Prototype Design and Feasibility Analysis for Self-Levitated Conveying

In order to avoid friction and scratching when conveying object, an acoustic levitation prototype was designed to verify the feasibility. The modal shapes and the forced harmonic shapes of the prototype are obtained by an ANSYS coupled field computation with a one-quarter symmetry model and the levitation capacity was assessed by the use of groups of simulation and physical testing. The simulation results showed that the pure flexural and mixed flexural wave shapes with different wave numbers existed at some specific frequency. The amplitude in the central point of an aluminum plate having four piezo-electric discs glued to the bottom surface was simulated for a frequency spectrum. The experimental results confirmed the theoretical results and the feasibility of the prototype and confirm that objects can be floated at several resonant frequencies under forced vibrating condition. The system can provide largest bearing capacity when both the piezoelectric disc and the plate resonances coincide

Active force control of structure-borne sound based on robust optimization subjected to an irregular cavity with uncertainties

This paper proposes a novel method of structure-borne sound analysis and active force control, which combines interval mathematics and robust optimization theorems, to achieve vibration damping and noise reduction for enclosed cavity systems with bounded uncertainty. By introducing the interference principle of sound wave, responses under control can be obtained by solving finite element equations of structural–acoustic coupling systems. Through synthetical considerations of parameter dispersion in practice, the interval quantitative model, which only needs limited sample data, is defined, and the interval Taylor extension approach is employed to further determine boundary rules of responses of structural vibration and acoustic noise. On this basis, a new interval-oriented robust optimization framework is established to seek the optimal secondary force to simultaneously minimize nominal and radius levels of sound pressure indexes at concerned space and frequency domains. A complicated engineering example of the 3-D bomb cavity is eventually presented, in which numerical and experimental results can demonstrate the usage, validity and effectiveness of the developed methodology

Protective role of deoxyschizandrin and schisantherin A against myocardial ischemia-reperfusion injury in rats.

BackgroundOur previous studies suggested that deoxyschizandrin (DSD) and schisantherin A (STA) may have cardioprotective effects, but information in this regard is lacking. Therefore, we explored the protective role of DSD and STA in myocardial ischemia-reperfusion (I/R) injury.Methodology/principal findingsAnesthetized male rats were treated once with DSD and STA (each 40 µmol/kg) through the tail vein after 45 min of ischemia, followed by 2-h reperfusion. Cardiac function, infarct size, biochemical markers, histopathology and apoptosis were measured and mRNA expression of gp91 (phox) in myocardial tissue assessed by RT-PCR. Neonatal rat cardiomyocytes were pretreated with DSD and STA and then damaged by H2O2. Cell apoptosis was tested by a flow cytometric assay. Compared with the I/R group: (i) DSD and STA could significantly reduce the abnormalities of LVSP, LVEDP, ±dp/dtmax and arrhythmias, thereby showing their protective roles in cardiac function; (ii) DSD and STA could significantly attenuate the infarct size and MDA release while increasing SOD activity, suggesting a role in reducing myocardial injury; (iii) tissue morphology and myocardial textual analysis revealed that DSD and STA mitigated changes in myocardial histopathology; (iv) DSD and STA decreased apoptosis (33.56±2.58% to 10.28±2.80% and 10.98±1.99%, respectively) and caspase-3 activity in the myocardium (0.62±0.02 OD/mg to 0.38±0.02 OD/mg and 0.32±0.02 OD/mg, respectively), showing their protective effects upon cardiomyocytes; and (v) DSD and STA had similar protective effects on I/R injury as those seen with the positive control metoprolol. In vitro, DSD and STA could significantly decrease the apoptosis of neonatal cardiomyocytes.Conclusions/significanceThese data suggest that DSD and STA can protect against myocardial I/R injury. The underlining mechanism may be related to their role in inhibiting cardiomyocyte apoptosis

Longitudinal Association between Physical Activity, Blood Lipids, and Risk of Dyslipidemia among Chinese Adults: Findings from the China Health and Nutrition Surveys in 2009 and 2015

