136 research outputs found

    Research on source location of micro-seismic event ‎based on dynamic cluster velocity model

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    A new velocity model based on dynamic cluster was proposed in this paper. During the process ‎of iteration, the sensors can be formed a cluster according to the velocity similitude degree. ‎Based on the assumption that the speeds from source to each sensor in the same cluster are ‎equal, the corresponding objective function was proposed to solve the source location, which ‎didn’t include the velocity parameter. It not only avoided the error from field measurement ‎and the inversion, but also appropriated for the actual situation that the speeds from every ‎source to different sensors are different. By analyzing 24 different cases, the positioning ‎accuracy based on the velocity model proposed in this paper was verified to be preferable and ‎stable, no matter the source is within the region of the sensor’s array or not. Even for the cases ‎of different velocity variation ranges, the velocity model was still reliable.

    Analytical solution and numerical verification for a pressure-relief method of circular tunnel

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    This paper presents an elastic analytical solution to a circular tunnel with releasing slots at high stress areas near the hole by using a conformal mapping method and the complex variable theory. Compared to the original stress distribution around the circular hole, the releasing effect on elastic stresses is evaluated. After grooving slots, low stress area is generated where the high stress concentration is located. This is agreeable with what was predicted by the finite difference FLAC2D . Besides, displacements are obtained along the periphery of the released hole and are in accordance with those of FLAC2D . In addition to the intersection of the mapping contour, the influences of the sampling points distribution, series number in mapping function, and slot shape are discussed. It is inevitable that the mapping accuracies for the slot and the circle cannot be satisfied at the same time The mapping effect on the circle has to be considered primarily since the stress distribution around the circle is much more significant than the tunnel stability. The analytical solution can be available and fast method of estimating the releasing effect of the application on the tunnel without rock parameters

    Provirus activation plus CD59 blockage triggers antibody-dependent complement-mediated lysis of latently HIV-1-infected cells

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    Latently HIV-1-infected cells are recognized as the last barrier toward viral eradication and cure. To purge these cells, we combined a provirus stimulant with a blocker of human CD59, a key member of the regulators of complement activation, to trigger Ab-dependent complement-mediated lysis. Provirus stimulants including prostratin and histone deacetylase inhibitors such as romidepsin and suberoylanilide hydroxamic acid activated proviruses in the latently HIV-1-infected T cell line ACH-2 as virion production and viral protein expression on the cell surface were induced. Romidepsin was the most attractive provirus stimulant as it effectively activated proviruses at nanomolar concentrations that can be achieved clinically. Antiretroviral drugs including two protease inhibitors (atazanavir and darunavir) and an RT inhibitor (emtricitabine) did not affect the activity of provirus stimulants in the activation of proviruses. However, saquinavir (a protease inhibitor) markedly suppressed virus production, although it did not affect the percentage of cells expressing viral Env on the cell surface. Provirus-activated ACH-2 cells expressed HIV-1 Env that colocalized with CD59 in lipid rafts on the cell surface, facilitating direct interaction between them. Blockage of CD59 rendered provirus-activated ACH-2 cells and primary human CD4(+) T cells that were latently infected with HIV-1 sensitive to Ab-dependent complement-mediated lysis by anti-HIV-1 polyclonal Abs or plasma from HIV-1-infected patients. Therefore, a combination of provirus stimulants with regulators of complement activation blockers represents a novel approach to eliminate HIV-1

    Basic Research on Rockburst Control Technology for Deep Well Filling of Municipal Solid Waste

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    AbstractGiven the scarcity of raw materials for rockburst prevention in filling mining and the lack of space for disposal of large amount of municipal waste, the feasibility of preparing filling materials for rockburst mines from stale waste was investigated by laboratory tests and theoretical analysis. On this basis, the process of preparing filling materials from stale garbage was proposed, and corresponding equipment were developed to prepare stale garbage filling mass. According to the characteristics and uses of the stale waste filling materials, two processes of volume filling and strength filling are proposed, and the key technology of stale garbage filling to control rockburst was designed. The following conclusions were drawn: stale garbage can be made into mine filling material because of its composition, strength, and shape. The process of preparing mine filling materials from obsolete waste includes crushing, screening, compression, and packaging. The equipment suitable for the process includes crushing-screening, compression-forming, and sealing-packaging integrated equipment. The equipment has realized effective screening, compression, and bulk packaging of stale garbage, so that the stale garbage filling mass can meet the requirements of environmental protection and strength. Strength filling is a filling method that uses the strength of stale garbage filling mass to protect the overlying strata from or less damage, thereby reducing the stress concentration in the coal face and reducing the risk of rockburst occurring. Volume filling mainly depends on the volume of the filling mass, with the main purpose of reducing the stress concentration in the roadway surrounding rock. The rockburst mine filling technology of stale garbage is support track filling technology and bag filling technology, and the deep well sealing of stale garbage is block stacking technology. The deep well filling mining key technologies provide a new approach to against rockburst and treat large amounts of municipal waste

