Proton magnetic resonance spectroscopy of brain in obstructive sleep apnea in Egyptian subjects

AbstractObjectiveThe overall objective of this work is to study the cerebral metabolic changes in patients with OSA and to determine the usefulness of MRS as an objective method for evaluation of CNS impairment in these patients.Materials and methodsThis study included two groups; group1 fifteen (15) patients diagnosed with obstructive sleep apnea hypopnea syndrome, and group 2 ten (10) healthy volunteers of comparable age.Magnetic resonance spectra were obtained from frontal periventricular white matter.For all subjects, height, body weight, and BMI were assessed. Waist and hip circumference were measured and waist/hip ratio (W/H ratio) was calculated.Overnight polysomnography (PSG) to identify sleep apnea was done. Daytime sleepiness was evaluated by the Epworth Sleepiness Scale. Symptoms of anxiety and depression were measured with the Hospital Anxiety and Depression Scale (HADS).ResultsN-acetylaspartate-to-creatine (NAA/Cr) and choline-to-creatine (Cho/Cr) ratios were significantly lower in the frontal white matter of obstructive sleep apnea patients when compared to controls. Absolute concentrations of N-acetylaspartate (NAA) and choline (Cho) were also significantly reduced in the frontal white matter of patients with sleep apnea. Statistically significant negative correlations existed between AHI and metabolites concentrations and ratios in patients with OSAHS. Significant positive correlations existed in patients with OSAHS between Hospital and depression scale for depression (HAD-D) and AHI (r=0.764, p=0.001), ODI (r=0.571, p=0.026), and ESS (r=0.644, p=0.010), respectively. Significant positive correlations existed in patients with OSAHS between Hospital and depression scale for anxiety (HAD-A) and AHI (r=0.753, p=0.001), and ESS (r=0.537, p=0.039), respectively. Multivariate Linear regression model of factors predictive showed AHI as the main predictor factor for choline to creatine ratio in patients with OSAHS with t=5.180, at p<0.001.ConclusionOSA patients show abnormal brain metabolites related to neuronal damage due to intermittent chronic hypoxemia. Anxious and depressive symptoms are highly prevalent in patients with severe untreated OSAS. The severity of depressive and anxious symptoms may be related to excessive daytime sleepiness and to nocturnal hypoxemia both of which are strongly correlated to brain metabolites. AHI seems to be the main predictor factor for choline to creatine ratio in patients with OSAHS

Transition Experiments on Blunt Bodies with Isolated Roughness Elements in Hypersonic Free Flight

Smooth titanium hemispheres with isolated three-dimensional (3D) surface roughness elements were flown in the NASA Ames hypersonic ballistic range through quiescent CO2 and air environments. Global surface intensity (temperature) distributions were optically measured and thermal wakes behind individual roughness elements were analyzed to define tripping effectiveness. Real-gas Navier-Stokes calculations of model flowfields, including laminar boundary layer development in these flowfields, were conducted predict key dimensionless parameters used to correlate transition on blunt bodies in hypersonic flow. For isolated roughness elements totally immersed within the laminar boundary layer, critical roughness Reynolds numbers for flights in air were found to be higher than those measured for flights in CO2, i.e., it was easier to trip the CO2 boundary layer to turbulence. Tripping effectiveness was found to be dependent on trip location within the subsonic region of the blunt body flowfield, with effective tripping being most difficult to achieve for elements positioned closest to the stagnation point. Direct comparisons of critical roughness Reynolds numbers for 3D isolated versus 3D distributed roughness elements for flights in air showed that distributed roughness patterns were significantly more effective at tripping the blunt body laminar boundary layer to turbulence

Pengaruh Keefektifan Pengendalian Internal, Kesesuaian Kompensasi, Moralitas Aparat dan Asimetri Informasi terhadap Kecenderungan Kecurangan Akuntansi

This study aims to examine the effect of Influence Effectiveness of Internal Control, Compliance Compensation, Morality Apparatus and Information Asymmetry on Accounting Fraud Trends. This research was conducted by using descriptive method survey. Collecting data in this study are primary data obtained from questionnaires distributed directly to the respondents. Sample selection technique is purposive sampling. The sample used in this study were 61 respondents who served as the fourth echelon in the regional work units (SKPD) in Siak Sri Indrapura. Management and analysis of data using multiple linear regression analysis with the help of software SPSS version 20 (Statistical Product and Service Solution). Hypothesis testing results indicate that effectiveness of internal control, suitability of the compensation and apparatus morality negative effect on the tendency of accounting fraud and information asymmetry positive effect on the tendency of accounting fraud. The coefficient of determination in this study was 62.2%, while 37.8% is influenced by other variables.Keywords: Internal Control, Compensation, Morality, Information and Accounting Frau

Transition Experiments on Blunt Bodies with Distributed Roughness in Hypersonic Free Flight in Carbon Dioxide

