First principles insights on CO adsorption on metal surfaces

Density functional theory (DFT) has been regularly exploited for meticulous studying of complex surface interactions at a molecular orbital scale. However, DFT calculations usually yield inaccurate thermodynamics results that contradict experimental findings. A clear example is the CO adsorption puzzle caused by the wrong estimation of adsorption sites, especially for the (111) transition metal surfaces. The puzzle is still not fully resolved and a complete adsorption picture is yet to be reported. Herein, we demonstrate the reliability of DFT calculations for the study of local bond properties, despite the wrong energetics predictions. We also highlight the importance of considering a comprehensive analysis of all the possible adsorption sites over distinctive surface facets. Each surface facet, with its unique arrangement of atoms, results in a varying adsorbate behavior, although the same adsorption site is studied. Investigating these variations gives insights about the influence of surface atomic arrangement on the orbitals\u27 interactions. Within the investigation, it is found that the varying density of orbitals, with the matching symmetry for interaction at different adsorption sites, affects the magnitude of orbital interaction, and thus, acts as an additional factor for determining the site preference. Based on the frontier (5σ and 2π*) orbital energy description, calculated using RPBE functional, new perceptions to the understanding of the adsorption puzzle have been exposed. In addition, we emphasize the significance of considering a holistic analysis of adsorbate orbitals, not only limited to the main CO frontier orbitals. This approach leads to a better understanding of the surface bonding and CO final structure. This investigation can help in providing guidelines for innovating design principles for materials, based on the required adsorbate behavior and charge transport phenomena, to be used for catalysis and sensors applications

ICTs readiness among MOOC learners : a cross-national analysis

Massive open online courses (MOOCs) attract the attention of educators who desire to extend higher education to learners around the globe. MOOCs also interest learners with Internet access who can benefit from them and enroll at no cost. However, research indicates the importance of learners’ readiness for online learning in order to take advantage of these courses and the importance of investigating factors that influence learners’ satisfaction with MOOCs. In order to examine these aspects, two different types of surveys were conducted. Framed by the second-level digital divide approach and resources and appropriation theory, this study surveyed MOOC learners to investigate their readiness for online learning. It measured learners’ levels of engagement with information and communications technologies (ICTs) and learners’ characteristics (self-efficacy and locus of control). The study analyzed one source of data collected from surveying 2,882 learners who were enrolled in any of five MOOCs that were offered in either English or Arabic and through two MOOC providers based in the U.S. and Saudi Arabia. The findings identified significant differences among learners who live in various regions or countries with different economic classifications. For example, MOOC learners who live in either North America or developed economies have significantly higher levels of engagement with ICTs, self-efficacy, and locus of control than learners who live in Arab States or developing economies respectively. In several regions, such as North America and Asia and the Pacific, male MOOC learners have significantly higher levels of engagement with ICTs than females. Additionally, based on the theory of independent learning and teaching, the three types of interaction model, and the technology acceptance model, this study investigated factors that influence learners’ satisfaction with MOOCs. It also examined effects of age and level of education of MOOC learners on their perceptions concerning the importance of five course aspects. Another survey asked 1,762 learners who were enrolled in any of four MOOCs. The results showed that the learner perceived usefulness, teaching and learning aspects of the MOOC, and learner-content interaction as important satisfaction factors. The results revealed that both age and level of education have significant effects only on the importance of three course aspects. Future directions in MOOCs research are discussed.Radio-Television-Fil

The image of Turkey in Egyptian media: Content and discourse analysis of the coverage in three Egyptian newspapers

This study investigates the image of Turkey in Egyptian newspapers by conducting a content and discourse analysis of three Egyptian newspapers, Al-Ahram, El-Shorouk, and Almasry Alyoum, from January 2012 to December 2014. Based on previous literature, this study applied two theoretical frameworks: 1) Benedict Anderson\u27s hypnosis of imagined communities and 2) media framing theory. To apply media framing, the Semetko and Valkenburg (2000) framing scale was employed. Following that, a rhetorical discourse was used to investigate Anderson\u27s thesis. The study\u27s finding matched Semetko and Valkenburg\u27s framing scale. Both indicated that the attribution of responsibility is the most frequent frame in news. Finally, the discourse analysis resulted that newspapers could be deployed as an instrument to disseminate shared thoughts and ideologies among diverse citizens

Dual tuned 1H/31P quadrature microstripline-based transmit/receive switch for 7 Tesla magnetic resonance imaging

