3,978 research outputs found
Universal impurity-induced bound state in topological superfluids
We predict a universal mid-gap bound state in topological superfluids,
induced by either non-magnetic or magnetic impurities in the strong scattering
limit. This universal state is similar to the lowest-energy Caroli-de
Gennes-Martricon bound state in a vortex core, but is bound to localized
impurities. We argue that the observation of such a universal bound state can
be a clear signature for identifying topological superfluids. We theoretically
examine our argument for a spin-orbit coupled ultracold atomic Fermi gas
trapped in a two-dimensional harmonic potential, by performing extensive
self-consistent calculations within the mean-field Bogoliubov-de Gennes theory.
A realistic scenario for observing universal bound state in ultracold K
atoms is proposed.Comment: 5 pages + 4 figures; published in PRL; see the relevant study in 1D:
Phys. Rev. A 87, 013622 (2013); see also the accompanying Physics Synopsis:
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.110.02040
Probing behaviors of Sitobion avenae (Hemiptera: Aphididae) on enhanced UV-B irradiated plants
UV-B induced changes in plants can influence sap-feeding insects through mechanisms that have not been studied. Herein the grain aphid, Sitobion avenae (Fabricius) (Hemiptera: Aphididae), was monitored on barley plants under the treatments of control [0 kJ/ (m2.d)], ambient UV-B [60 kJ/ (m2.d)], and enhanced UV-B [120 kJ/ (m2.d)] irradiation. Electrical penetration graph (EPG) techniques were used to record aphid probing behaviors. Enhanced UV-B irradiated plants negatively affected probing behaviors of S. avenae compared with control plants. In particular, phloem factors that could diminish sieve element acceptance appeared to be involved, as reflected by smaller number of phloem phase, shorter phloem ingestion, and fewer aphids reaching the sustained phloem ingestion phase (E2>10min). On the other hand, factors from leaf surface, epidermis, and mesophyll cannot be excluded, as reflected by higher number of non-probing, longer non-probing and pathway phase, and later the time to first probe
Suppression of experimental arthritis through AMP-activated protein kinase activation and autophagy modulation
Autophagy plays a central role in various disease processes. However, its contribution to inflammatory arthritides such as rheumatoid arthritis (RA) is unclear. We observed that autophagy is engaged in the K/BxN serum transfer model of RA but autophagic flux is severely impaired. Metformin is an anti-diabetic drug that has been shown to stimulate autophagy. Induction of autophagic flux, through metformin-mediated AMP-activated protein kinase (AMPK) activation and interruption of mammalian target of rapamycin (mTOR) signaling mitigated the inflammation in experimental arthritis. Further investigation into the effects of metformin suggest that the drug directly activates AMPK and dose-dependently suppressed the release of TNF-α, IL-6, and MCP-1 by macrophages while enhancing the release of IL-10 in vitro. In vivo, metformin treatment significantly suppressed clinical arthritis and inflammatory cytokine production. Mechanistic studies suggest that metformin exerts its anti-inflammatory effects by correcting the impaired autophagic flux observed in the K/BxN arthritis model and suppressing NF-κB-mediated signaling through selective degradation of IκB kinase (IKK). These findings establish a central role for autophagy in inflammatory arthritis and argue that autophagy modulators such as metformin may represent potential therapeutic agents for the treatment of RA
Synergistic Effect of Trehalose and Saccharose Pretreatment on Maintenance of Lyophilized Human Red Blood Cell Quality
Purpose: To investigate the synergistic effect of trehalose and saccharose pretreatment on maintenance of lyophilized human red blood cell (RBC) quality.Methods: RBCs were pre-treated with trehalose and saccharose, and then lyophilized and re-hydrated. Prior to lyophilization and after re hydration, RBC parameters, RBC counts, total hemoglobin concentration, mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), comprehensive deformation index, hemolysis ratio and phosphatidylserine (PS) expression, were determined using a hematology analyzer, an RBC deformation instrument, a spectrophotometer and a flow cytometer, respectively. Superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G-6-PD), and adenosine triphosphatase (ATPase) activities were determined using kits for SOD, ATPase, and G-6- PD assay, respectively.Results: After lyophilization-rehydration, RBC counts and total hemoglobin recovery rates, deformability, and RBC SOD, ATPase, and G-6-PD activities were significantly decreased by 47.24 – 74.65 % (p < 0.01), compared with the normal group. RBC osmotic fragility and PS expression on the outer surface of the RBC membrane were significantly increased by 168.53 and 629.30 % (p < 0.01), respectively, compared with the normal group. RBC MCH and MCV values were not significantly affected by lyophilization rehydration (p > 0.05). Trehalose and saccharose pretreatment significantly reversed the effects of lyophilization-rehydration on these RBC parameters by approximately 13.16 – 211.11 % (p < 0.01), compared with the control group. The combined effects were synergistic.Conclusion: Trehalose and saccharose pretreatment synergistically enhances maintenance of lyophilized RBC quality.Keywords: Trehalose, Saccharose, Lyophilization, Red blood cell, Hematological parameter
Interaction-Driven Active 3D Reconstruction with Object Interiors
We introduce an active 3D reconstruction method which integrates visual
perception, robot-object interaction, and 3D scanning to recover both the
exterior and interior, i.e., unexposed, geometries of a target 3D object.
