Axisymmetric polydimethysiloxane microchannels for in vitro hemodynamic studies

The current microdevices used for biomedical research are often manufactured using microelectromechanical systems (MEMS) technology. Although it is possible to fabricate precise and reproducible rectangular microchannels using soft lithography techniques, this kind of geometry may not reflect the actual physiology of the microcirculation. Here, we present a simple method to fabricate circular polydimethysiloxane (PDMS) microchannels aiming to mimic an in vivo microvascular environment and suitable for state-of-the-art microscale flow visualization techniques, such as confocal µPIV/PTV. By using a confocal µPTV system individual red blood cells (RBCs) were successfully tracked trough a 75 µm circular PDMS microchannel. The results show that RBC lateral dispersion increases with the volume fraction of RBCs in the solution, i.e. with the hematocrit

An experimental study of buzz instability in an axisymmetric supersonic inlet

AbstractAn experimental study was carried out on an axisymmetric supersonic inlet with external compression. The scope of this study was to investigate the general characteristics of the inlet buzz under various design and off-design conditions. The model was equipped with accurate and high frequency pressure sensors and the tests were conducted at Mach numbers varying from 1.8 to 2.5, at various angles of attack, and at different mass flow rates. Shadowgraph flow visualization, together with a high speed camera, was used to capture the external shock structure in front of the inlet. Frequencies of buzz were obtained from both the shadowgraph pictures and analysis of the pressure data. The amplitude of the shock wave motion was measured from the visualization pictures, too. The results show that for low mass flow rates, buzz frequency is almost independent of Mach number, while at a higher mass flow rate, the frequency of the shock oscillation increases with Mach number. Further, for each free stream Mach number, as the mass flow rate decreased, the amplitude of the shock movement grew, but its frequency decreased

Duality with expanding maps and shrinking maps, and its applications to Gauss maps

We study expanding maps and shrinking maps of subvarieties of Grassmann varieties in arbitrary characteristic. The shrinking map was studied independently by Landsberg and Piontkowski in order to characterize Gauss images. To develop their method, we introduce the expanding map, which is a dual notion of the shrinking map and is a generalization of the Gauss map. Then we give a characterization of separable Gauss maps and their images, which yields results for the following topics: (1) Linearity of general fibers of separable Gauss maps; (2) Generalization of the characterization of Gauss images; (3) Duality on one-dimensional parameter spaces of linear subvarieties lying in developable varieties.Comment: 28 pages, v3: added some examples, v2: the title has been changed from v1 "Linearity of general fibers of separable Gauss maps

Effect of Minimally Invasive Endotracheal Tube Suctioning on Suction-Related Pain, Airway Clearance and Airway Trauma in intubated Patients: A Randomized Controlled Trial

Background: Due to the frequency and risks associated with endotracheal suctioning, there is a need to examine clinical practice critically and identify clinical research to guide practice. Correct technique and preparation by the clinicians can assist to reduce the risks of adverse events and the level of discomfort for the patients. Objectives: The current study aimed to investigate the effects of routine versus the minimally invasive endotracheal tube suctioning procedure on suction-related pain, airway clearance and airway trauma in patients who were intubated. Methods: In this randomized clinical trial, 64 patients with intubation in the intensive care units (ICUs) of Alzahra Hospital, Isfahan, Iran, were randomly allocated to minimally invasive endotracheal tube suctioning (MIETS) and routine endotracheal tube suctioning (RETS) groups. Pain intensity was assessed immediately before, immediately after and 10 minutes after endotracheal tube suctioning (ETS). Airway clearance was defined by numbers of suctioning and airway trauma noted after suctioning. The Chisquare test, independent T-test, and repeated measures analysis of variance were performed to analyze the data. Results: There wasnosignificant difference in thenumberof suctions needed to effectively clear airway between the two groups. No significant differences were observed in the pain score changes during the three -time measurements in the MIETS group. However, in the RETS group the increase of pain scores were statistically significant during the three- time measurements. In addition, the numberof airway traumatizationwassignificantly higher in the RETS group. Thenumberof medications used as a pain relief during 10 minutes after the ETS was significantly higher in the RETS group. Conclusions: The results of the study suggest that using MIETS instead of RETS caused a lower incidence of airway traumatization and lower suction-related pain intensity. In addition, MIETS was sufficiently effective, the same as RETS, to remove airway secretions. Hence, MIETS may be useful to reduce the complications of ETS as long as being effective to remove airway secretions

Augmented Reality in Smart Cities: A Multimedia Approach

Intro: This paper presents an advance overview of utilizing Augmented Reality (AR) in smart cities. Although, Smart cities contain six major aspects (mobility, economy, government, environment, living, and people), this paper focuses on three of them that have more potentiality in using virtual assistant (mobility, environment, and living). Methodology: Presenting a state-of-the-art review studies undertake between 2013 and 2017, which is driven from highlighted libraries is the aim of this research. After exact examine, 15 emphasized studies are chosen to divide the main aspects while 120 selective articles are supporting them. These categorizes have been critically compared with an aim, method and chronological perspectives. Results: First of All, Environmental issues (Museums industry) attract the most attention of researchers while the living issues (maintenance) have lower significant compare t latter and mobility (indoor-outdoor navigation) attract the least. Moreover, a close connection between academic and industry fields is going to be created. Conclusions: it has been concluded that, because of economic advantages, utilizing AR technology has improved in the tourism and maintenance. Moreover, until now, most of studies try to prove their concept rather than illustrate well stablished analytic approach. Because of hardware and software improvement, it is essential for the future studies to evaluate their hypothesis in a real urban context

The Impact of Suspect Descriptions in University Crime Reports on Racial Bias

Crime reports often include suspect descriptions to alert community members and aid in police investigations. However, vague descriptions of suspects with racial identifiers can potentially do more harm than good. We first conducted an archival study to examine the frequency of reporting suspect race, as well as the relationship between the inclusion of race and the likelihood that the suspect was caught. Then we conducted an experimental study to examine how reporting race may affect overt and subtle racial attitudes. We found no significant relationship between the racial identification of a suspect and the likelihood that the suspect was caught in our archival study. However, our findings from the experimental study demonstrate increased overt and subtle racial bias towards Black people when comparing participants who read a crime report with a Black suspect to those who read one about a suspect with no racial identification. Implications and future directions are discussed

Structure of Polyelectrolytes in Poor Solvent

We present simulations on charged polymers in poor solvent. First we investigate in detail the dilute concentration range with and without imposed extension constraints. The resulting necklace polymer conformations are analyzed in detail. We find strong fluctuations in the number of pearls and their sizes leading only to small signatures in the form factor and the force-extension relation. The scaling of the peak in the structure factor with the monomer density shows a pertinent different behavior from good solvent chains.Comment: 7 pages, 5 figures. submitted to EP

Energy Depandence of Isomeric Yield Rations of Fission Products in 232Th + P System

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A Study of Sum Peak Method in Biological Substances by Using 111In

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