5,664 research outputs found
Gapless topological Fulde-Ferrell superfluidity in spin-orbit coupled Fermi gases
Topological superfluids usually refer to a superfluid state which is gapped
in the bulk but metallic at the boundary. Here we report that a gapless,
topologically non-trivial superfluid with inhomogeneous Fulde-Ferrell pairing
order parameter can emerge in a two-dimensional spin-orbit coupled Fermi gas,
in the presence of both in-plane and out-of-plane Zeeman fields. The
Fulde-Ferrell pairing - induced by the spin-orbit coupling and in-plane Zeeman
field - is responsible for this gapless feature. This exotic superfluid has a
significant Berezinskii-Kosterlitz-Thouless (BKT) transition temperature and
has robust Majorana edge modes against disorder owing to its topological
nature.Comment: 5 pages, 5 figures; add the results on the critical BKT temperature
and superfluid density, as well as the discussion on the robustness of the
chiral edge states against disorde
The basic properties of the electronic structure of the oxygen-evolving complex of photosystem II are not perturbed by Ca 2+ removal
Ca2+ is an integral component of the Mn4O5Ca cluster of the oxygen-evolving complex in photosystem II (PS II). Its removal leads to the loss of the water oxidizing functionality. The S2ā² state of the Ca2+-depleted cluster from spinach is examined by X- and Q-band EPR and 55Mn electron nuclear double resonance (ENDOR) spectroscopy. Spectral simulations demonstrate that upon Ca2+ removal, its electronic structure remains essentially unaltered, i.e. that of a manganese tetramer. No redistribution of the manganese valence states and only minor perturbation of the exchange interactions between the manganese ions were found. Interestingly, the S2ā² state in spinach PS II is very similar to the native S2 state of Thermosynechococcus elongatus in terms of spin state energies and insensitivity to methanol addition. These results assign the Ca2+ a functional as opposed to a structural role in water splitting catalysis, such as (i) being essential for efficient proton-coupled electron transfer between YZ and the manganese cluster and/or (ii) providing an initial binding site for substrate water. Additionally, a novel 55Mn2+ signal, detected by Q-band pulse EPR and ENDOR, was observed in Ca2+-depleted PS II. Mn2+ titration, monitored by 55Mn ENDOR, revealed a specific Mn2+ binding site with a submicromolar KD. Ca2+ titration of Mn2+-loaded, Ca2+-depleted PS II demonstrated that the site is reversibly made accessible to Mn2+ by Ca2+ depletion and reconstitution. Mn2+ is proposed to bind at one of the extrinsic subunits. This process is possibly relevant for the formation of the Mn4O5Ca cluster during photoassembly and/or D1 repair
IFN-gamma is associated with risk of Schistosoma japonicum infection in China.
Before the start of the schistosomiasis transmission season, 129 villagers resident on a Schistosoma japonicum-endemic island in Poyang Lake, Jiangxi Province, 64 of whom were stool-positive for S. japonicum eggs by the Kato method and 65 negative, were treated with praziquantel. Forty-five days later the 93 subjects who presented for follow-up were all stool-negative. Blood samples were collected from all 93 individuals. S. japonicum soluble worm antigen (SWAP) and soluble egg antigen (SEA) stimulated IL-4, IL-5 and IFN-gamma production in whole-blood cultures were measured by ELISA. All the subjects were interviewed nine times during the subsequent transmission season to estimate the intensity of their contact with potentially infective snail habitats, and the subjects were all re-screened for S. japonicum by the Kato method at the end of the transmission season. Fourteen subjects were found to be infected at that time. There was some indication that the risk of infection might be associated with gender (with females being at higher risk) and with the intensity of water contact, and there was evidence that levels of SEA-induced IFN-gamma production were associated with reduced risk of infection
A Markov Process Inspired Cellular Automata Model of Road Traffic
To provide a more accurate description of the driving behaviors in vehicle
queues, a namely Markov-Gap cellular automata model is proposed in this paper.
