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Search Results: 1 - 10 of 598 matches for " Jafar Vossoughi "
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Effect of Induced Anxiety on Respiratory Resistance Using Virtual Reality Simulation  [PDF]
Matthew Bohensky, Arthur T. Johnson, Jafar Vossoughi
Open Journal of Respiratory Diseases (OJRD) , 2017, DOI: 10.4236/ojrd.2017.72008
Abstract: Background: The purpose of this research was to identify significant changes to respiratory resistance resulting from anxiety inducing simulations presented through the medium of virtual reality (VR) goggles. The tested hypothesis was that a virtual reality simulation would produce anxiety in the wearer, and, with it, a statistically significant change in subject respiratory resistance. It was also suggested that there may be a significant difference in the levels of respiratory resistance responses of males and females. The Oculus Rift DK2 VR goggles with video software designed for the Rift were used to induce anxiety in the wearers. Methods: Respiratory resistances in both inhalation and exhalation directions were measured with the Airflow Perturbation Device (APD), a medical instrument used noninvasively. Two groups of subjects were tested: the test group watched a simulation deemed to be anxiety inducing, and the Control group watched a simulation determined to be non-anxiety inducing. Anxiety levels and respiratory resistance were measured before and during the simulation with two anxiety measures, the State Trait Anxiety Inventory (STAI) and the Subjective Units of Distress Scale (SUDS). Results: Statistically significant increases in anxiety level and respiratory resistance were found in the Test group, but no significant differences in anxiety and respiratory resistance levels were found in the control group. Anxiety affected both breathing phases similarly. For the gender hypothesis, we found that one of the tests used to measure anxiety, (the SUDS difference) was statistically significant, while the other test and the difference in respiratory resistance were not statistically significant. Conclusion: Results from this experiment show that anxiety level can be a significant contributor to the physiological measurement of respiratory resistance, and this can have implications for pulmonary function test environments and the psychological conditions of the patients being tested.
Testing Low Doses of Caffeine on Respiratory Resistance Using the Airflow Perturbation Device  [PDF]
Mary Kate Montgomery, Allen Luk, Arthur T. Johnson, Jafar Vossoughi
Open Journal of Respiratory Diseases (OJRD) , 2017, DOI: 10.4236/ojrd.2017.72006
Abstract: Research reports on pulmonary function measurements often mention caffeine abstinence as a condition for testing subjects. Yet, the effects of caffeine on respiration are not well documented. This study was intended to investigate the physiological effects of caffeine on respiratory resistance measurements and the necessity of caffeine avoidance in such testing. Thirty-one subjects were administered caffeine in pill form for dosages in the range of 3 - 4.5 mg/kg body weight. Respiratory resistance was measured with the Airflow Perturbation Device every 15 minutes after caffeine ingestion until a full hour of elapsed time. No changes were noted in inhalation, exhalation, and average respiratory resistances during the times of measurements. The conclusion is that for low dosages of caffeine, respiratory resistance measurements are not affected by caffeine ingestion prior to testing.
Resistance Measured by Airflow Perturbation Compared with Standard Pulmonary Function Measures  [PDF]
Tania Haque, Jafar Vossoughi, Arthur T. Johnson, Wanda Bell-Farrell, Thomas Fitzgerald, Steven M. Scharf
Open Journal of Respiratory Diseases (OJRD) , 2013, DOI: 10.4236/ojrd.2013.32010
Abstract: Background: Routine lung function testing requires expensive equipment, or requires maximum expiratory effort. The airflow perturbation device (APD) is a light handheld device, allowing for serial measures of respiratory resistance noninvasively and effortlessly. Methods: In a convenience sample of 398 patients undergoing pulmonary function testing, we compared routine spirometric indices (forced expired volume in 1 second (FEV1), peak expiratory flow (PEF)), and airways resistance (Raw-272 patients), to measures of respiratory resistance measured with the APD including inspiratory (IR), expiratory (ER) and averaged (AR) resistance. Results: Measures of lung function were significantly correlated (p < 0.001). On regression analysis, between 7% - 17% of the variance (R2) for FEV1, PEF, and Raw was explained by APD measurements. Approximately 2/3 of the variance in FEV1 was explained by PEF measurements. Conclusions: APD measurements of lung function correlate with conventional measures. Future studies should be directed at exploring the use of the APD device in serial measures of lung function in patients with lung disease.