    Two-Step Sequential Blade-Coating Large-Area FA-Based Perovskite Thin Film via a Controlled PbI2 Microstructure

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    Solar cells, which are excellent alternatives to traditional fossil fuels, can efficiently convert sunlight into electricity. The intensive development of high-performance photovoltaic materials plays an important role in environmental protection and the utilization of renewable energy. Organic??? inorganic hybrid perovskite materials, with a formula of ABX3 (A = methylammonium (MA) or formamidinium (FA); B = Pb or Sn; X = Cl, I, or Br), have exhibited remarkable commercial prospects in high-performance photovoltaic devices owing to their long carrier diffusion length, excellent light absorption properties, high charge carrier mobility, and weak exciton binding energy. Recently, perovskite solar cells, fabricated using halide perovskite materials as light-absorbing layers, have achieved remarkable results; their certified power conversion efficiency has continuously improved and reached 25.7%. However, high-performance devices are usually fabricated using spin-coating methods with active areas below 0.1 cm2. Hence, long-term research goals include achieving a large-scale uniform preparation of high-quality photoactive layers. The current one-step preparation of perovskite films involves the nucleation-crystalline growth process of perovskite. Auxiliary processes, such as using an anti-solvent, are often required to increase the nucleation rate and density of the film, which is not suitable for industrial large-area preparation. Additionally, the large-area preparation of perovskite films by spin-coating will result in different film thicknesses in the center and edge regions of the film due to an uneven centrifugal force. This will cause intense carrier recombination in the thicker area of the film and weak light absorption in the thinner area, which will reduce the performance of the device. To address these problems, the development of a large-area fabrication method for high-performance perovskite light-absorbing layers is essential. In this study, a two-step sequential blade-coating strategy was developed to prepare the FA-based perovskite layer. In general, PbI2 easily forms a dense film; therefore, formamidinium iodide (FAI) cannot deeply penetrate to completely react with PbI2. The PbI2 residue is therefore detrimental to charge transportation. To fabricate the desired porous PbI2 film, tetrahydrothiophene 1-oxide (THTO) was introduced into the PbI2 precursor solution. By forming PbI2??THTO complexes, PbI2 crystallization is controlled, resulting in the formation of vertically packed PbI2 flaky crystals. These crystals provide nanochannels for easy FAI penetration. The 5 cm ?? 5 cm modules fabricated through this strategy achieved a high efficiency of 18.65% with excellent stability. This indicates that the two-step sequential blade-coating strategy has considerable potential for scaling up the production of perovskite solar cells

    Preliminary investigation of the effect of non-cardiac surgery on intraoperative islet and renal function: a single-center prospective cohort study

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    BackgroundThe effect of different non-cardiac surgical methods on islet and renal function remains unclear. We conducted a preliminary investigation to determine whether different surgical methods affect islet function or cause further damage to renal function.MethodsIn this prospective cohort study, the clinical data of 63 adult patients who underwent non-cardiac surgery under general anesthesia were evaluated from February 2019 to January 2020. Patients were divided into the abdominal surgery group, the laparoscopic surgery group, and the breast cancer surgery group. The primary outcome was the difference between the effects of different surgical methods on renal function.ResultsIslet and renal function were not significantly different between the groups. The correlation analysis showed that hematocrit (HCT) and hemoglobin (HB) were negatively correlated with fasting plasma glucose (FPG) (p < 0.05), MAP was positively correlated with C-peptide (p < 0.05), and HCT and Hb were positively correlated with serum creatinine (SCr) (p < 0.05). Fasting insulin (FINS) and C-peptide were negatively correlated with SCr (p < 0.05), and the homeostatic model assessment of insulin resistance (HOMA-IR) was positively correlated with SCr (p < 0.05). FINS, C-peptide, HOMA-IR, and the homeostatic model assessment of β-cell function (HOMA-β) were positively correlated with cystatin C (Cys C) (p < 0.05).ConclusionFINS, C-peptide, and HOMA-IR had positive effects on beta-2-microglobulin (β2-MG). FINS, C-peptide, and HOMA-IR were positively correlated with Cys C and β2-Mg. While FINS and C-peptide were negatively correlated with SCr, HOMA-IR was positively correlated with SCr

