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• A novel vibration isolator based on locally resonant phononic crystal is built. • The novel isolator decreases the opening band and widens the bandgap. • Isolation ability is studied by a vehicle-track-floating slab track-tunnel model. A locally resonant phononic crystal isolator (LRPCI) that the external ring vibrators attached to the central connectors through the rubber is designed, and it is installed to attenuate vibration under the track of rail transit. The energy band structure of the isolator is calculated by the finite element method, and its bandgap range is from 49.7 Hz to 104.9 Hz. The transmission loss and the equivalent mass density are further calculated to verify the accuracy of the bandgap, and they are perfectly corresponding to the bandgap. Then, the vehicle-rail-floating slab track-tunnel multibody dynamic model is built to analyse the vibration attenuation performance of the floating slab track installed the LRPCI and steel spring isolator under the train load. The results show that the LRPCI has a low frequency bandgap and can reduce the low frequency vibration, and the vibration isolation performance of the LRPCI is better than that of the steel spring isolator. The LRPCI has a low frequency bandgap, which can isolate the vibrations caused by wheel-rail interaction, and further reduce the impact of vibrations on surrounding buildings and the environment. [ABSTRACT FROM AUTHOR]

Based on the quantum valley Hall effect analogy, this work proposes a phononic crystal plate with ligament-type beams to obtain the topological valley transmission of elastic waves. A pure Bragg degenerate state appears in the high-frequency region with a resonator introduced. By rotating the central scatterer and the beams, the mirror symmetry is broken to form a topological bandgap. Subsequently, this work finds that two selective edge states also appear beside the commonly non-trivial crossing edge states in the topological bandgap by calculating the projected band and eigenvalue spectrum of the supercell with different valley Hall phases phononic crystals. Their appearance is due to band separation of the topological edge states caused by an increase in the rotation angle. Both selective edge states can transmit topologically in specific paths. They will help further to broaden the width of the frequency band of topological transmission. Besides, an elastic wave splitter is designed and demonstrated numerically, which can form two channels and three channels in different frequency bands. With the topological selective edge state disappearing, a topological corner state exists in the edge bandgap. This work provides a theoretical reference for practical applications of broadband elastic wave topological transmission and elastic energy trapping. [ABSTRACT FROM AUTHOR]

For the control of low-frequency noise in complex external-pressure environment, a new two-dimensional phononic crystal plate which is made of the lead stub with rubber coatings connected by narrow epoxy bars is proposed and the bandgap characteristics are simulated tentatively by the finite element method. The bandgap generation mechanism of the designed model is investigated by analyzing corresponding vibration modes. Furthermore, the bandgap adjustability under different pre-compression strains and geometric parameters is also investigated. Results show that obvious bandgaps tunability with small pre-compression strains or hydrostatic pressure is realized by changing geometric parameters and applying pre-compression strain to the matrix. [ABSTRACT FROM AUTHOR]

Aiming at the problem of low-frequency vibration and noise control in the engineering applications, a new two-dimensional phononic crystal consisting of cross-like copper beams embedded in silicon rubber plates with holes is designed and the bandgap characteristics are calculated by the finite element method. Meanwhile, the acoustic displacement fields of the bandgap edges are analyzed to clarify the mechanism of the bandgap generation and the effects of parameters variation on the band structure are discussed carefully. In addition, considering the application value of the model, the combination sealing plate structures with large size are further investigated and described. Results show that a wide low-frequency bandgap is opened and the generation of the bandgap is due to the out-plane torsional vibration of the cross-like beams. The bandgaps mainly depend on the matching degree of material and the geometry parameters of periodic hole, while the bandgaps are not quite sensitive to the thickness of plate. [ABSTRACT FROM AUTHOR]

Primary pulmonary non-Hodgkin's lymphoma (PP-NHL) is a rare entity with non-specific symptoms and radiographic findings, as well as a difficult preoperative diagnosis. A limited number of studies have described PP-NHL in Chinese patients. The goal of the present study was to improve early diagnosis by examining prognostic factors in patients with PP-NHL. Therefore, a total of 29 patients with PP-NHL were included in the study between January 2001 and June 2017, including 14 with aggressive-type and 15 with indolent-type lymphomas (10 male, 19 female; median age, 50.3 years; range, 19–87 years). Pulmonary nodules and masses (55.2%) were the most common radiographic features. The diagnostic yield was 80% (12/15) by endobronchial biopsy or transbronchial lung biopsy and 100% by computed tomography (CT)-guided percutaneous needle lung biopsy (11/11) or surgery (8/8). Elevated lactate dehydrogenase levels and systemic symptoms were observed considerably more often in patients with aggressive disease than in those with indolent disease. The 1-, 3- and 5-year overall survival (OS) rates were 42, 32, and 21%, respectively, for all patients, 72, 57 and 43%, respectively, for patients with indolent lymphomas, and 13, 6 and 0%, respectively, for patients with aggressive lymphomas. The median OS rate for all patients was 12.0 months; however, the OS rate for patients with aggressive lymphomas was significantly shorter compared with those with indolent lymphomas (7.1 months vs. 16.6 months; P=0.002). Aggressive vs. indolent lymphoma status was indicated to be an independent prognostic factor for poor 5-year OS rate (hazard ratio, 5.98; P=0.014). In conclusion, bronchoscopic and CT-guided percutaneous needle lung biopsies were the most useful and least invasive procedures for diagnosing PP-NHL. Furthermore, aggressive PP-NHL was highly associated with poor 5-year OS rate and a poor prognosis. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea (OSA) is much more prevalent in older people than in middle-aged or young populations, and has been associated with cardiovascular disease. Continuous positive airway pressure (CPAP) is the first-line therapy for OSA, but its long-term clinical benefit in the elderly is unclear. Here, we carried out a prospective cohort study to explore the survival rate and incidence of cardiovascular events in elderly patients with moderate to severe OSA who did or did not receive CPAP treatment. The study included 130 patients (104 male, 26 female; mean age: 77.8 ± 6.2 years) who were followed up for a mean of 5 ± 2.54 years (range, 1–8 years). Thirty-six patients received CPAP and 88 had no CPAP. The results showed that mortality in the untreated group (21.6%) was significantly higher than in the CPAP group (5.6%). Kaplan–Meier survival analysis showed that the survival rate in the CPAP group was 94.4%, which was markedly higher than the rate of 78.4% in the untreated group. The incidence of cardiovascular events was 13.9% in the CPAP group and 55.7% in the untreated group. The present study provides evidence that CPAP can reduce mortality in older patients with moderate to severe OSA, and lead to a good long-term prognosis. The study also indicates that death in older OSA patients is associated with cardiovascular disease and diabetes. [ABSTRACT FROM AUTHOR]