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A new approach for evaluating the flutter instability boundaries based on the analytical solution of the equation of motion of cantilever pipes conveying fluid has been attempted. This approach leads to a simple transcendental equations form which the critical speed of flutter instability and the associated natural frequencies of cantilever pipes can be determined for any pipe parameters. The stability and critical natural frequencies maps can be simply constructed. The results of the presented approach are carefully checked with published results. The presented results showed very good agreements. [ABSTRACT FROM AUTHOR]

The dynamical behaviors of pipes containing pulsating fluids are nonlinear. In such nonlinear systems principal regions of dynamical instability can result from the effect of the periodic excitation of the fluctuated fluid flow. Evaluating the boundary frequencies for these types of instabilities had been carried out by many analytical and numerical methods. In this paper, an approximate "closed-form" solution for evaluating the principal boundary regions of instability for conservative pipes conveying pulsated fluid has been attempted. Bolotin's method was employed to split the boundaries from the stable regions. The resulting coupled-ordinary differential equations is decoupled by neglecting the effect of the mass ratio term and solved analytically. After imposing the specified boundary conditions, then the simplified formulas or transcendental equations were obtained for the pipes under consideration. These equations can give the principal boundary regions in term of the system parameters by simple calculations. The present solution was carefully checked with the "exact" solution where the mass ratio was included. The results showed good agreement for pinned-pinned clamped-pinned and clamped-clamped pipes conveying pulsating fluid. [ABSTRACT FROM AUTHOR]

Background: The National Institutes of Health Stroke Scale or NIH Stroke Scale (NIHSS) is a widely used tool for assessing stroke severity. We conducted this study to determine the severity of stroke patients admitted in a tertiary care hospital. Methods: This is a cross sectional study conducted in Department of Neurology, Dhaka Medical College Hospital from April 2016 to October 2016 involving 91 acute stroke patients. Result: About half (44%) of the patients were older than 60 years of age and mean age of the patients was 60.34 (± 16.1) years at onset and there is a slight female predominance (51.6%). Majority had hypertension (75.8%) followed by physical inactivity (67%), diabetes (37.4%), smoking (33%), obesity (23.1%), family H/O stroke (20.9%) and dyslipideamia (15.4%). Many patients were found to have hyperglycemia (14.3%) followed by hyperthermia (13.2%), hypotension (4.4%) and low oxygen saturation (3.3%) at the time of admission. Most of them had ischemic stroke (60%), followed by intracerebral hemorrhage (35%) and subarachnoid hemorrhage (5%). After leveling with NIHSS score more than half of the patients (51%) were found to be moderate grade on admission. Although, there was no association between risk factors of stroke and admission NIHSS score level, significant association was found between hypoxia and admission NIHSS score severity. Conclusion: Acute stroke patients, mostly have moderate grade of NIHSS score on admission. Hypertension, physical inactivity, diabetes, smoking, obesity, family H/O stroke and dyslipideamia are common risk factors observed among the patients which have no significant association with admission stroke severity determined by NIHSS score. There is significant association between hypoxia and admission NIHSS score severity. [ABSTRACT FROM AUTHOR]

Aims The development of wire mesh collimator (WMC), has improved the performance of Single Photon Emission Computed tomography (SPECT) because of its higher sensitivity whilst maintaining the same resolution. Consequently, the WMC allows better detection of early-stage cancer. The purpose of this study was to find an optimal filter for image reconstruction for breast SPECT imaging. Methods Half-ellipsoidal breast phantom in the prone position was simulated with dual-head SPECT camera by Monte Carlo N-Particle Transport Code, version 5 (MCNP5). Six different filters were compared with 17 different cutoff frequencies (Fc), ranging from 0.2 Nyquist frequency (Nq) to 1.0 Nq, with step 0.05. For Butterworth filter, order was from 3 to 12 with step 1. A total of 255 central slices with different parameters were reconstructed by filtered back projection (FBP) to compare the image performance in terms of contrast, noise level and tumour size. Results The values of tumour size, contrast and noise level were greatly influenced by different filter types and the value of Fc. Ramp and Butterworth produced the best value of tumour size and contrast, whilst Parzen, Hann and Hamming filters gave smoother images. Overall, results showed that Butterworth filter with the highest mean score. Conclusion Butterworth filter proved to be the provided the best image quality at a higher sensitivity and was found to be the optimum filter for quantitative analysis. [ABSTRACT FROM AUTHOR]

Euphorbia hirta(L.) plant is traditionally used in Malaysia for the treatment of gastrointestinal, bronchial and respiratory ailments caused by nosocomial infectious agents. Bioactivity-guided fractionation of the methanol extract of the aerial parts ofE. hirtaand analysis using high-performance liquid chromatography have led to the isolation of two antibacterial compounds. These compounds were identified as caffeic acid (CA) and (–)-epicatechin 3-gallate (ECG) based on spectroscopic analyses and comparison with previously published data. Using broth microdilution method, both ECG and CA had demonstrated significant minimum inhibitory concentration of 15.6  and 31.3 μg/mL respectively, againstPseudomonas aeruginosa. Time-kill assessment of ECG and CA displayed bactericidal effect onP. aeruginosacells. [ABSTRACT FROM PUBLISHER]

Objective: The purpose of this study was to retrospectively evaluate the sensitivity, specificity and accuracy of identifying methamphetamine (MA) internal payloads in "drug mules" by plain abdominal digital radiography (DR). Methods: The study consisted of 35 individuals suspected of internal MA drug containers. A total of 59 supine digital radiographs were collected. An overall calculation regarding the diagnostic accuracy for all "drug mules" and a specific evaluation concerning the radiological appearance of drug packs as well as the rate of clearance and complications in correlation with the reader's experience were performed. The gold standard was the presence of secured drug packs in the faeces. Results: There were 16 true-positive "drug mules" identified. DR of all drug carriers for Group 1 (forensic imaging experienced readers, n = 2) exhibited a sensitivity of 100%, a mean specificity of 76.3%, positive predictive value (PPV) of 78.5%, negative predictive value (NPV) of 100% and a mean accuracy 87.2%. Group 2 (inexperienced readers, n = 3) showed a lower sensitivity (93.7%), a mean specificity of 86%, a PPV of 86.5%, an NPV of 94.1% and a mean accuracy of 89.5%. The interrater agreement within Group 1 was 0.72 and within Group 2 averaged to 0.79, indicating a fair to very good agreement. Conclusion: DR is a valuable screening tool in cases of MA body packers with huge internal payloads being associated with a high diagnostic insecurity. Diagnostic insecurity on plain films may be overcome by low-dose CT as a cross-sectional imaging modality and addressed by improved radiological education in reporting drug carriers on imaging. Advances in knowledge: Diagnostic signs (double-condom and halo signs) on digital plain radiography are specific in MA "drug mules", although DR is associated with high diagnostic insecurity and underreports the total internal payload. [ABSTRACT FROM AUTHOR]