138 research outputs found
Sensitivity Analysis for Coupled Structural-Acoustic System with Absorbing Material Using FEM/BEM
Since the acoustic impedance in water cannot be neglected with respect to the mechanical impedance, the acoustic radiation caused by the vibration of structures in the compressible fluid would react to the structure. Therefore, the fluid-structure interaction needs to be considered. The finite element method is used for structure vibration analysis and the boundary element method for acoustic analysis. Sound absorption materials are used to reduce the scattering sound field in the reference region. The sensitivity analysis of a fully coupled structural-acoustic system is proposed. Numerical tests verify the correctness of the proposed algorithm
Study of long-termed displacements of a tunnel boring machine during its stoppage
This paper studies the long-termed displacement of a tunnel boring machine (TBM) resting on soft clay during its unscheduled stoppage for 100 days. It is based on a real case of tunneling in a coastal city of Ningbo in China. The numerical prediction is carried out by using different soil models in the software PLAXIS, and the prediction is compared with on-site measurement of the displacement. Different factors are considered in the prediction, including soil creeping and the disturbance to the soft clay during the tunneling. The study indicates that the consideration of disturbance is essential to the accurate prediction. While advanced soil models including the soft soil model and soft soil creep model are not able to accurately predict the TBM displacement, the consideration of soil disturbance leads to a very good agreement with the measurement. The accurate prediction of ground settlements also justifies consideration of the disturbance in the study of tunneling. © 2018 Elsevier Lt
Study of long-termed displacements of a tunnel boring machine during its stoppage
This paper studies the long-termed displacement of a tunnel boring machine (TBM) resting on soft clay during its unscheduled stoppage for 100 days. It is based on a real case of tunneling in a coastal city of Ningbo in China. The numerical prediction is carried out by using different soil models in the software PLAXIS, and the prediction is compared with on-site measurement of the displacement. Different factors are considered in the prediction, including soil creeping and the disturbance to the soft clay during the tunneling. The study indicates that the consideration of disturbance is essential to the accurate prediction. While advanced soil models including the soft soil model and soft soil creep model are not able to accurately predict the TBM displacement, the consideration of soil disturbance leads to a very good agreement with the measurement. The accurate prediction of ground settlements also justifies consideration of the disturbance in the study of tunneling. © 2018 Elsevier Lt
Ivermectin induces apoptosis of esophageal squamous cell carcinoma via mitochondrial pathway
Background: Esophageal squamous cell carcinoma (ESCC) is the most predominant primary malignant tumor among worldwide, especially in China. To date, the successful treatment remains a mainly clinical challenge, it is imperative to develop successful therapeutic agents.
Methods: The anti-proliferative effect of ivermectin on ESCC is investigated in cell model and in nude mice model. Cell apoptosis was assessed using flow cytometry, TUNEL assay and western blotting. Mitochondrial dysfunction was determined by reactive oxygen species accumulation, mitochondrial membrane potential and ATP levels.
Results: Our results determined that ivermectin significantly inhibited the proliferation of ESCC cells in vitro and in vivo. Furthermore, we found that ivermectin markedly mediated mitochondrial dysfunction and induced apoptosis of ESCC cells, which indicated the anti-proliferative effect of ivermectin on ESCC cells was implicated in mitochondrial apoptotic pathway. Mechanistically, ivermectin significantly triggered ROS accumulation and inhibited the activation of NF-κB signaling pathway and increased the ratio of Bax/Bcl-2.