Mineral Chemistry and Thermobarometry of the Upper Eocene Volcanic Rocks in NE Tafresh, Iran  [PDF]
Neda Baranpurian, Mohamad Hashem Emami, Mansor Vossoughi Abedini, Rahim Dabiri
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.412045
Abstract: Petrography and chemistry of minerals show that rocks of Upper Eocene in northeast of Tafresh are composed mostly of andesitic basalt, basaltic andesite and andesite volcanic rocks. Mineralogically these rocks are composed of phenocrystals of olivine, clinopyroxene and plagioclase and main texture of them is porphyry with cryptocrystalline or microcrystalline matrix. In addition, aphyric and pitted textures (amygdala) are also observed. According to the results of EPMA, phenocrystals of plagioclase in mentioned rocks include a range of anorthite to albite minerals. Alkali feldspars also contain a range of sodic to potassic minerals. Pyroxene crystals include hedenbergite, augite and hypersthene. Olivine minerals are often of the ferrohornblendite type. Based on thermobarometry it is estimated that to form clinopyroxene crystals of basaltic andesite rocks, temperature between 750°C to 1000°C is needed. Andesitic basalt rocks at higher temperature (1100°C) and andesite rocks at lower temperature (below 750°C) are formed. According to the distribution of aluminum in clinopyroxenes, these minerals at pressures less than 5 kbar and water content between 5% to 10% are crystallized. The mineral composition indicates that these rocks are formed in a tensional environment.
Geochemistry and Petrogenesis of Tertiary Volcanic Rocks of the Eastern Roodbar, Alborz Mountain, North of Iran  [PDF]
Zahra Shafeie, Mohammad Ali Arian, Shahrouz Haghnazar, Mansour Vossoughi Abedini
Open Journal of Geology (OJG) , 2016, DOI: 10.4236/ojg.2016.610095
Abstract: In the Alborz Mountains of the eastern Roodbar (north of Iran), Tertiary volcanic rocks have a variety of composition between olivine basalt, basaltic andesite, pyroxene andesite and andesite. The presence of different xenoliths and xenocrysts is among the evidence of crustal contamination of these rocks. The positive correlations of CaO/Al2O3 vs to MgO and Al2O3 vs. SiO2 are of signs of the olivine and clinopyroxene fractionation in the variation trend of the area rocks. Positive correlations K2O/P2O5 vs with SiO2 and La/Sm vs. K2O/P2O5 demonstrate contamination of magma with the continental crust. The incompatible trace element patterns and their comparison with crustal contents indicate contamination of the rocks of the area with the lower and upper continental crust. Linear trends in the variation diagram of Nb/Y vs. Zr/Y, introduce two different source regions: a MORB source and the other continental crust for the rocks which are the genesis. The variations of Y/Nb vs. Zr/Nb and Rb/Y vs. Nb/Y reveal a crustal contamination of the magma originated from the MORB source. Geochemical studies
Sliding Mode Impedance Control of Flexible Base Moving Manipulators Using Singular Perturbation Method
M. Salehi,G. R. Vossoughi
Lecture Notes in Engineering and Computer Science , 2007,
Vibration Control of Flexible Base Mobile Manipulators under Impedance Controller Using New Control Element On the End Effector
M. Salehi,G. R. Vossoughi
Lecture Notes in Engineering and Computer Science , 2007,
A three-dimensional analysis of the sigmoid notch
Evan D. Collins,Faranak Vossoughi
Orthopedic Reviews , 2011, DOI: 10.4081/or.2011.e17
Abstract: Fractures of the distal radius are among the most common injuries of the upper extremity, though treatment has traditionally focused on restoration of the radiocarpal joint and late sequelae may persist. X-ray imaging underestimates sigmoid notch involvement following distal radius fractures. No classification system exists for disruption patterns of the sigmoid notch of the radius associated with distal radius fractures. This study quantifies the anatomy of the sigmoid notch and identifies the landmarks of the articular surface and proximal boundaries of the distal radioulnar joint (DRUJ) capsule. Computed tomography scans of freshly frozen cadaveric hands were used - followed by dissection, and three-dimensional reconstruction of the distal radius and sigmoid notch. The sigmoid notch surface was divided into two surfaces and measured. The Anterior Posterior (AP) and Proximal Distal (PD) widths of the articulating surface were reviewed, along with the radius of curvature, version angle and depth. The study showed that the sigmoid notch is flatter than previously believed - and only the distal 69% of its surface is covered by cartilage. On average, it has about nine degrees of retroversion, and its average inclination is almost parallel to the anatomical axis of the radius. Clinical implications exist for evaluation of the DRUJ involvement in distal radius fractures or degenerative diseases and for future development and evaluation of hemiarthroplasty replacement of the distal radius.
