4,140 research outputs found

    Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives

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    Spin-coating has been used extensively in the fabrication of electronic devices; however, the effects of the processing parameters have not been fully explored. Here, we systematically characterize the effects of the spin-coating time on the microstructure evolution during semiconducting polymer solidification in an effort to establish the relationship between this parameter and the performances of the resulting polymer field-effect transistors (FETs). We found that a short spin-coating time of a few seconds dramatically improve the morphology and molecular order in a conjugated polymer thin film because the p-p stacking structures formed by the polymer molecules grow slowly and with a greater degree of order due to the residual solvent present in the wet film. The improved ordering is correlated with improved charge carrier transport in the FETs prepared from these films. We also demonstrated the effects of various processing additives on the resulting FET characteristics as well as on the film drying behavior during spin-coating. The physical properties of the additives are found to affect the film drying process and the resulting device performance.113427Ysciescopu

    Adsorption-induced conversion of the carbon nanotube field effect transistor from ambipolar to unipolar behavior

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    We investigate ambipolar to unipolar transition by the effect of ambient air on the carbon nanotube field-effect transistor. A unipolar transport property of the double-walled nanotube field-effect transistor and its conversion from ambipolar behavior are observed. We suggest that adsorptions of oxygen molecules, whose lowest-unoccupied-molecular-orbital state is around the midgap of the carbon nanotube, could suppress the electron channel formation and, consequently, result in the unipolar transport behavior.open343

    Growth, Reproductive Condition, And Digestive Tubule Atrophy Of Pacific Oyster Crassostrea Gigas In Gamakman Bay Off The Southern Coast Of Korea

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    Spat of Pacific oysters (Crassostrea gigas) were collected from Gamakman Bay, Korea, and raised in a spat hardening facility located in the low intertidal zone of the bay for a hardening/stunting period of 10 mo. Seasonal changes in growth, reproductive condition, and digestive tubule atrophy (DTA) of these hardened/stunted oysters were monitored for more than a year after transplanting to a suspended longline system in a grow-out area in the bay. After transplantation, the hardened/stunted oysters showed a logarithmic increase in shell size for the first 4 mo, from June to October, and growth remained stable from late fall to early spring. During the 12 mo of the grow-out, the shell size of the hardened/stunted oysters increased from 15.4-74.2 mm, and tissue weight increased from 0.49-12.85 g. Histological analysis revealed that gametogenesis of hardened/stunted oysters commenced as early as February when water temperature remained at 10 degrees C, and spawning occurred from July to September when water temperature reached 25-27 degrees C. DTA assessed from histological analysis was higher from September to February, when the chlorophyll a level in the bay was lower. These data suggest that seasonal fluctuations in water temperature and food availability in the water column are the 2 main environmental parameters governing reproduction and growth of oyster in Gamakman Bay, and DTA could be a useful biomarker for monitoring the nutritional condition of oysters

    Vascular Proteomics Reveal Novel Proteins Involved in SMC Phenotypic Change: OLR1 as a SMC Receptor Regulating Proliferation and Inflammatory Response

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    Neointimal hyperplasia of vascular smooth muscle cells (VSMC) plays a critical role in atherosclerotic plaque formation and in-stent restenosis, but the underlying mechanisms are still incompletely understood. We performed a proteomics study to identify novel signaling molecules organizing the VSMC hyperplasia. The differential proteomics analysis in a balloon- induced injury model of rat carotid artery revealed that the expressions of 44 proteins are changed within 3 days post injury. The combination of cellular function assays and a protein network analysis further demonstrated that 27 out of 44 proteins constitute key signaling networks orchestrating the phenotypic change of VSMC from contractile to epithelial-like synthetic. Among the list of proteins, the in vivo validation specifically revealed that six proteins (Rab 15, ITR, OLR1, PDH beta, PTP epsilon) are positive regulators for VSMC hyperplasia. In particular, the OLR1 played dual roles in the VSMC hyperplasia by directly mediating oxidized LDL-induced monocyte adhesion via NF-kappa B activation and by assisting the PDGF-induced proliferation/migration. Importantly, OLR1 and PDGFR beta were associated in close proximity in the plasma membrane. Thus, this study elicits the protein network organizing the phenotypic change of VSMC in the vascular injury diseases such as atherosclerosis and discovers OLR1 as a novel molecular link between the proliferative and inflammatory responses of VSMCs.1133Ysciescopu

