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The design and fatigue strength of a nitinol iliac vein stent (NIVS) proposed in this study are assessed using the finite element analysis method. The influence of stent diameter and different release scales on its strength, lifespan and biomechanical properties of the vein wall is analyzed for self-developed NIVS of three different diameters (12, 14 and 16mm) and length of 26mm, which were implanted into the corresponding iliac vein with different release scales (80% and 90%). The results obtained strongly indicate that with an increase in the release scale, the equivalent elastic strain, safety factors of fatigue strength, and equivalent stress of the vessel wall exhibit a downward trend, while the most stressed cross-section coincides with the arc of stent-connecting rods. The efficiency and safety of the above stents were verified by in vivo tests (with observation periods of 30, 90 and 180 days after operation) on ten lab pigs, which underwent NIVS implantation into the iliac veins, with observation of hemodynamics, stent deployment, presence/absence of thrombosis, and monitoring of stent lumen loss and its rate. During the animal test verification, the stent release was satisfactory, while the radiography revealed no obvious stent displacement at different time points. In addition, the patency rate of the stent was 100%. Except for the control group, where a small amount of old thrombus was found, other stents exhibited no thrombus; at the same time, there was no significant difference in the lumen loss rate of the stent at each time point. Therefore, the proposed nitinol NIVS samples demonstrated a good performance, accurate positioning, and release, in addition to the reduced risk of lateral iliac vein thrombosis. [ABSTRACT FROM AUTHOR]

In this article, procedure and efficiency of the reduced-basis approach in structural design computation are studied. As a model order reduction approach, it provides fast evaluation of a structural system in explicitly parameterized formulation. Theoretically, the original structural system is reduced to obtain a reduced system by being projected onto a lower dimensional subspace. However, in practice, it is a time-consuming process due to the iterations of adaptive procedure in subspace construction. To improve the efficiency of the method, some characteristics are analyzed. First, the accuracy of the subspace is evaluated and computational costs of procedures with different approaches are studied. Results show that the subspaces constructed by greedy adaptive procedures with different beginnings have the same accuracy. It is instructive that accuracy of the subspace is guaranteed by adaptive procedure. And the computational costs depend on the number of iterations in adaptive procedure. Thus, a modified adaptive procedure is proposed to reduce the computational costs and guarantee the accuracy. The modified adaptive procedure begins with experimental design methods to obtain a set of samples rather than a single sample and ends with the adaptive procedure. The start set of samples are selected by the following experimental design methods: 2k factorial design, standard Latin design and Latin hypercube design. By being integrated with the experimental design, the modified adaptive procedure saves computational costs and retains the same accuracy as traditional procedure does. As an example, the outputs of a vehicle body front compartment subjected to a bending load are illustrated. It is proved that the proposed procedure is efficient and is applicable to many other structural design contexts. [ABSTRACT FROM PUBLISHER]

BACKGROUND: Observational studies from Asia suggest that maxingshigan-yinqiaosan may be effective in the treatment of acute H1N1 influenza. OBJECTIVE: To compare the efficacy and safety of oseltamivir and maxingshigan-yinqiaosan in treating uncomplicated H1N1 influenza. DESIGN: Prospective, nonblinded, randomized, controlled trial. (ClinicalTrials.gov registration number: NCT00935194) SETTING: Eleven hospitals from 4 provinces in China. PATIENTS: 410 young adults aged 15 to 59 years with laboratory-confirmed H1N1 influenza. INTERVENTION: Oseltamivir, 75 mg twice daily; maxingshigan-yinqiaosan decoction (composed of 12 Chinese herbal medicines, including honey-fried Herba Ephedrae), 200 mL 4 times daily; oseltamivir plus maxingshigan-yinqiaosan; or no intervention (control). Interventions and control were given for 5 days. MEASUREMENTS: Primary outcome was time to fever resolution. Secondary outcomes included symptom scores and viral shedding determined by using real-time reverse transcriptase polymerase chain reaction. RESULTS: Significant reductions in the estimated median time to fever resolution compared with the control group (26.0 hours [95% CI, 24.0 to 33.0 hours]) were seen with oseltamivir (34% [95% CI, 20% to 46%]; P < 0.001), maxingshigan-yinqiaosan (37% [CI, 23% to 49%]; P < 0.001), and oseltamivir plus maxingshigan-yinqiaosan (47% [CI, 35% to 56%]; P < 0.001). Time to fever resolution was reduced by 19% (CI, 0.3% to 34%; P = 0.05) with oseltamivir plus maxingshigan-yinqiaosan compared with oseltamivir. The interventions and control did not differ in terms of decrease in symptom scores (P = 0.38). Two patients who received maxingshigan-yinqiaosan reported nausea and vomiting. LIMITATIONS: Participants were young and had mild H1N1 influenza virus infection. Missing viral data precluded definitive conclusions about viral shedding. CONCLUSION: Oseltamivir and maxingshigan-yinqiaosan, alone and in combination, reduced time to fever resolution in patients with H1N1 influenza virus infection. These data suggest that maxingshigan-yinqiaosan may be used as an alternative treatment of H1N1 influenza virus infection. PRIMARY FUNDING SOURCE: Beijing Science and Technology Project and Beijing Nova Program. [ABSTRACT FROM AUTHOR]