Conclusions: These finding indicated that ivermectin has significant anti-tumour potential for ESSC and may be a potential therapeutic candidate against ESCC
CALYPSO: a method for crystal structure prediction
We have developed a software package CALYPSO (Crystal structure AnaLYsis by
Particle Swarm Optimization) to predict the energetically stable/metastable
crystal structures of materials at given chemical compositions and external
conditions (e.g., pressure). The CALYPSO method is based on several major
techniques (e.g. particle-swarm optimization algorithm, symmetry constraints on
structural generation, bond characterization matrix on elimination of similar
structures, partial random structures per generation on enhancing structural
diversity, and penalty function, etc) for global structural minimization from
scratch. All of these techniques have been demonstrated to be critical to the
prediction of global stable structure. We have implemented these techniques
into the CALYPSO code. Testing of the code on many known and unknown systems
shows high efficiency and high successful rate of this CALYPSO method [Wang et
al., Phys. Rev. B 82 (2010) 094116][1]. In this paper, we focus on descriptions
of the implementation of CALYPSO code and why it works.Comment: accepted in Computer Physics Communication
Prevalence and Characterization of Staphylococcus aureus Isolated From Women and Children in Guangzhou, China
The prevalent Staphylococcus aureus clones and antibiotic susceptibility profiles are known to change dynamically and geographically; however, recent S. aureus strains causing infections in women and children in China have not been characterized. In this study, we analyzed the molecular epidemiology and antimicrobial resistance of S. aureus isolated from patients in four centers for women and children in Guangzhou, China. In total, 131 S. aureus isolates (100 from children and 31 from women) were analyzed by spa typing, multi-locus sequence typing, virulence gene and antimicrobial resistance profiling, staphylococcal chromosomal cassette mec typing, and mutation analyses of rpoB. A total of 58 spa types, 27 sequence types (STs), and 10 clonal complexes (CCs) were identified. While CC59 (ST59-IV, 48.8%; ST338-III, 35.7%) and CC45 (ST45-IV, 100%) were the major clones (84.4%) among MRSA isolates, CC5 (ST188, 24.3%; ST1, 21.6%) and CC398 (ST398, 70%) were the major ones (70.1%) among MSSA isolates. ST338-MRSA-III mostly found in pus but hardly in respiratory tract samples while ST45-MRSA-IV was on the opposite, even though they both found in blood and cerebrospinal fluid sample frequently. Staphylococcal enterotoxin genes seb-seq-sek were strongly associated with ST59 and ST338, while sec was associated with ST45, ST121, ST22, and ST30. All ST338, ST1232, and SCCmec III isolates carried lukF/S-PV genes. A total of 80% of ST338 isolates were resistant to erythromycin, clindamycin, and tetracycline. All ST45 isolates exhibited intermediate or complete resistance to rifampicin. In total, 481 HIS/ASN mutations in rpoB were found in rifampicin-resistant or intermediate-resistant isolates. ST338-III and ST45-IV emerged as two of three major clones in MRSA isolates from women and children in Guangzhou, China, though ST59-MRSA-IV remained the most prevalent MRSA clone. Clonal distribution of S. aureus varied, depending on the specimen source. Virulence genes and antibiograms were closely associated with the clonal lineage. These results clarified the molecular epidemiology of S. aureus from women and children in Guangzhou, China, and provide critical information for the control and treatment of S. aureus infections
Meta-analysis of radiofrequency ablation versus hepatic resection for small hepatocellular carcinoma
<p>Abstract</p> <p>Background</p> <p>There is no clear consensus on the better therapy [radiofrequency ablation (RFA) versus hepatic resection (HR)] for small hepatocellular carcinoma (HCC) eligible for surgical treatments. This study is a meta-analysis of the available evidence.</p> <p>Methods</p> <p>Systematic review and meta-analysis of trials comparing RFA with HR for small HCC published from 1997 to 2009 in PubMed and Medline. Pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model.</p> <p>Results</p> <p>One randomized controlled trial, and 9 nonrandomized controlled trials studies were included in this analysis. These studies included a total of 1411 patients: 744 treated with RFA and 667 treated with HR. The overall survival was significantly higher in patients treated with HR than in those treated with RFA at 3 years (OR: 0.56, 95% CI: 0.44-0.71), and at 5 year (OR: 0.60, 95% CI: 0.36-1.01). RFA has a higher rates of local intrahepatic recurrence compared to HR (OR: 4.50, 95% CI: 2.45-8.27). In the HR group the 1, 3, and 5 years disease -free survival rates were significantly better than in the HR-treated patients (respectively: OR: 0.54, 95% CI: 0.35-0.84; OR: 0.44, 95% CI: 0.28-0.68; OR: 0.64, 95% CI: 0.42-0.99). The postoperative morbidity was higher with HR (OR: 0.29, 95% CI: 0.13-0.65), but no significant differences were found concerning mortality. For tumors ≤ 3 cm HR did not differ significantly from RFA for survival, as reported in three NRCTs .</p> <p>Conclusions</p> <p>HR was superior to RFA in the treatment of patients with small HCC eligible for surgical treatments, particularly for tumors > 3 cm. However, the findings have to be carefully interpreted due to the lower level of evidence.</p
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Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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