (2007)

This chapter contains sections titled: Introduction 3D imaging of embryos and mouse organs by Optical Projection Tomography Visualizing early Xenopus development with time lapse microscopic MRI Ultrasonic quantification of red blood cells development in mice Placental perfusion MR imaging with contrast agent in a mouse model Characterization of nephropathies and monitoring of renal stem cell therapies Optical imaging of lung inflammation Optical imaging in rheumatoid arthritis
Signaling and Functions of Angiopoietin-1 in Vascular Protection (2006)

Angiopoietin-1 (Ang1) has powerful vascular protective effects: suppressing plasma leakage, inhibiting vascular inflammation, and preventing endothelial death. Preclinical studies indicate that Ang1 may be therapeutically useful in a number of situations, including treatment of edema, endotoxemia, and transplant arteriosclerosis. However, the ligand has also been implicated in vessel remodeling, induction of angiogenesis and pulmonary hypertension, indicating that strategies to minimize any deleterious effects while optimizing vessel protection are likely to be needed. This review surveys the published data on vascular protective effects of Ang1 and highlights the therapeutic potential of this ligand, as well as possible limitations to its use. We also consider the data on Ang1 receptors and speculate on how to maximize therapeutic benefit by targeting the Tie receptors.
Overview of recent advances in passive millimeter-wave imaging in the UK (1996)

Passive millimeter wave (MMW) imaging systems have attracted an increasing interest over the past years due to their superior poor weather performance compared with visible and infrared (IR) systems. In the UK the Defence Research Agency Malvern developed its first MMW radiometers in the late 1950s. These systems were bulky and had poor spatial resolution and low thermal sensitivity, but the considerable advances in semiconductor solid state devices have allowed the size and weight of images to be reduced. Advantage can also be taken of sophisticated on-line signal processing and of complex theoretical modeling and analysis. This paper examines the impact of these advances of technology and to identify new methods to overcome the usual difficulties of poor spatial resolution and slow response time. High quality images are presented to demonstrate the potential of this emerging technology.