20 research outputs found

    Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

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    Extreme ultraviolet (EUV) spectra emitted from aluminum in the 5-340 A wavelength range were observed in Experimental Advanced Superconducting Tokamak (EAST) discharges. Several spectral lines from aluminum ions with different degrees of ionization were successfully observed with sufficient spectral intensities and resolutions using three fast-time-response EUV spectrometers. The line identification uses three independent state-of-art computational codes for the atomic structure calculations, which provide the wavelengths and radiative transition probabilities rate coefficients. These programs are HULLAC (Hebrew University - Lawrence Livermore Atomic Code), AUTOSTRUCTURE, and FAC (Flexible Atomic Code). Using three different codes allows us to resolve some ambiguities in identifying certain spectral lines and assess the validity of the theoretical predictions

    Removal of inferior vena cava filter by open surgery after failure of endovenous retrieval

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    BackgroundThe permanent placement of inferior vena cava (IVC) filters may lead to numerous complications and their removal is recommended once the risk of pulmonary embolism is reduced. Removal of IVC filters by endovenous means is preferred. But failure of endovenous removal happens when recycling hooks penetrate the vein wall and filters are left in place for too long time. In these scenarios, open surgery may be effective for removal of IVC filters. We aimed to describe the surgical approach, outcomes, and 6-month follow-up of the removal of IVC filter by open surgery, after the failure of removal via the endovenous method.MethodsA total of 1,285 patients with retrievable IVC filters were admitted from July 2019 to June 2021, including 1,176 (91.5%) endovenous filter removals, and 24 (1.9%) open surgical IVC filter removals after the failure by endovenous method, of whom 21 (1.6%) were followed-up and eligible for analysis of the study. Patient characteristics, filter type, filter removal rate, IVC patency rate, and complications were retrospectively analyzed.ResultsTwenty-one patients were left with IVC filters for 26 (10, 37) months, of which 17 (81.0%) patients had non-conical filters and 4 (19.0%) had conical filters; all 21 filters were successfully removed, with a 100% removal rate, no deaths, no serious complications, and no symptomatic pulmonary embolism. At the 3rd month follow-up after surgery and 3rd month follow-up after discontinuation of anticoagulation therapy, only 1 case (4.8%) had IVC occlusion, but without any occurrence of new lower limb deep venous thrombosis and silent pulmonary embolism.ConclusionOpen surgery can be used for the removal of IVC filters after failure of removal by endovenous method or when accompanied by complications without symptoms of pulmonary embolism. Open surgical approach can be used as an adjunctive clinical intervention for the removal of such filters

    First Isolation and Characteristics of Bovine Parainfluenza Virus Type 3 from Yaks

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    The yaks belong to the genus Bos within the family Bovidae that live in the Tibet Plateau and is an indispensable economic resource for the local herders. Respiratory tract infections are common diseases in yaks caused by various pathogens; however, there have been no reports of bovine parainfluenza virus type 3 (BPIV3) infection. This study was conducted to investigate the pathogens and analyze their characteristics from the four yak lung samples with severe respiratory tract infection symptoms in the yak farm. Results showed that out of four lung samples, three were identified as BPIV3-positive by RT-PCR. A BPIV3 strain (106.5 TCID50/mL) was successfully isolated from the BPIV3-positive lung samples using Madin–Darby bovine kidney cells. The isolate caused systemic infection in the BALB/c mice and induced pathological changes in the lungs. Moreover, three complete BPIV3 genomes were amplified from the clinical samples. Phylogenetic trees based on the complete genomes, hemagglutinin-neuraminidase protein (HN), phosphoprotein (P), and large polymerase subunit protein (L) amino acid sequences showed that the complete BPIV3 genomes belonged to BPIV3 genotype C, and clustered into a large branch with the Chinese strains, although the three yak BPIV3 strains were clustered into a small branch. Compared to known BPIV3 genotype C strains in GenBank, the three genomes of yak BPIV3 showed four identical amino acid mutations in the HN, P and L proteins, suggesting a unique genetic evolution of BPIV3 in yaks. This study first isolated and characterized the BPIV3 from yaks, which contributed to the understanding of the infection and evolution of BPIV3 in yaks in the Tibet Plateau

    Current status and perspectives of patient-derived xenograft models in cancer research

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    Abstract Cancers remain a major public health problem worldwide, which still require profound research in both the basic and preclinical fields. Patient-derived xenograft (PDX) models are created when cancerous cells or tissues from patients’ primary tumors are implanted into immunodeficient mice to simulate human tumor biology in vivo, which have been extensively used in cancer research. The routes of implantation appeared to affect the outcome of PDX research, and there has been increasing applications of patient-derived orthotopic xenograft (PDOX) models. In this review, we firstly summarize the methodology to establish PDX models and then go over recent application and function of PDX models in basic cancer research on the areas of cancer characterization, initiation, proliferation, metastasis, and tumor microenvironment and in preclinical explorations of anti-cancer targets, drugs, and therapeutic strategies and finally give our perspectives on the future prospects of PDX models

    Marginal utility of battery energy storage capacity for power system economic dispatch

