106 research outputs found

    Monolithic Metamaterial-Integrated Graphene Terahertz Photodetector with Wavelength and Polarization Selectivity

    No full text
    The frequency spectra and polarization states of terahertz waves can convey significant information about physical interactions and material properties. Compact and miniaturized on-chip platforms for effective capturing of these quantities are being extensively investigated because of their promising potential for paramount applications of terahertz technology such as in situ sensing and characterization. Here, we present a metamaterial–graphene hybrid device that integrates the functions of photodetection, wavelength, and polarization selectivity into a monolithic architecture. Leveraging the ultrahigh design freedom of metamaterial optical properties and the electronically controllable hot-carrier-assisted photothermoelectric effect in graphene, our detector shows resonantly enhanced photoresponse at two specific target wavelengths with orthogonal polarizations. We demonstrate its versatile capabilities for spectrally selective and polarization resolved imaging on a single-chip platform that is free from advanced optical components. Our strategy is beneficial to the future development of multifunctional, compact, and low-cost terahertz sensors

    Extraperitoneal versus transperitoneal cesarean section: a retrospective study

    No full text
    To evaluate extraperitoneal cesarean section as a routine elective surgery. In this retrospective study, 461 primiparas were divided into the extraperitoneal and transperitoneal cesarean section groups according to the operation type in a random, but non-blinded, manner. The outcome measures were intraoperative blood loss, operation duration, postoperative gas passage time, postoperative pain, postoperative complications, and neonatal indicators The operation duration of the extraperitoneal cesarean section group was significantly lower than that of the transperitoneal cesarean section group (P  While extraperitoneal cesarean section can be safely performed as a routine procedure in the surgical delivery of primiparas, it must be performed by well-trained surgeons. In view of its advantages, it is worth being promoted in senior general hospitals as a routine choice. Abbreviations: CS: Cesarean section; ECS: Extraperitoneal; TCS: Transperitoneal; VAS: Visual analogue scale.</p

    Templateless Infrared Heating Process for Fabricating Carbon Nitride Nanorods with Efficient Photocatalytic H<sub>2</sub> Evolution

    No full text
    The bottom-up fabrication of carbon nitride nanorods is realized through the direct infrared heating of dicyandiamide. The approach requires no templates or extra organics. The controlled infrared heating has a major influence on the morphology of the obtained carbon nitrides. The precursors assemble into carbon nitride nanorods at low power levels, and they grow into nanoplates at high power levels. The formation mechanism of the carbon nitride nanorods is proposed to be a kinetically driven process, and the photocatalytic activity of the carbon nitride nanorods prepared at 50% power for hydrogen evolution is about 2.9 times that of carbon nitride nanoplates at 100% power. Structural, optical, and electronic analysis demonstrates that the enhancement is primarily attributed to the elimination of structural defects and the improved charge-carrier separation in highly condensed and oriented carbon nitride nanorods

    sj-docx-1-heb-10.1177_10901981231158412 – Supplemental material for Persuasive Narratives About Osteoporosis: Effects of Protagonist Competence, Narrator Point of View, and Subjective Risk

    No full text
    Supplemental material, sj-docx-1-heb-10.1177_10901981231158412 for Persuasive Narratives About Osteoporosis: Effects of Protagonist Competence, Narrator Point of View, and Subjective Risk by Meng Chen, Laramie D. Taylor and Robert A. Bell in Health Education & Behavior</p

    Pd(II)-Mediated Triad Multilayers with Zinc Tetrapyridylporphyrin and Pyridine-Functionalized Nano-TiO<sub>2</sub> as Linkers: Assembly, Characterization, and Photocatalytic Properties

