100 research outputs found

    Influence on Vestibular Function by Auditory Neuropathy

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    AbstractObjectiveThe main purpose of the present study was to describe the vestibular function in patients with auditory neuropathy (AN), and to assess their ability to maintain balance.MethodsVestibular function tests were performed on 32 patients with AN and 36 normal subjects including electronystagmopraphy(ENG) and static postrography(SPG). The results from the two groups were compared.ResultsEquilibrium function in patients with AN, was abnormal, compared to normal subjects.ConclusionVestibular function tests, especially static postrography, should be performed on patients with AN

    Characteristics of transient pressure performance of horizontal wells in fractured-vuggy tight fractal reservoirs considering nonlinear seepage

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    International audienceSince the classical seepage theory has limitations in characterizing the heterogeneity of fractured-vuggy tight reservoirs, well test interpretation results are not consistent with actual production by far. Based on the nonlinear percolation theory, a new nonlinear seepage equation considering the boundary layer and yield stress was derived to describe the seepage characteristics of dense matrix blocks and the stress sensitivity and fractal features of fracture systems were characterized by applying the fractal theory. Thus, the nonlinear model of a horizontal well in a fractured-vuggy tight fractal reservoir was established naturally. Then the finite element method was applied to solve the bottom hole pressure based on the processing of internal boundary conditions. After solving the model, the seepage characteristics of different models were summarized by analyzing the bottom hole pressure dynamic curves and the sensitivity analysis of multiple parameters such the nonlinear parameter and fractal index were conducted. Finally, the practicality of the model was proved through a field application. The results show that the pressure dynamic curves can be divided into nine flow stages and the increase of the nonlinear parameter will cause the intensity of the cross flow from matrix blocks to the fracture system to decrease. The fractal index is irrelevant to the intensity of the cross flow while it decides the upwarping degree of the curve at the middle and late flow stages. On the basis of the results of the field application, it can be concluded that the model fits well with actual production and the application of this model can improve the accuracy of well test interpretation

    Identification of a novel O-conotoxin reveals an unusual and potent inhibitor of the human α9α10 nicotinic acetylcholine receptor

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    Conotoxins are a pool of disulfide-rich peptide neurotoxins produced by cone snails for predation and defense. They are a rich reservoir of novel ligands for ion channels, neurotransmitter receptors and transporters in the nervous system. In this study, we identified a novel conotoxin component, O-conotoxin GeXXVIIA, from the venom of Conus generalis. The native form of this component is a disulfide-linked homodimer of a 5-Cys-containing peptide. Surprisingly, our electrophysiological studies showed that, in comparison to the folded monomers, the linear peptide of this toxin had the highest inhibitory activity at the human α9α10 nicotinic acetylcholine receptor (nAChR), with an IC50 of 16.2 ± 1.4 nM. The activities of the N-terminal and C-terminal halves of the linear toxin are markedly reduced compared with the full-length toxin, suggesting that the intact sequence is required to potently inhibit the hα9α10 nAChR. α9α10 nAChRs are expressed not only in the nervous system, but also in a variety of non-neuronal cells, such as cochlear hair cells, keratinocytes, epithelial and immune cells. A potent inhibitor of human α9α10 nAChRs, such as GeXXVIIA, would facilitate unraveling the functions of this nAChR subtype. Furthermore, this unusual nAChR inhibitor may lead to the development of novel α9α10 nAChR-targeting drugs

    Few-femtosecond Electron Beam with THz-frequency Wakefield-driven Compression

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    We propose and demonstrate a novel method to produce few-femtosecond electron beam with relatively low timing jitter. In this method a relativistic electron beam is compressed from about 150 fs (rms) to about 7 fs (rms, upper limit) with the wakefield at THz frequency produced by a leading drive beam in a dielectric tube. By imprinting the energy chirp in a passive way, we demonstrate through laser-driven THz streaking technique that no additional timing jitter with respect to an external laser is introduced in this bunch compression process, a prominent advantage over the conventional method using radio-frequency bunchers. We expect that this passive bunching technique may enable new opportunities in many ultrashort-beam based advanced applications such as ultrafast electron diffraction and plasma wakefield acceleration.Comment: 5 pages, 4 figure

    Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model

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    Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter

    Flexible lignin carbon membranes with surface ozonolysis to host lean lithium metal anodes for nickel-rich layered oxide batteries

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    Abstract(#br)The implementation of the high-capacity Li metal anode in practical batteries has not been successful due to the short lifespan and severe safety concerns resulting primarily from low Coulombic efficiency and Li dendritic growth. Lightweight carbon skeletons are considered promising for hosting the lithium metal anode to overcome these limitations. Furthermore, the lithium metal loading must be minimized from the cost and safety standpoint, leading to the need of developing long cycle life “lean Li metal anodes”. Herein, we report a surface ozonolysis approach to homogenize Li nucleation sites and to guide the uniform Li metal deposition on flexible oxygen-enriched lignin-derived carbon membranes (OLCMs). The resulting lean OLCM@Li composite anode allows for stable Coulombic efficiency (>98% over 230 cycles), long cycle life (>1, 000 h), and small voltage hysteresis (<20 mV) in OLCM@Li||Li cells. When assembled in nickel-rich layered oxide batteries with the LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode, the lean OLCM@Li composite anode enables highly reversible capacity, high Li utilization, and improved cell cycle life. Therefore, the low-cost and mild surface ozonolysis processed lignin-based carbon membranes represent a promising class of materials for stabilizing lean Li metal anodes

    Effect of Different Ultrasonic Power on the Properties of RHA Steel Welded Joints

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    Based on the changes of microhardness, tensile strength, and impact resistance caused by the difference of macroscopic morphology and microstructure of welded joints, this paper studied the effect of different ultrasonic power on the properties of welded joints during the welding of homogeneous armor steel. It is experimentally found that the macroscopic morphology of those joints is very different. Compared with conventional welding, ultrasonic welding can increase the weld depth and the width of the heat-affected zone (HAZ) on either side of the weld. However, only the ultrasonic wave at an appropriate power level can increase the weld width. In addition, appropriate ultrasonic power can significantly improve the grain state of the weld. With the increase of ultrasonic power, the grain size in HAZ will decrease. The microhardness of the weld will first increase and then decrease, while the microhardness of the HAZ will increase. This is basically consistent with the changing trend of impact resistance. An ultrasonic wave can also increase the tensile strength of a welded joint up to 802 MPa, 12.4% higher than that in conventional welding. However, a high-power ultrasonic wave will bring down the tensile strength. This study provides guidance for the selection of ultrasonic-assisted regulation power to achieve the different properties of homogeneous armor steel joints
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