101 research outputs found

    High-energy electronic excitations in Sr2_2IrO4_4 observed by Raman scattering

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    Spin-orbit interaction in Sr2_2IrO4_4 leads to the realization of the JeffJ_{\mathrm{eff}} = 1/2 state and also induces an insulating behavior. Using large-shift Raman spectroscopy, we found two high-energy excitations of the d-shell multipletat at 690 meV and 680 meV with A1gA_{1g} and B1gB_{1g} symmetry respectively. As temperature decreases, the A1gA_{1g} and B1gB_{1g} peaks narrow, and the A1gA_{1g} peak shifts to higher energy while the energy of the B1gB_{1g} peak remains the same. When 25%\% of Ir is substituted with Rh the A1gA_{1g} peak softens by 10%\% but the B1gB_{1g} peak does not. We show that both pseudospin-flip and non-pseudosin-flip dd electronic transitions are Raman active, but only the latter are observed

    k-Same-Siamese-GAN: k-Same Algorithm with Generative Adversarial Network for Facial Image De-identification with Hyperparameter Tuning and Mixed Precision Training

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    For a data holder, such as a hospital or a government entity, who has a privately held collection of personal data, in which the revealing and/or processing of the personal identifiable data is restricted and prohibited by law. Then, "how can we ensure the data holder does conceal the identity of each individual in the imagery of personal data while still preserving certain useful aspects of the data after de-identification?" becomes a challenge issue. In this work, we propose an approach towards high-resolution facial image de-identification, called k-Same-Siamese-GAN, which leverages the k-Same-Anonymity mechanism, the Generative Adversarial Network, and the hyperparameter tuning methods. Moreover, to speed up model training and reduce memory consumption, the mixed precision training technique is also applied to make kSS-GAN provide guarantees regarding privacy protection on close-form identities and be trained much more efficiently as well. Finally, to validate its applicability, the proposed work has been applied to actual datasets - RafD and CelebA for performance testing. Besides protecting privacy of high-resolution facial images, the proposed system is also justified for its ability in automating parameter tuning and breaking through the limitation of the number of adjustable parameters

    High-Energy Electronic Excitations in Sr\u3csub\u3e2\u3c/sub\u3eIrO\u3csub\u3e4\u3c/sub\u3e Observed by Raman Scattering

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    Spin-orbit interaction in Sr2IrO4 leads to the realization of the Jeff=1/2 state and also induces an insulating behavior. Using large-shift Raman spectroscopy, we found two high-energy excitations of the d-shell multiplet at 690 and 680 meV with A1g and B1g symmetry, respectively. As temperature decreases, the A1g and B1g peaks narrow, and the A1g peak shifts to higher energy while the energy of the B1g peak remains the same. When 25% of Ir is substituted with Rh the A1g peak softens by 10% but the B1g peak does not. We show that both pseudospin-flip and non-pseudo-spin-flip d-d electronic transitions are Raman active, but only the latter are observed. Our experiments and analysis place significant new constraints on the possible electronic structure of Sr2IrO4

    6-Mercaptopurine attenuates tumor necrosis factor-α production in microglia through Nur77-mediated transrepression and PI3K/Akt/mTOR signaling-mediated translational regulation

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    Physical interaction between Nur77 and p65. BV-2 cells were pretreated with 6-MP (50 μM) for 16 h followed by exposure to LPS (100 ng/ml) for 60 min. Nuclear extracts were harvested for immunoprecipitation (IP) experiments using anti-Nur77 and anti-p65 antibodies. Immunoblot (IB) analyses of the immunoprecipitates were performed using these antibodies. The immunoblots are representative of three independent experiments. (TIF 280 kb

    Synthetic phosphoethanolamine-modified oligosaccharides reveal the importance of glycan length and substitution in biofilm-inspired assemblies