It views the variation of the gap between two consequent vehicles as a Markov
process whose stationary distribution corresponds to the observed distribution
of practical gaps. The multiformity of this Markov process provides the model
enough flexibility to describe various driving behaviors. Two examples are
given to show how to specialize it for different scenarios: usually mentioned
flows on freeways and start-up flows at signalized intersections. The agreement
between the empirical observations and the simulation results suggests the
soundness of this new approach.Comment: revised according to the helpful comments from the anonymous
reviewer
Correlation between Myocardial Velocity Measured using Tissue Doppler Imaging in the Left Ventricular Lead-Implanted Segment and Response to Cardiac Resynchronization Therapy
OBJECTIVES: This study investigated whether tissue Doppler imaging parameters, especially the peak systolic velocity of the left ventricular lead-implanted segment (Ss), affect cardiac resynchronization therapy response. METHODS: In this case-control study, 110 enrolled patients were divided into cases (responder group, n=65) and controls (nonresponder group, n=45) based on whether their left ventricular end-systolic volume was reduced by X15% at 6 months after surgery. Preoperative clinical and echocardiographic data were collected. Multivariate logistic regression models were used to analyze the factors affecting the response to cardiac resynchronization therapy, and receiver operating characteristic curves were plotted to evaluate their diagnostic values. RESULTS: The proportion of patients with left bundle branch block in the case group was higher than that in the control group. The control group showed a higher left atrial volume index, E/A ratio and E/Em ratio but lower Ss than that of the case group. A multivariate regression analysis showed that left bundle branch block, Ss, and an E/Em ratio414 were independent risk factors affecting the response to cardiac resynchronization therapy. Ss=4.1 cm/s was the best diagnostic threshold according to the receiver operating characteristic curve. CONCLUSIONS: Ss is an important factor affecting the response to cardiac resynchronization therapy. Patients with heart failure associated with Sso4.1 cm/s have a higher risk of nonresponse
Abnormal diastolic function underlies the different beneficial effects of cardiac resynchronization therapy on ischemic and non-ischemic cardiomyopathy
OBJECTIVES: To investigate the association between diastolic function and the different beneficial effects of cardiac resynchronization therapy in patients with heart failure due to different causes. METHODS: The 104 enrolled patients were divided into an ischemic cardiomyopathy group (n=27) and a non-ischemic cardiomyopathy group (n=77) according to the cause of heart failure. Before implantation, left ventricular diastolic function was evaluated in all patients using echocardiography. After six months of follow-up, the beneficial effects of cardiac resynchronization therapy were evaluated using a combination of clinical symptoms and echocardiography parameters. RESULTS: The ischemic cardiomyopathy group included significantly more patients with restrictive filling than the non-ischemic cardiomyopathy group. The response rate after the implantation procedure was significantly higher in the non-ischemic cardiomyopathy group than in the ischemic cardiomyopathy group. Degrees of improvement in echocardiography parameters were significantly greater in the non-ischemic cardiomyopathy group than in the ischemic cardiomyopathy group. Multivariate regression analysis showed that a restrictive filling pattern was an independent factor that influenced responses to cardiac resynchronization therapy. CONCLUSIONS: This study again confirmed that the etiology of heart failure affects the beneficial effects of cardiac resynchronization therapy and a lower degree of improvement in ventricular systolic function and remodelling was observed in ischemic cardiomyopathy patients than in non-ischemic cardiomyopathy patients. In addition, systolic heart failure patients with severe diastolic dysfunction had poor responses to cardiac resynchronization therapy. Ischemic cardiomyopathy patients exhibited more severe diastolic dysfunction than non-ischemic cardiomyopathy patients, which may be a reason for the reduced beneficial effect of cardiac resynchronization therapy
Loss of Cyclin-Dependent Kinase 5 from Parvalbumin Interneurons Leads to Hyperinhibition, Decreased Anxiety, and Memory Impairment
Perturbations in fast-spiking parvalbumin (PV) interneurons are hypothesized to be a major component of various neuropsychiatric disorders; however, the mechanisms regulating PV interneurons remain mostly unknown. Recently, cyclin-dependent kinase 5 (Cdk5) has been shown to function as a major regulator of synaptic plasticity. Here, we demonstrate that genetic ablation of Cdk5 in PV interneurons in mouse brain leads to an increase in GABAergic neurotransmission and impaired synaptic plasticity. PVCre;fCdk5 mice display a range of behavioral abnormalities, including decreased anxiety and memory impairment. Our results reveal a central role of Cdk5 expressed in PV interneurons in gating inhibitory neurotransmission and underscore the importance of such regulation during behavioral tasks. Our findings suggest that Cdk5 can be considered a promising therapeutic target in a variety of conditions attributed to inhibitory interneuronal dysfunction, such as epilepsy, anxiety disorders, and schizophrenia.National Alliance for Research on Schizophrenia and Depression (U.S.) (Young Investigator Award)National Institutes of Health (U.S.) (Grant RO1-NS051874-16)Simons Foundation (Autism Research Initiative Grant
SAPPHIRE: Search for exotic parity-violation interactions with quantum spin amplifiers
Quantum sensing provides sensitive tabletop tools to search for exotic
spin-dependent interactions beyond the Standard Model, which has attracted
great attention in theories and experiments. Here we develop a technique based
on quantum Spin Amplifier for Particle PHysIcs REsearch (SAPPHIRE) to
resonantly search for exotic interactions, specifically parity-odd spin-spin
interactions. The present technique effectively amplifies the pseudomagnetic
field generated by exotic interactions by a factor of about 200 while being
insensitive to spurious external magnetic fields. Our studies, using such a
quantum amplification technique, open the doors to exploring the
parity-violation interactions mediated by Z' bosons in the challenging
parameter space (force range between 3 mm and 0.1 km) and set the most
stringent constraints on Z'-mediated electron-neutron couplings, significantly
improving previous limits by up to five orders of magnitude. Moreover, our
bounds on Z'-mediated couplings between nucleons reaches into a hitherto
unexplored parameter space (force range below 1 m), complementing the existing
astrophysical and laboratory studies.Comment: 8 pages, 5 figure
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