Blunt-body geometries were flown through carbon dioxide in the NASA Ames Hypervelocity Free Flight Aerodynamic Facility to investigate the influence of distributed surface roughness on transition to turbulence in CO2-dominated atmospheres, such as those of Mars and Venus. Tests were also performed in air for direct comparison with archival results. Models of hemispherical and spherically-blunted large-angle conical geometries were flown at speeds between 2.8 km/s and 5.1 km/s and freestream pressures between 50 Torr and 228 Torr. Transition fronts were determined from global surface heat flux distributions measured using thermal imaging techniques. Distributed surface roughness was produced by grit-blasting the model surfaces. Real-gas Navier-Stokes solutions were used to calculate non-dimensional correlating parameters at the measured transition onset locations. Transition-onset locations correlated well with a constant roughness Reynolds number based on the mean roughness element height. The critical roughness Reynolds number for transition onset determined for flight in CO2 was 223 +/- 25%. This mean value is lower than the critical value of 250 +/- 20% previously-established from tests conducted in air, but within the bounds of the expected measurement uncertainty

Effect of energy window width on planer and SPECT image uniformity

AbstractTo detect radiopharmaceutical distribution in patient organs and avoid interpretation mistakes, due to the protocol errors, a gamma camera must work in optimum conditions. One such error is camera non-uniformity. Baron and Chouraqui[Baron, J.M., Chouraqui, P., 1996. Myocardial single-photon emission computed tomographic quality assurance. J. Nucl. Cordial. 3(2), 157–166] have reported the need to ensure consistently high image quality and accuracy using an optimally chosen standardized protocol. It has been reported that single photon emission computed tomography (SPECT) significantly improved contrast over the planer image and has the ability to separate overlapping structures[Critchly, M., 1993. Nuclear Medicine Pocket Handbook, Amersham International Plc, pp. 6–7]. Window width of energy is considered as one of the most important physical parameters affecting the quality of planer and SPECT images. Thus, the effect of widow widths of energy 5%, 10%, 15%, 20% and 25% on planer and SPECT images were investigated using a Tc-99m source at 140keV. Tc-99m is the most common isotope in nuclear medicine and has one well-defined peakT in comparison with thallium, which has three peaks. In the present study, it was evident that energy window width played a prominent role in flood images uniformity using the Tc-99m source. The calculated integral uniformity percentage (IU%) and differential uniformity percentage (DU%) values of center field of view (CFOV) and useful field of view (UFOV) were markedly changed with a change of energy window width. The optimum energy window width was in the range from 15% to 20%. Moreover, the effect of window widths of energy 5%, 10%, 15%, 20% and 25% on SPECT image on a heart phantom with an artificial defect performed at the anterior wall of the heart was investigated. The SPECT images were clinically examined by a physician who reported a different diagnosis for each energy window width due to vertical long axis cuts, which, in turn, were due to the change in the collected counts. We concluded that the optimum energy window width was also in the range 15–20% for the Tc-99m isotope, which confirmed previous planer results

Synthesis of New Coumarin Derivatives Used as Nitrification Inhibitors to Mitigation of Nitrous Oxide Emission from Agricultural Soil.

Nitrous oxide (N2O) is one of the major greenhouse gases "GHG” the main source of N2O emission is synthetic mineral nitrogen fertilizers. The conversion values according to the global warming potential for N2O are 298 times as CO2 per molecule. The main objective of this work is to mitigate GHG emission from N2O by create synthesis new nitrification inhibitors.  Coumarine derivatives were synthesized (1-4), and prove the structures by spectral data, the compounds (1) and (4) were applied as nitrification inhibitors to mitigation of nitrous oxide. The results indicated that, the presence of each of the two tested inhibitors (1, 4) reduced the N2O emission from urea-treated soils by 72% and 49%, respectively, in inhibiting nitrification during the 28-day incubation period. Key words: Nitrous oxide emissions, Mitigation, Agricultural soil, Nitrification, Coumarin derivatives

Empirically modelled Pc3 activity based on solar wind parameters

It is known that under certain solar wind (SW)/interplanetary magnetic field (IMF) conditions (e.g. high SW speed, low cone angle) the occurrence of ground-level Pc3–4 pulsations is more likely. In this paper we demonstrate that in the event of anomalously low SW particle density, Pc3 activity is extremely low regardless of otherwise favourable SW speed and cone angle. We re-investigate the SW control of Pc3 pulsation activity through a statistical analysis and two empirical models with emphasis on the influence of SW density on Pc3 activity. We utilise SW and IMF measurements from the OMNI project and ground-based magnetometer measurements from the MM100 array to relate SW and IMF measurements to the occurrence of Pc3 activity. Multiple linear regression and artificial neural network models are used in iterative processes in order to identify sets of SW-based input parameters, which optimally reproduce a set of Pc3 activity data. The inclusion of SW density in the parameter set significantly improves the models. Not only the density itself, but other density related parameters, such as the dynamic pressure of the SW, or the standoff distance of the magnetopause work equally well in the model. The disappearance of Pc3s during low-density events can have at least four reasons according to the existing upstream wave theory: 1. Pausing the ion-cyclotron resonance that generates the upstream ultra low frequency waves in the absence of protons, 2. Weakening of the bow shock that implies less efficient reflection, 3. The SW becomes sub-Alfvénic and hence it is not able to sweep back the waves propagating upstream with the Alfvén-speed, and 4. The increase of the standoff distance of the magnetopause (and of the bow shock). Although the models cannot account for the lack of Pc3s during intervals when the SW density is extremely low, the resulting sets of optimal model inputs support the generation of mid latitude Pc3 activity predominantly through upstream waves