    Transport of intense ion beams in plasmas: collimation and energy-loss reduction

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    We compare the transport properties of a well-characterized hydrogen plasma for low and high current ion beams. The energy-loss of low current beams can be well understood, within the framework of current stopping power models. However, for high current proton beams, significant energy-loss reduction and collimation is observed in the experiment. We have developed a new particle-in-cell code, which includes both collective electromagnetic effects and collisional interactions. Our simulations indicate that resistive magnetic fields, induced by the transport of an intense proton beam, act to collimate the proton beam and simultaneously deplete the local plasma density along the beam path. This in turn causes the energy-loss reduction detected in the experiment

    Efficacy and safety of neoadjuvant immunotherapy in resectable esophageal or gastroesophageal junction carcinoma: A pooled analysis of prospective clinical trials

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    Neoadjuvant chemoradiotherapy (NCRT) plus radical esophagectomy is currently the standard treatment for resectable esophageal or gastroesophageal junction (GEJ) carcinoma. The aim of this study is to evaluate the efficacy and safety of neoadjuvant immunotherapy in resectable esophageal or GEJ carcinoma. Prospective clinical trials investigating efficacy and/or safety of neoadjuvant immunotherapy with immune checkpoint inhibitors (ICIs) followed by radical esophagectomy in patients with newly diagnosed resectable esophageal or GEJ carcinoma were identified through literature search. Quality assessment was performed by using the Newcastle–Ottawa scale. Preliminary treatment outcomes of pathologically complete response (pCR, ypT0N0) and grade 3-4 adverse effects (AEs) were pooled together and then compared with standard NCRT of the historical control CROSS study by Chi-square (χ2) test. A two-sided P value < 0.05 was considered statistically significant. A total of 17 eligible non-randomized trials with 455 participants were included into analysis. The most common primary endpoint was pCR (n = 7, 41%), and the median sample size and follow-up period was 23 patients and 7.9 months, respectively. For patients receiving neoadjuvant immunotherapy, the overall pCR, R0 resection, and grade 3-4 AE rates were 33.2%, 95.5%, and 35.1%, respectively. For esophageal squamous cell carcinoma (ESCC) and adenocarcinoma (EAC), neoadjuvant immunochemoradiotherapy showed no significant improvement in pCR rate than NCRT (ESCC, 50% vs 48.7%, P = 0.9; EAC, 32.6% vs 23.1%, P = 0.22). Grade 3-4 AEs were the most common in patients with neoadjuvant immunochemoradiotherapy, significantly higher than immunochemotherapy (46.7% vs 32.8%, P = 0.04) and NCRT (46.7% vs 18.1%, P < 0.0001). In conclusion, for patients with resectable esophageal or GEJ carcinoma, the addition of ICIs to standard NCRT could not improve pCR rate in both ESCC and EAC, but significantly increased the risk of severe AEs. Large-scale phase 3 randomized trials were urgently needed to further confirm the survival benefit and safety profile of neoadjuvant immunotherapy

    Collaborative multidisciplinary management and expertise of cT2-3 locally advanced operable esophageal squamous cell carcinoma:two case reports

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    Background: The accurate clinical staging of esophageal squamous cell carcinoma (ESCC) is pivotal for guiding treatment strategies. However, the current precision in staging for clinical T (cT)2 and cT3 stages remains unsatisfactory. This article discusses the role of multidisciplinary teams (MDTs) in the clinical staging and formulation of neoadjuvant treatment strategies for locally advanced operable ESCC. These challenges underscore the importance of precise staging in the decision-making process for appropriate therapeutic interventions.Case Description: Through the lens of two patient case studies with locally advanced resectable ESCC, the article showcases the intricate process of treatment planning undertaken by MDTs. It captures a range of expert perspectives from Japan, China, Hong Kong (China), Korea, the USA, and Europe, focusing on the challenges of differentiating between cT2 and cT3 stages of the disease, which is a critical determinant in the management and therapeutic approach for patients.Conclusions: The article concludes that the accurate staging of ESCC is a cornerstone in determining the most suitable treatment strategies. It underscores the vital role that MDTs play in both clinical staging and the decision-making process for treatment. Highlighting the limitations in current diagnostic methods, the article emphasizes the urgent need for advanced research and the refinement of diagnostic tools to improve the precision of staging, particularly between the cT2 and cT3 stages. It suggests that future research should consider whether a reclassification of these stages could be warranted to enhance treatment planning and outcomes for patients with ESCC.<br/
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