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The study analyzed the acoustical absorption performance of wooden perforated panels with finite element analysis software-ANSYS. The research process include modeling, meshing, loads, solution and results display. Simulation results showed that software ANSYS was good at absorption performance analysis of wooden perforated panels. There are some pressure distribution zones with peak and valley alternation between speaker and the tested material of the built model. It coincides with test result of real experiment equipment. The selections of structural parameters of wooden perforated panel lead to changes for solution. [ABSTRACT FROM AUTHOR]

Backgrounds: Intracranial atherosclerosis is the commonest vascular lesion for ischemic stroke in Asians. Most research on risk factors for middle cerebral artery (MCA) stenosis has been conducted in symptomatic patients with ischemic stroke or transient ischemic attack. The present study aimed to investigate risk factors for MCA stenosis in an asymptomatic population in Rongqi County in Southern China. Methods: We assessed 1,068 asymptomatic subjects over 50 years of age by transcranial Doppler. Medical history documentation and investigation of biochemical markers were performed for each subject. Multivariant, unconditioned, logistic regression analyses were employed to assess the risk factors associated with MCA stenosis. Results: MCA stenosis was found in 63 subjects (5.9%). Male gender, advancing age, hypertension, diabetes and systolic blood pressure were significant risk factors for MCA stenosis (p < 0.001). Based on logistic regression analyses, 4 factors emerged as independent risk factors (p < 0.001) of MCA stenosis: male gender [95% confidence interval (CI) = 1.49–4.66, OR = 2.63], age (95% CI = 1.01–1.06, OR = 1.04), hypertension (95% CI = 4.57–18.35, OR = 9.16) and diabetes mellitus (95% CI = 3.09–11.29, OR = 5.9). Conclusion: MCA stenosis is relatively common among asymptomatic Chinese subjects. Male gender, advanced age, hypertension and diabetes mellitus are risk factors for MCA stenosis. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Hyperhomocysteinemia (HHcy) is considered to be an independent risk factor for atherosclerosis. We aimed to determine the relation between Hcy and cerebral artery stenosis in a large Chinese population. We present data concerning 2,500 residents. Plasma was saved from 1,020 residents who were asymptomatic. Hcy concentration was measured by fluorescence ration biochemical assay kit, and middle cerebral artery (MCA) was assessed by Transcranial Doppler in these subjects. Fifty-six residents with MCA stenosis were included in this study. The remained 964 residents without stenosis were control. Analysis of the data revealed that the plasma concentration of Hcy (18.33 ± 5.34 µmol/L), age (63.9 ± 12.9) and systolic pressure (142.6 ± 22.6 mmHg) in the stenotic group were increased (p < 0.0001) compared with the control group (Hcy12.95 ± 4.57 µmol/L, age 55.8 ± 10.9, systolic pressure 126.3 ± 20.3 mmHg). Based on logistic regression, 5 factors emerged as independent predictors of MCA stenosis: Hcy (OR = 1.16, 95%confidence interval 1.14–1.26), male (OR = 2.63, 95%CI 1.49–4.66), age (OR = 1.04, 95%CI 1.01–1.07), hypertension (OR = 9.16, 95%CI 4.57–18.35), diabetes mellitus (OR = 5.90, 95%CI 3.09–11.29). Hyperhomocysteinemia might be one of the risk factors for cerebral artery stenosis. It may play a role in atherosclerosis and thrombosis. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE Current criteria for middle cerebral artery (MCA) stenosis by transcranial Doppler were mainly based on the flow velocity acceleration, ignoring other useful parameters. We tested the accuracy of new criteria using magnetic resonance angiography (MRA) as the confirmative method. METHODS A compositive score for each MCA was calculated according to following parameters: Velocity Scale (score 0-6 for peak systolic velocity <140 to ≥300 cm/second), Hemodynamic Scale (score 0-5 for diffuse or focal velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), and Spectrum Scale (score 0-2 for normal spectrum, turbulence, and musical murmurs). RESULTS The median scores in normal-mild, moderate, and severe groups on MRA differed significantly ( P < .001). The optimal cutoff score for <50% and ≥50% stenosis was 3 with the PPV of 72.3% (95% confidence interval [CI]: 65.3% to 78.5%) and negative predictive value (NPV) of 89.5% (95% CI: 85.9% to 92.3%), for moderate and severe stenosis was 6 with the PPV of 85.9% (95% CI: 76.7% to 92.0%) and NPV of 61.9% (95% CI: 50.6% to 72.1%). Both scores performed better than peak systolic or mean velocity. CONCLUSIONS This new method was feasible and reliable and showed some advantages over the velocity-only method. Further studies using digital subtraction angiography as the gold standard are needed to ameliorate the new criteria. [ABSTRACT FROM AUTHOR]