Physical activity is needed in today’s highly sedentary society. Research into Chinese trends with respect to the longitudinal association between changes in physical activity (PA) and dyslipidemia (DL) is limited. The present study assessed PA and PA-related changes associated with the level of serum lipids, and the risk of dyslipidemia stratified by gender, via a population-based longitudinal observational study among adults (>18 years old) residing in nine provinces in China. Data of 3380 adult participants, gleaned from two surveys in 2009 and 2015 used by the China Health and Nutrition Survey (CHNS), were analyzed. Three-level random intercept growth models were used to calculate the associations between total physical activity (TPA), the four activity subtypes, and changes in the level of blood lipids. Three-level logistic regression models were utilized to assess the association between TPA and the risk of DL. The highest level of TPA was observed to correlate with the lowest prevalence of DL. Compared with the lowest level of TPA, the highest level of TPA increases the concentration of HDL-C (β = 0.050, 95% CI = 0.005, 0.096) in males, and also reduces the risk in males of having low HDL-C by 31% (OR = 0.69, 95% CI = 0.52, 0.91). Occupational PA was positively associated with higher HDL-C levels in both genders (males: β = 0.004, 95% CI = 0.002, 0.007; females: β = 0.002, 95% CI = 0.000, 0.004), and leisure-time physical activity (LTPA) was negatively associated with TG levels in males. Increasing TPA benefited HDL-C levels in males, irrespective of the level of basic TPA of individuals. Physical activity (especially occupational PA) was superior in positively influencing HDL-C in males, but not in females. Leisure-time physical activity needs to be increased substantially in order to increase TPA to levels that would be beneficial to blood lipid levels and DL, irrespective of baseline TPA levels

Effects of various administrations upon hemodynamics in a model of ischemia–reperfusion in rats.

<p>Data are the mean ± SD. Values marked with ^&&<i>P</i><0.01 are significantly different from I/R. Values marked with * <i>P</i><0.05 or ** <i>P</i><0.01 are significantly different from metoprolol. Values marked with ^†<i>P</i><0.05 or ^‡<i>P</i><0.01 are significantly different from baseline. LVSP, LVEDP and ± d<i>p</i>/dt_max represent left ventricular systolic pressure, left ventricular end-diastolic pressure, and the maximal rates of increase and decrease in LV pressure, respectively.</p

Examples of ventricular tachycardia (VT) and ventricular fibrillation (VF).

<p>A shows sustained VT of regular morphology and rate. B shows one example of terminal VF. Scale bar, 300 ms.</p

Effect on serum MDA levels and SOD activity after I/R injury in each group of rats.

<p>Serum samples were collected after 2 h of reperfusion; MDA concentrations were assayed according to the thiobarbituric acid (TBA) method (A); SOD activities were measured by the xanthine oxidase method (B). Traces of the mean values (± SD, vertical lines). ^&&<i>P</i><0.01 <i>vs</i> I/R, ^**<i>P</i><0.01 <i>vs</i> metoprolol.</p

Infarct size in rats of various groups subjected to I/R injury.

<p>Representative illustrations of infarct size as stained by Evans Blue and TTC (A). Bar graphs show AAR as a percentage of the LV (B) and An as a percentage of the AAR (C). Traces of the mean values (± SD, vertical lines). ^&&<i>P</i><0.01 <i>vs</i> I/R, ^**<i>P</i><0.01 <i>vs</i> metoprolol.</p

Effects of various administrations on gray level co-occurrence matrix parameters in a model of ischemia–reperfusion in rats.

<p>Data are the mean ± SD. Values marked with ^&<i>P</i><0.05 or ^&&<i>P</i><0.01 are significantly different from I/R. Values marked with * <i>P</i><0.05 or ** <i>P</i><0.01 are significantly different from metoprolol. ASM, CT, CR, IDM and ET represent angular second moment, contrast, correlation, inverse difference moment and entropy, respectively.</p