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    Bacterial biofilm matrices are nanocomposites of proteins and polysaccharides with remarkable mechanical properties. Efforts understanding and tuning the protein component have been extensive, whereas the polysaccharide part remained mostly overlooked. The discovery of phosphoethanolamine (pEtN) modified cellulose in E. coli biofilms revealed that polysaccharide functionalization alters the biofilm properties. To date, the pattern of pEtN cellulose and its mode of interactions with proteins remains elusive. Herein, we report a model system based on synthetic epitomes to explore the role of pEtN in biofilm-inspired assemblies. Nine pEtN-modified oligosaccharides were synthesized with full control over the length, degree and pattern of pEtN substitution. The oligomers were co-assembled with a representative peptide, triggering the formation of fibers in a length dependent manner. We discovered that the pEtN pattern modulates the adhesion of biofilm-inspired matrices, while the peptide component controls its stiffness. Unnatural oligosaccharides tune or disrupt the assembly morphology, revealing interesting targets for polysaccharide engineering to develop tunable bio-inspired materials

    Quantum coherence enhances electron transfer rates to two equivalent electron acceptors

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    When a molecular electron donor interacts with multiple electron acceptors, quantum coherence can enhance the electron transfer (ET) rate. Here we report photodriven ET rates in a pair of donor–acceptor (D-A) compounds that link one anthracene (An) donor to one or two equivalent 1,4-benzoquinone (BQ) acceptors. Subpicosecond ET from the lowest excited singlet state of An to two BQs is about 2.4 times faster than ET to one BQ at room temperature, but about 5 times faster at cryogenic temperatures. This factor of 2 increase results from a transition from ET to one of two acceptors at room temperature to ET to a superposition state of the two acceptors with correlated system–bath fluctuations at low temperature

    Estrogen Modulates the Sensitivity of Lung Vagal C Fibers in Female Rats Exposed to Intermittent Hypoxia

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    Obstructive sleep apnea is mainly characterized by intermittent hypoxia (IH), which is associated with hyperreactive airway diseases and lung inflammation. Sensitization of lung vagal C fibers (LVCFs) induced by inflammatory mediators may play a central role in the pathogenesis of airway hypersensitivity. In females, estrogen interferes with inflammatory signaling pathways that may modulate airway hyperreactivity. In this study, we investigated the effects of IH on the reflex and afferent responses of LVCFs to chemical stimulants and lung inflammation in adult female rats, as well as the role of estrogen in these responses. Intact and ovariectomized (OVX) female rats were exposed to room air (RA) or IH for 14 consecutive days. On day 15, IH enhanced apneic responses to right atrial injection of chemical stimulants of LVCFs (e.g., capsaicin, phenylbiguanide, and α,β-methylene-ATP) in intact anesthetized females. Rats subjected to OVX prior to IH exposure exhibited an augmented apneic response to the same dose of stimulants compared with rats subjected to other treatments. Apneic responses to the stimulants were completely abrogated by bilateral vagotomy or perivagal capsaicin treatment, which blocked the neural conduction of LVCFs. Electrophysiological experiments revealed that in IH-exposed rats, OVX potentiated the excitability of LVCFs to stimulants. Moreover, LVCF hypersensitivity in rats subjected to OVX prior to IH exposure was accompanied by enhanced lung inflammation, which was reflected by elevated inflammatory cell infiltration in bronchoalveolar lavage fluid, lung lipid peroxidation, and protein expression of inflammatory cytokines. Supplementation with 17β-estradiol (E2) at a low concentration (30 μg/ml) but not at high concentrations (50 and 150 μg/ml) prevented the augmenting effects of OVX on LVCF sensitivity and lung inflammation caused by IH. These results suggest that ovarian hormones prevent the enhancement of LVCF sensitivity and lung inflammation by IH in female rats, which are related to the effect of low-dose estrogen

    Ferroelectric Control of the Conduction at the LaAlO 3 /SrTiO 3 Hetero-interface

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    Abstract The LaAlO 3 /SrTiO 3 (LAO/STO) interface serves as a model system in which a highly mobile quasi-twodimensional electron gas (2DEG) forms between two band insulator
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