2,251 research outputs found
Investors' reactions to management earnings guidance: The joint effect of investment position, news valence, and guidance form
We report the results of an experiment that shows that investors' earnings- and investment-related judgments are jointly influenced by their investment position (long versus short), the news valence of guidance issued by management, and the amount of ambiguity in the guidance. Prior research indicates that guidance form (point versus range) has no effect on investors' earnings estimates made in reaction to management guidance. We extend this research by showing that guidance form matters, conditional on investment position and news valence. Similarly, prior research indicates that investors who hold long (short) positions in a stock are more optimistic (pessimistic) about the company's prospects. We extend this research by showing that the effect of investment position documented in prior studies is conditional on news valence and guidance form. We contribute to prior literature on the effects of investment position and guidance form by delineating boundary conditions for each of these effects. © 2009 University of Chicago on behalf of the Accounting Research Center.postprin
Fabrication of a Micro-Needle Sensor Based on Copper Microspheres and Polyaniline Film for Nitrate Determination in Coastal River Waters
In this work, a new micro-needle sensor based on copper microspheres (CuMSs) and polyaniline (PANI) film was fabricated through electrodeposition method and used for the voltammetric determination of nitrate (NO3-) in coastal river samples. The PANI film functions as the conductive polymer and adhesion agent to immobilize the CuMSs which has good electrocatalytic property for the reduction of NO3-. The CuMSs could be more easily deposited on the micro-needle electrode (MNE) surface with PANI film as adhesion agent. The physical and electrochemical properties of the as-prepared micro-needle electrode were characterized by different techniques. CuMSs with diameter of about 0.5 to 1 mu m were decorated on the PANI film modified micro-needle electrode. The unique structure of micro-needle electrode and excellent properties of CuMSs and PANI film make the micro-needle sensor possesses the advantages of larger specific surface and high electrocatalytic property towards the reduction of NO3-. The micro-needle electrode based on CuMSs and PANI film shows a linear response to NO3- in the concentrations ranging from 0.02 to 6 mM (R-2 = 0.995) with the detection limit of 8 mu M. More importantly, the determination of NO3- in coastal river water samples was achieved with the micro-needle electrode with satisfactory results. (C) The Author(s) 2019. Published by ECS
Ferromagnetic-organic interfacial states and their role on low voltage current injection in tris-8-hydroxyquinloline (Alq(3)) organic spin valves
Effect of Concentrated Fibroblast-Conditioned Media on In Vitro Maintenance of Rat Primary Hepatocyte
The effects of concentrated fibroblast-conditioned media were tested to determine whether hepatocyte function can be maintained without direct contact between hepatocytes and fibroblasts. Primary rat hepatocytes cultured with a concentrated conditioned media of NIH-3T3 J2 cell line (final concentration of 55 mg/ml) showed significantly improved survival and functions (albumin and urea) compared to those of control groups. They also showed higher expression levels of mRNA, albumin and tyrosine aminotransferase compared to hepatocyte monoculture. The results suggest that culture with concentrated fibroblast-conditioned media could be an easy method for in vitro maintenance of primary hepatocytes. They also could be contribute to understand and analyze co-culture condition of hepatocyte with stroma cells.1132Ysciescopu
Terahertz metamaterials on flexible polypropylene substrate
The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-014-9724-1In this work, we present a metamaterial working at terahertz frequencies made over a flexible polypropylene sub-strate. The experimental measurements, in accordance with the numerical calculations, show the metamaterial reliance on the impinging electric field polarization. The structure s symmetry yields purely electrical resonant responses eliminating bianisotropy effects. The widely used bendable polypropylene polymer may promote the insertion of metamaterial-based structures with special electromagnetic response in a number of objects of our daily lives such as textiles, automotive components, and sensingThis work was supported by the Spanish MICINN under contracts CONSOLIDER EMET CSD2008-00066 and TEC2011-28664-C02-02 and by the Universitat Politecnica de Valencia under the program INNOVA 2011.Ortuño Molinero, R.; García Meca, C.; Martínez Abietar, AJ. (2014). Terahertz metamaterials on flexible polypropylene substrate. Plasmonics. 