    The immediate upstream region of the 5 '-UTR from the AUG start codon has a pronounced effect on the translational efficiency in Arabidopsis thaliana

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    The nucleotide sequence around the translational initiation site is an important cis-acting element for post-transcriptional regulation. However, it has not been fully understood how the sequence context at the 5'-untranslated region (5'-UTR) affects the translational efficiency of individual mRNAs. In this study, we provide evidence that the 5'-UTRs of Arabidopsis genes showing a great difference in the nucleotide sequence vary greatly in translational efficiency with more than a 200-fold difference. Of the four types of nucleotides, the A residue was the most favourable nucleotide from positions -1 to -21 of the 5'-UTRs in Arabidopsis genes. In particular, the A residue in the 5'-UTR from positions -1 to -5 was required for a high-level translational efficiency. In contrast, the T residue in the 5'-UTR from positions -1 to -5 was the least favourable nucleotide in translational efficiency. Furthermore, the effect of the sequence context in the -1 to -21 region of the 5'-UTR was conserved in different plant species. Based on these observations, we propose that the sequence context immediately upstream of the AUG initiation codon plays a crucial role in determining the translational efficiency of plant genes.ope

    Intravaginal Administration of Fc-Fused IL7 Suppresses the Cervicovaginal Tumor by Recruiting HPV DNA Vaccine-Induced CD8 T Cells

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    Purpose: The induction of tissue-localized virus-specific CD8 T-cell response is essential for the development of an effective therapeutic vaccine against genital diseases, such as cervical cancer and genital herpes. Here, we aimed to elucidate the immunologic role of IL7 in the induction of mucosal cellular immunity. Experimental Design: IL7 was engineered through Fc fusion to enhance mucosal delivery across the genital epithelial barrier. The immunomodulatory role of IL7 was evaluated by monitoring the kinetics of various immune cells and measuring the expression of chemokines and cytokines after intravaginal administration of Fc-fused IL7 (IL7-Fc). The antitumor effects of intramuscular human papillomavirus (HPV) DNA vaccine or topical IL7-Fc alone or in a combinational regimen on mice survival were compared using a orthotopic cervical cancer model. Results: Intravaginal treatment of IL7-Fc, but not native IL7, induces upregulation of chemokines (CXCL10, CCL3, CCL4, and CCL5), cytokines (IFN-gamma, TNF alpha, IL6, and IL1 beta), and an adhesion molecule (VCAM-1) in the genital tract, leading to the recruitment of several leukocytes, including CD4, CD8, gamma delta T cells, and dendritic cells. Importantly, in this murine cervical cancer model, topical administration of IL7-Fc after intramuscular HPV DNA vaccination increases the number of HPV-specific CD8 T cells in the genital mucosa, but not in the spleen, leading to stronger antitumor activity than the HPV DNA vaccine alone. Conclusions: Our findings provide an important insight into the immunomodulatory role of IL7-Fc via topical application and the design of therapeutic vaccine regimen that induces effective genital-mucosal CD8 T-cell responses.1110Ysciescopu

    Diseleno[3,2-b:2′,3′-d]selenophene-containing high-mobility conjugated polymer for organic field-effect transistors

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    KGaA, Weinheim The synthesis of a diseleno[3,2-b:2′,3′-d]selenophene (DSS) composed of three fused selenophenes is reported and it is used as a building block for the preparation of a high hole mobility conjugated polymer (PDSSTV). The polymer demonstrates strong intermolecular interactions even in solution, despite steric repulsion between the large Se atom in DSS and adjacent (C β )–H atoms which leads to a partially twisted confirmation PDSSTV. Nevertheless, 2D grazing incidence X-ray diffraction (2D-GIXD) analysis reveals that the polymer tends to align in a highly ordered edge-on orientation after thermal annealing. The polymer demonstrates promising performance in a field-effect transistor device with saturated hole mobility up to 2 cm 2 V −1 s −1 obtained under relatively low gate voltages of −30 V. The ultilization of a Se-containing fused aromatic system, therefore, appears to be a promising avenue for the development of high-performance conjugated polymers