Dynamic Modeling of Stick-Slip Motion in a Legged, Piezoelectric Driven Microrobot
Ali Kamali Eigoli,GholamReza Vossoughi
International Journal of Advanced Robotic Systems , 2010,
Abstract: The motion of a stick-slip microrobot propelled by its piezoelectric unimorph legs is mathematically modeled. Using a continuously distributed mass model for the robot's body, the working equation of the mechanism is derived based on the assumption of linear Euler-Bernoulli beam theory and linear piezoelectric behavior. Moreover, the required condition for generating net motion is calculated in terms of physical characteristics of the microrobot. It is demonstrated that the higher the friction constant, then a lower average speed is obtained. Also, it is shown that a microrobot with heavier legs can move in a rougher environment. Regardless of the mass proportion between robot's main body and its legs, a certain level of speed can, always, be achieved. The proposed results will be well suited to design, construct, and control the microrobots moving with piezoelectric benders, as their feet.
Immobilization of α-Chymotrypsin on the Surface of Magnetic/Gold Core/Shell Nanoparticles
Mahmoud Kamal Ahmadi,Manouchehr Vossoughi
Journal of Nanotechnology , 2013, DOI: 10.1155/2013/830151
Abstract: Over the last decade, nanoparticles used as protein carriers have opened new avenues for a variety of biomedical applications. The main concern for these applications is changes in biological activity of immobilized proteins due to conformational changes on the surface of the carrier. To evaluate this concern, the preparation and biocatalyst activity of α-chymotrypsin-Fe3O4 @ Au core/shell nanoparticles were investigated. First, Fe3O4 @ Au core/shell nanoparticles were synthesized by coprecipitation method and citrate reduction of HAuCl4. TEM imaging revealed a core size of 13 ± 3?nm and a shell thickness of 4 ± 1?nm for synthesized nanoparticles. X-ray diffraction (XRD) was used to study the crystalline structure of the nanoparticles. Next, the enzyme was immobilized on the surface of synthesized nanoparticles by covalent bonding of Au shell with thiol and amine groups present in the protein structure (e.g., cysteine and histidine residues). FTIR and fluorescence spectroscopy were utilized to study secondary and tertiary structures of the immobilized enzyme. Results show that the secondary and tertiary structures of the enzyme remain virtually unchanged after immobilization on the nanoparticles surface. However, the biocatalyst activity of the enzyme was reduced by thirty percent, indicating possible conformational changes or active site occlusion. 1. Introduction In the past decade, magnetic nanoparticles have been studied for their biomedical applications [1] such as cellular therapy [2, 3], drug delivery [4, 5], hyperthermia, and magnetic resonance imaging (MRI) [6, 7]. While one can find a comprehensive discussion on critical factors for interaction of nanoparticles with living cell and proteins in reviews by Rauch et al. [8] and Mahmoudi et al. [9], it could be summarized that nanoparticles must have biocompatibility and interactive functions at the surface to allow their use in biomedical applications [10, 11]. Both organic and inorganic coatings have been used for surface modification of magnetic nanoparticles [10, 12]. Polyethylene glycol (PEG) and polyvinyl alcohol (PVA) are mainly used for polymeric surface modification [13, 14]. Silica and gold are the most common inorganic molecules used to modify the surfaces of magnetic nanoparticles [10, 13]. A silica layer provides a rich surface of silanol groups that react easily with alcohols and silane coupling agents [15, 16]. However, of the available surface modifiers, gold shows great potentials for biomedical applications [10]. Gold not only confers stability to nanoparticles in oxidative
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