9(5):1143-1147. https://doi.org/10.1007/s11468-014-9724-1S1143114795Smith DR, Padilla WJ, Vier DC, Nemat-Nasser SC, Schultz S (2000) Composite medium with simultaneously negative permeability and permittivity. Phys Rev Lett 84:4184–4187Pendry JB (2000) Negative refraction makes a perfect lens. Phys Rev Lett 85:3966–3969Zhang X, Liu Z (2008) Superlenses to overcome the diffraction limit. Nat Mater 7:435–441Pendry JB, Schurig D, Smith DR (2006) Controlling electromagnetic fields. Science 312:1780–1782Schurig D, Mock JJ, Justice BJ, Cummer SA, Pendry JB, Starr AF, Smith DR (2006) Metamaterial electromagnetic cloak at microwave frequencies. Science 314:977–980Rodríguez-Cantó PJ, Martínez-Marco M, Rodríguez-Fortuño FJ, Tomás-Navarro B, Ortuño R, Peransí-Llopis S, Martínez A (2011) Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon. Opt Express 19:7664–7672Rodríguez-Fortuño FJ, Martínez-Marco M, Tomás-Navarro B, Ortuño R, Martí J, Martínez A, Rodríguez-Cantó PJ (2011) Highly-sensitive chemical detection in the infrared regime using plasmonic gold nanocrosses. Appl Phys Lett 98:133118O’Hara FJ, Singh R, Brener I, Smirnova E, Han J, Taylor AJ, Zhang W (2008) Thin-film sensing with planar terahertz metamaterials: sensitivity and limitations. Opt Express 16:1786–1795Tao H, Landy NI, Bingham CM, Zhang X, Averitt RD, Padilla WJ (2008) A metamaterial absorber for the terahertz regime: design, fabrication and characterization. Opt Express 16:7181–7188Iwaszczuk K, Strikwerda AC, Fan K, Zhang X, Averitt RD, Jepsen PU (2012) Flexible metamaterial absorbers for stealth applications at terahertz frequencies. Opt Express 20:635–643Tao H, Bingham CM, Strikwerda AC, Pilon D, Shrekenhamer D, Landy NI, Fan K, Zhang X, Padilla WJ, Averitt RD (2008) Highly flexible wide angle of incidence terahertz metamaterial absorber: design, fabrication, and characterization. Phys Rev B 78:241103(R)Tao H, Bingham CM, Pilon D, Fan K, Strikwerda AC, Shrekenhamer D, Padilla WJ, Zhang X, Averitt RD (2010) A dual band terahertz metamaterial absorber. J Phys D: Appl Phys 43:225102Padilla WJ, Taylor AJ, Highstrete C, Lee M, Averitt RD (2006) Dynamical electric and magnetic metamaterial response at terahertz frequencies. Phys Rev Lett 96:107401Chen HT, Padilla WJ, Zide JMO, Gossard AC, Taylor AJ, Averitt RD (2006) Active terahertz metamaterial devices. Nature 444:597–600Chen HT, O’Hara FJ, Azad AK, Taylor AJ, Averitt RD, Shrekenhamer DB, Padilla WJ (2008) Experimental demonstration of frequency-agile terahertz metamaterials. Nature Photon 2:295–298Chen HT, Padilla WJ, Zide JMO, Bank SR, Gossard AC, Taylor AJ, Averitt RD (2007) Ultrafast optical switching of terahertz metamaterials fabricated on ErAs/GaAs nanoisland superlattices. Opt Lett 32:1620–1622Chen HT, Palit S, Tyler T, Bingham CM, Zide JMO, O’Hara FJ, Smith DR, Gossard AC, Averitt RD, Padilla WJ, Jokerst NM, Taylor AJ (2008) Hybrid metamaterials enable fast electrical modulation of freely propagating terahertz waves. Appl Phys Lett 93:091117Chen HT, Padilla WJ, Cich MJ, Azad AK, Averitt RD, Taylor AJ (2009) A metamaterial solid-state terahertz phase modulator. Nat Photon 3:148Driscoll T, Andreev GO, Basov DN, Palit S, Cho SY, Jokerst NM, Smith DR (2007) Tuned permeability in terahertz split-ring resonators for devices and sensors. Appl Phys Lett 91:062511Debus C, Bolivar PH (2007) Frequency selective surfaces for high sensitivity terahertz sensing. Appl Phys Lett 91:184102Al-Naib IAI, Jansen C, Koch M (2008) Thin-film sensing with planar asymmetric metamaterial resonators. Appl Phys Lett 93:083507Leonhardt U, Philbin TG (2010) Geometry and light: the science of invisibility. Dover, MineolaDi Falco A, Ploschner M, Krauss TF (2010) Flexible metamaterials at visible wavelengths. New J Phys 12:113006Tao H, Strikwerda AC, Fan K, Bingham CM, Padilla WJ, Zhang X, Averitt RD (2008) Terahertz metamaterials on free-standing highly-flexible polyimide substrates. Appl Phys 41:232004Tao H, Amsden JJ, Strikwerda AC, Fan K, Kaplan DL, Zhang X, Averitt RD, Omenetto FJ (2010) Metamaterial silk composites at terahertz frequencies. Adv Mater 22:3527–3531Chen ZC, Han NR, Pan ZY, Gong YD, Chong TC, Hong MH (2011) Tunable resonance enhancement of multi-layer terahertz metamaterials fabricated by parallel laser micro-lens array lithography on flexible substrates. 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Early mortality and overall survival in oncology phase I trial participants: can we improve patient selection?