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    The battery energy storage (BES) is recognized as a key resource for the power fluctuations smoothing, peak load shaving and frequency regulation, and its performance depends heavily on the available capacity. It is meaningful to investigate the influence of the BES capacity on the power system operation cost. This paper focuses on the marginal utility of BES capacity in the day-ahead power system operation cost. Firstly, the day-ahead economic dispatch problem is formulated as a constrained quadratic programming problem, with the consideration of the BES degradation cost. Then, the relationship between the BES-related shadow prices and the marginal electricity price is derived from the KKT conditions of the dispatch problem. Based on it, the marginal utility of BES capacity is modeled to evaluate the effect of BES capacity on the system day-ahead operation cost. Finally, the numerical results demonstrate that the proposed marginal utility can manifest the influence of BSS capacity on the power system operation

    Control of Rock Block Fragmentation Based on the Optimization of Shaft Blasting Parameters

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    In the construction of shaft, the blockage of the mucking shaft may cause the mud-water inrush disaster. Oversized rock fragmentation is the main cause for the blockage of the mucking shaft in the raise boring machine (RBM) construction method. The influence degree of blasting parameters on rock fragmentation after blasting is quantified by adopting analytic hierarchy process (AHP). On this basis, the shaft blasting maximum rock fragmentation control model based on double hidden layer BP neural network is proposed. Results show that the maximum rock fragmentation discharged from the mucking shaft after blasting should not exceed 1/3 of the diameter of the slag chute. The influence weight of the minimum resistance line that accounts to 15.6%, when AHP is applied for the quantification of the blasting parameters, can be regarded as the most important blasting parameter. The average absolute errors between the predicted value and the actual value of the largest block size control model of the shaft blasting are only 2.6%. The inversion analysis of the model can rapidly obtain the required blasting parameters, which can be used to guide the construction of the tunnel ventilation shaft

    The Voltage Regulation Control Strategy with Distributed Photovoltaic Participation under Serious Failure Based on Transient Voltage Margin

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    With the poor ability of distributed PV to withstand voltage fluctuation, the voltage fluctuation caused by DC blocking can lead to large-scale disorderly de-networking of distributed PV, especially those distributed PV which close to voltage weak buses. which means that more and more attentions are paid to the transient voltage stability (TVS). If distributed PV can participation in reactive compensation, we don’t need to add additional reactive power compensator, voltage stability of voltage weak buses will be increased, which can reduce PV off-grid. Therefore, for the HVDC receiving end system under distributed PV intensive access, first of all, we need to find the voltage weak bus, then increase the reactive power output of distributed PV near the voltage weak buses to increase transient voltage margin. Taking the simplified model of power system in Anhui Province as an example, the validity of the strategy is verified, and the results show that the transient voltage stability of the system has been improved

    Influence of pressure on filtration performance of nanofiber composite filtering material

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    Purification technology is required to separate the liquid impurities of natural gas during its transportation. However, the filtration performance of coalescing filter element used for natural gas purification at present needs to be improved. Therefore, the new filtering materials were developed by a nanofiber composite method. Besides, the permeability and gas-liquid filtration performance of the 4 types of composite filtering materials were tested with the experimental devices under the pressures from 0.1 MPa to 0.5 MPa. The results show that the Darcy coefficient of the composite filtering materials decreases with the increasing of the surface density of nanofiber, and more significant decrease is observed after the substrate with high permeability is composited with the nanofiber. Meanwhile, the increasing of operating pressure can lead to the compression of filtering material structure, which further results in the change of the mutual relationship between the Darcy coefficient and non-Darcy coefficient. Moreover, the filtration efficiency of filtering materials is improved after compositing with nanofiber, but the pressure drop also increases. Under the condition of same surface density of nanofiber, the pressure drop in oleophobic filtering material is more significant than the oleophilic filtering material. Hence, too high surface density will result in excessive pressure drop, further causing the reduction of the comprehensive performance of filtering materials. Generally, the research results could provide reference for the selection of filtering materials for natural gas purification

    High Efficiency and Low Migration Hyperbranched Silicone Contain Macrophotoinitiators for UV-Cured Transparent Coatings

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    A kind of hyperbranched silicone containing macrophotoinitiators (HBSMIs) were synthesized from 2-hydroxy-2-methyl-1-phenyl propanone (HMPP) and the UV-curing behaviors of HBSMIs were investigated in UV-cured transparent polyurethane-acrylate (PUA) coatings. HBSMIs show higher UV-initiating efficiency than HMPP. The migration of HBSMIs from the UV-cured coatings can be as low as 1.7–6.0 wt%, which is obviously lower than the migration of HMPP. There is a remarkable improvement of the tensile strength of the UV-cured materials initiated by HBSMI in comparison to that of the materials prepared with the same PUA initiated by HMPP. Especially for the UV-cured materials prepared from PUA with 20 wt% 1,1,1-tris(hydroxymethyl)propane (TMP), the tensile strength and the strain at break increased from 6.81 MPa to 12.14 MPa and from 43.0% to 71.9%, respectively. The fraction of improvement for the tensile strength and the strain at break is as high as 78.9% and 67.2%, respectively. The coatings prepared with HBSMI also have better UV resistance ability than those coatings prepared with HMPP because they turn slightly yellow when they are aged by UV for about 15 min while the coating prepared with 4 wt% of HMPP will turn yellow only aged by UV for 2 min. These results suggest that preparation hyperbranched silicone containing macrophotoinitiators will be one of the good strategies to improve the curing efficiency of the UV-curing system, reduce the migration of UV initiator from cured material, improve the mechanical and UV resistance performance of UV-cured materials
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