    Synergistic effect of intrathecal fentanyl and bupivacaine in spinal anesthesia for cesarean section

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    BACKGROUND: Potentiating the effect of intrathecal local anesthetics by addition of intrathecal opiods for intra-abdominal surgeries is known. In this study by addition of fentanyl we tried to minimize the dose of bupivacaine, thereby reducing the side effects caused by higher doses of intrathecal bupivacaine in cesarean section. METHODS: Study was performed on 120 cesarean section parturients divided into six groups, identified as B(8), B(10 )and B (12.5 )8.10 and 12.5 mg of bupivacaine mg and FB(8), FB(10 )and FB (12.5 )received a combination of 12.5 μg intrathecal fentanyl respectively. The parameters taken into consideration were visceral pain, hemodynamic stability, intraoperative sedation, intraoperative and postoperative shivering, and postoperative pain. RESULTS: Onset of sensory block to T6 occurred faster with increasing bupivacaine doses in bupivacaine only groups and bupivacaine -fentanyl combination groups. Alone lower concentrations of bupivacaine could not complete removed the visceral pain. Blood pressure declined with the increasing concentration of Bupivacaine and Fentanyl. Incidence of nausea and shivering reduces significantly whereas, the postoperative pain relief and hemodynamics increased by adding fentanyl. Pruritis, maternal respiratory depression and changes in Apgar score of babies do not occur with fentanyl. CONCLUSION: Spinal anesthesia among the neuraxial blocks in obstetric patients needs strict dose calculations because minimal dose changes, complications and side effects arise, providing impetus for this study. Here the synergistic, potentiating effect of fentanyl (an opiod) on bupivacaine (a local anesthetic) in spinal anesthesia for cesarian section is presented, fentanyl is able to reduce the dose of bupivacaine and therefore its harmful effects

    A Robust Peak-to-Average Power Ratio Reduction Scheme by Inserting Dummy Signals with Enhanced Partial Transmit Sequence in OFDM Systems.

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    Peak-to-average power ratio (PAPR) is one of the main drawbacks in orthogonal frequency division multiplexing (OFDM) systems. High PAPR forces the power amplifier to back off in order to operate in its linear region, which degrades the power efficiency of the system. Several PAPR reduction techniques have been developed, but most of them have not considered both complexity and PAPR reduction. In this paper, a novel PAPR reduction scheme based on the insertion of dummy sequences to an enhanced partial transmit sequence is proposed. By applying this scheme the PAPR performance is enhanced compared to the conventional methods while the complexity is significantly reduced. Numerical analysis is carried out with OFDM signal and QPSK modulation

    Spin-orbit coupled molecular quantum magnetism realized in inorganic solid

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    Molecular quantum magnetism involving an isolated spin state is of particular interest due to the characteristic quantum phenomena underlying spin qubits or molecular spintronics for quantum information devices, as demonstrated in magnetic metal-organic molecular systems, the so-called molecular magnets. Here we report the molecular quantum magnetism realized in an inorganic solid Ba3Yb2Zn5O11 with spin-orbit coupled pseudospin-1/2 Yb3+ ions. The magnetization represents the magnetic quantum values of an isolated Yb-4 tetrahedron with a total (pseudo) spin 0, 1 and 2. Inelastic neutron scattering results reveal that a large Dzyaloshinsky-Moriya interaction originating from strong spin-orbit coupling of Yb 4f is a key ingredient to explain magnetic excitations of the molecular magnet states. The Dzyaloshinsky-Moriya interaction allows a non-adiabatic quantum transition between avoided crossing energy levels, and also results in unexpected magnetic behaviours in conventional molecular magnets.1141Ysciescopu
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