<p>Abstract</p> <p>Background</p> <p>Patient selection for phase I trials (PIT) in oncology is challenging. A typical inclusion criterion for PIT is 'life expectancy > 3 months', however the 90 day mortality (90DM) and overall survival (OS) of patients with advanced solid malignancies are difficult to predict.</p> <p>Methods</p> <p>We analyzed 233 patients who were enrolled in PIT at Princess Margaret Hospital. We assessed the relationship between 17 clinical characteristics and 90DM using univariate and multivariate logistic regression analyses to create a risk score (PMHI). We also applied the Royal Marsden Hospital risk score (RMI), which consists of 3 markers (albumin < 35g/L, > 2 metastatic sites, LDH > ULN).</p> <p>Results</p> <p>Median age was 57 years (range 21-88). The 90DM rate was 14%; median OS was 320 days. Predictors of 90DM were albumin < 35g/L (OR = 8.2, p = 0.01), > 2 metastatic sites (OR = 2.6, p = 0.02), and ECOG > 0 (OR = 6.3, p = 0.001); all 3 factors constitute the PMHI. To predict 90DM, the PMHI performed better than the RMI (AUC = 0.78 vs 0.69). To predict OS, the RMI performed slightly better (RMI ≥ 2, HR = 2.2, p = 0.002 vs PMHI ≥ 2, HR = 1.6, p = 0.05).</p> <p>Conclusions</p> <p>To predict 90DM, the PMHI is helpful. To predict OS, risk models should include ECOG > 0, > 2 metastatic sites, and LDH > ULN. Prospective validation of the PMHI is warranted.</p
Preparation and thermal conductivity of CuO nanofluid via a wet chemical method
In this article, a wet chemical method was developed to prepare stable CuO nanofluids. The influences of synthesis parameters, such as kinds and amounts of copper salts, reaction time, were studied. The thermal conductivities of CuO nanofluids were also investigated. The results showed that different copper salts resulted in different particle morphology. The concentration of copper acetate and reaction time affected the size and shape of clusters of primary nanoparticles. Nanofluids with different microstructures could be obtained by changing the synthesis parameters. The thermal conductivities of CuO nanofluids increased with the increase of particle loading
In-situ Synthesis of Graphitic Carbon Nitride/Gold Nanoparticle Nanocomposites for Electrocatalytic Reduction of Iron(III)
The graphitic carbon nitride/gold nanoparticle (g-C3N4/AuNP) nanocomposites were reported in this paper based on an in-situ synthetic method. After the protonation, ion-exchange, and chemical reduction processes, the g-C3N4/AuNP nanocomposites were successfully obtained. The proposed nanocomposites were investigated by various optical and electrical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), etc. The g-C3N4/AuNP nanocomposites showed excellent electrochemical properties and their preliminary applications toward electrocatalytic reduction of ferric iron were investigated. These nanocomposites exhibit promising prospects for practical application in electrochemical analysis
Microtubules gate tau condensation to spatially regulate microtubule functions.
Tau is an abundant microtubule-associated protein in neurons. Tau aggregation into insoluble fibrils is a hallmark of Alzheimer's disease and other types of dementia1, yet the physiological state of tau molecules within cells remains unclear. Using single-molecule imaging, we directly observe that the microtubule lattice regulates reversible tau self-association, leading to localized, dynamic condensation of tau molecules on the microtubule surface. Tau condensates form selectively permissible barriers, spatially regulating the activity of microtubule-severing enzymes and the movement of molecular motors through their boundaries. We propose that reversible self-association of tau molecules, gated by the microtubule lattice, is an important mechanism of the biological functions of tau, and that oligomerization of tau is a common property shared between the physiological and disease-associated forms of the molecule
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