    No full text
    Triad hybrid multilayers containing the light sensitizers of zinc tetrapyridylporphyrin (ZnTPyP) and pyridine-functionalized TiO<sub>2</sub> (TiO<sub>2</sub>-Py) nanoparticles were constructed on substrate surfaces with the use of Pd­(II) ions as the connectors using the layer-by-layer (LBL) method. The assembly process was monitored using ultraviolet–visible (UV–vis) absorption and X-ray photoelectron spectra as well as scanning electron microscopy and atomic force microscopy. The content of the pyridine substituents in the TiO<sub>2</sub>-Py nanocomposites was about 2% (w/w). The Soret absorption band of ZnTPyP was 24 nm red-shifted in the hybrid multilayers due to a strong intermolecular electronic coupling interaction among porphyrin macrocycles or porphyrin macrocycle/TiO<sub>2</sub>-Py nanoparticles. The average surface density of each ZnTPyP layer was about 1.4 × 10<sup>–10</sup> mol/cm<sup>2</sup>. Aggregation of the small TiO<sub>2</sub>-Py nanoparticles to larger domains with sizes up to hundreds of nanometers occurred in the hybrid multilayers; however, such an aggregation behavior was weaker than that in the solutions. The quartz substrate modified with the as-prepared Pd/ZnTPyP/Pd/TiO<sub>2</sub>-Py triad hybrid multilayers was used as a heterogeneous photocatalyst for the degradation of methyl orange (MO) under irradiation (λ > 420 nm) at room temperature with a catalytic efficiency of about 1.3 × 10<sup>–3</sup> MO/ZnTPyP·s. Without the use of the filter, the catalytic efficiency increased because both ZnTPyP and TiO<sub>2</sub>-Py nanocomposites acted as the light sensitizers. It is suggested that the present heterogeneous catalyst has the advantages of facile separation, high stability, structural controllability on the molecular and nanoscale level, and good recyclability

    Identification of eligible studies.

    No full text
    <p>Identification of eligible studies.</p

    A Simple and Fast Extraction Method for the Determination of Multiclass Antibiotics in Eggs Using LC-MS/MS

    No full text
    The purpose of this study was to develop and validate a simple, fast, and specific extraction method for the analysis of 64 antibiotics from nine classes (including sulfonamides, quinolones, tetracyclines, macrolides, lincosamide, nitrofurans, β-lactams, nitromidazoles, and cloramphenicols) in chicken eggs. Briefly, egg samples were simply extracted with a mixture of acetonitrile–water (90:10, v/v) and 0.1 mol·L<sup>–1</sup> Na<sub>2</sub>EDTA solution assisted with ultrasonic. The extract was centrifuged, condensed, and directly analyzed on a liquid chromatography coupled to tandem mass spectrometry. Compared with conventional cleanup methods (passing through solid phase extract cartridges), the established method demonstrated comparable efficiencies in eliminating matrix effects and higher or equivalent recoveries for most of the target compounds. Typical validation parameters including specificity, linearity, matrix effect, limits of detection (LODs) and quantification (LOQs), the decision limit, detection capability, trueness, and precision were evaluated. The recoveries of target compounds ranged from 70.8% to 116.1% at three spiking levels (5, 20, and 50 μg·kg<sup>–1</sup>), with relative standard deviations less than 14%. LODs and LOQs were in the ranges of 0.005–2.00 μg·kg<sup>–1</sup> and 0.015–6.00 μg·kg<sup>–1</sup> for all of the antibiotics, respectively. A total of five antibiotics were successfully detected in 22 commercial eggs from local markets. This work suggests that the method is suitable for the analysis of multiclass antibiotics in eggs

    Forest plot showing adverse effects of antidepressants versus placebo.

    No full text
    <p>Antidepressants significantly increase adverse events compared with placebo.</p

    Noise Attenuation in the ON and OFF States of Biological Switches

    No full text
    Biological switches must sense changes in signal concentration and at the same time buffer against signal noise. While many studies have focused on the response of switching systems to noise in the ON state, how systems buffer noise at both ON and OFF states is poorly understood. Through analytical and computational approaches, we find that switching systems require different dynamics at the OFF state than at the ON state in order to have good noise buffering capability. Specifically, we introduce a quantity called the input-associated Signed Activation Time (iSAT) that concisely captures an intrinsic temporal property at either the ON or OFF state. We discover a trade-off between achieving good noise buffering in the ON versus the OFF states: a large iSAT corresponds to noise amplification in the OFF state in contrast to noise buffering in the ON state. To search for biological circuits that can buffer noise in both ON and OFF states, we systematically analyze all three-node circuits and identify mutual activation as a central motif. We also study connections among signal sensitivity, iSAT, and noise amplification. We find that a large iSAT at the ON state maintains signaling sensitivity while minimizing noise propagation. Taken together, the analysis of iSATs helps reveal the noise properties of biological networks and should aid in the design of robust switches that can both repress noise at the OFF state and maintain a reliable ON state
    • …
    corecore