Unlike other works in active vision which focus on optimizing camera viewpoints
to better investigate the environment, the primary feature of our
reconstruction is an analysis of the interactability of various parts of the
target object and the ensuing part manipulation by a robot to enable scanning
of occluded regions. As a result, an understanding of part articulations of the
target object is obtained on top of complete geometry acquisition. Our method
operates fully automatically by a Fetch robot with built-in RGBD sensors. It
iterates between interaction analysis and interaction-driven reconstruction,
scanning and reconstructing detected moveable parts one at a time, where both
the articulated part detection and mesh reconstruction are carried out by
neural networks. In the final step, all the remaining, non-articulated parts,
including all the interior structures that had been exposed by prior part
manipulations and subsequently scanned, are reconstructed to complete the
acquisition. We demonstrate the performance of our method via qualitative and
quantitative evaluation, ablation studies, comparisons to alternatives, as well
as experiments in a real environment.Comment: Accepted to SIGGRAPH Asia 2023, project page at
https://vcc.tech/research/2023/InterReco
MicroRNA-155 Attenuates Late Sepsis-Induced Cardiac Dysfunction Through JNK and β-Arrestin 2
Cardiac dysfunction is correlated with detrimental prognosis of sepsis and contributes to a high risk of mortality. After an initial hyperinflammatory reaction, most patients enter a protracted state of immunosuppression (late sepsis) that alters both innate and adaptive immunity. The changes of cardiac function in late sepsis are not yet known. MicroRNA-155 (miR-155) is previously found to play important roles in both regulations of immune activation and cardiac function. In this study, C57BL/6 mice were operated to develop into early and late sepsis phases, and miR-155 mimic was injected through the tail vein 48 h after cecal ligation and puncture (CLP). The effect of miR-155 on CLP-induced cardiac dysfunction was explored in late sepsis. We found that increased expression of miR-155 in the myocardium protected against cardiac dysfunction in late sepsis evidenced by attenuating sepsis-reduced cardiac output and enhancing left ventricular systolic function. We also observed that miR-155 markedly reduced the infiltration of macrophages and neutrophils into the myocardium and attenuated the inflammatory response via suppression of JNK signaling pathway. Moreover, overexpression of β-arrestin 2 (Arrb2) exacerbated the mice mortality and immunosuppression in late sepsis. Furthermore, transfection of miR-155 mimic reduced Arrb2 expression, and then restored immunocompetence and improved survival in late septic mice. We conclude that increased miR-155 expression through systemic administration of miR-155 mimic attenuates cardiac dysfunction and improves late sepsis survival by targeting JNK associated inflammatory signaling and Arrb2 mediated immunosuppression
Single Impurity In Ultracold Fermi Superfluids
The role of impurities as experimental probes in the detection of quantum
material properties is well appreciated. Here we study the effect of a single
classical magnetic impurity in trapped ultracold Fermi superfluids. Depending
on its shape and strength, a magnetic impurity can induce single or multiple
mid-gap bound states in a superfluid Fermi gas. The multiple mid-gap states
could coincide with the development of a Fulde-Ferrell-Larkin-Ovchinnikov
(FFLO) phase within the superfluid. As an analog of the Scanning Tunneling
Microscope, we propose a modified RF spectroscopic method to measure the local
density of states which can be employed to detect these states and other
quantum phases of cold atoms. A key result of our self consistent Bogoliubov-de
Gennes calculations is that a magnetic impurity can controllably induce an FFLO
state at currently accessible experimental parameters.Comment: 5 pages, 3 figures; added calculations for 3
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