A dual tuned transmit/receive (T/R) Switch for 7 tesla magnetic resonance imaging (MRI) that is based on concentric microstripline (MSL) coupler is introduced. The proposed switch is designed using two concentric MSL quadrature couplers on the top and bottom faces of the switch. The switch can be used to handle two frequency signals to/from two radio frequency (RF) coils. In this article, a 1H/31P atomic nuclei are excited. The two MSLs on the upper face of the switch are designed to transmit 298 and 120.6 MHz signals into RF coils, whereas each of the identical upper and lower MSLs are used to receive these signals from the RF coils. This switch can be used to transmit/receive signals from two RF coils at the same time, one work with 1H and the second with 31P atomic nuclei, and without any tuning. The proposed switch has been designed and simulated using the electromagnetic microwave studio computer simulation technology (CST). It demonstrates good matching (≈17 dB), low insertion loss (≈0.3) and high isolation (>70) for the 1H and 31P magnetic resonance signals at transmit mode. During receive mode, It demonstrates good matching (>20 dB), low insertion loss (≈0.2) and high isolation (>70) for the 1H and 31P magnetic resonance signals

Two-section branch-line hybrid couplers based broadband transmit/receive switch

This article introduces a broadband microstripline-based transmit/receive switch for 7-Tesla magnetic resonance imaging. The designed switch aims to handle a signal of multiple frequencies to/from a multi-tuned radio-frequency coil that resonates at frequencies corresponding to the speed of precession of a wide range of atomic X-nuclei, at the same time and without tuning. These include 1H, 23Na, 13C, 31P, 19F, and 7Li used in magnetic resonance spectroscopy as a measure to the existence of many diseases. The fundamental and third harmonic center frequencies of the switch are adjusted to resonate at two broadbands covering a wide range of atomic X-nuclei. Two section branch-line hybrid couplers with phase inverters are designed to build the broadband switch. The designed switch used the minimum trace widths of transmission lines that reveal a compact size without increasing the heat and then the loss beyond specific values. The couplers and the switch S-parameters exhibited good return loss (<-10 dB), high isolation (<-40 dB), less insertion loss (<1 dB) and two clear wide bands covering many atomic X-nuclei used in diagnosis, at the same time and without the need for any tuning circuit during operation

High Impedance Surface – Electromagnetic Band Gap (HIS-EBG) Structures for Magnetic Resonance Imaging (MRI) Applications

High Impedance Surface – Electromagnetic Band Gap (HIS-EBG) structures are one class of Metamaterials with unique and useful electromagnetic properties. This thesis proposes the first application of EBG structures for Magnetic Resonance Imaging (MRI) applications, with the aim of improving effectiveness of coils in creating RF magnetic flux density inside the patient or a phantom. The anti-phase currents in the metallic ground planes placed underneath transmit RF coils for ultrahigh field MRI represent the main reason for the reduction in RF magnetic flux density above these coils (inside the load). In addition, they support the propagation of surface waves which radiate from edges and corners wasting power in the back hemisphere. The objective of this thesis is to investigate the potential of improving the efficiency of a well-established RF coil for 7 Tesla MRI by replacing the standard ground planes with specially designed EBG structures which exhibit novel electromagnetic properties: The reflection of such structures exhibits a frequency range over which an incident electromagnetic wave does not experience a phase reversal, and the image currents appear in-phase rather than out of phase as they do on the standard ground planes. Due to this, the EBG structure is termed an artificial magnetic conductor. Furthermore, it suppresses the propagation of surface waves. In this thesis, novel EBG structures are proposed and fabricated, and their electromagnetic properties are characterized analytically, numerically, and are validated by measurements. The RF coil backed by our proposed EBG ground planes exhibits improvement in the magnetic flux density inside phantoms compared to the case when it is backed by conventional ground planes of the same dimensions. A novel multilayer offset stacked polarization dependent EBG structure is designed to work as a soft surface with anisotropic surface impedance. The designed structure solves the problem of the limited space available in MRI magnet bores. The RF coil backed by the proposed soft surface exhibits stronger magnetic field inside the phantom, while the electric field and the specific energy absorption rate values are reduced.High Impedance Surface – Electronic Band Gap (HIS-EBG) Strukturen für den Einsatz in der Magnetoresonanz-Tomographie (MRT) High Impedance Surface – Electronic Band Gap (HIS-EBG) Strukturen bilden eine Klasse von Metamaterialien mit einzigartigen elektromagnetischen Eigenschaften, welche nicht ohne weiteres in der Natur vorkommen. In dieser Arbeit werden zum ersten Mal EBG Strukturen für den Einsatz in Ultra-Hochfeld Magnetresonanz-Tomographie Anwendungen vorgeschlagen, mit dem Ziel die Effektivität von Spulen, welche für die Erzeugung von hochfrequenten magnetischen Flussdichten in Patienten oder Phantomen verwendet werden, zu erhöhen. Gegenphasige Ströme in den metallischen Masseflächen unterhalb der HF Sende-Spulen sind der Hauptgrund für die Reduzierung der hochfrequenten magnetischen Flussdichten oberhalb dieser Spulen. Ferner kommt es zur Anregung von Oberflächenwellen auf den metallischen Masseflächen und zur Abstrahlung an den Kanten und Ecken, wodurch Leistung in eine unerwünschte Richtung abgestrahlt wird. Das Ziel dieser Arbeit ist die Untersuchung der Möglichkeiten zur Verbesserung des Wirkungsgrads von gängigen HF Spulen für 7 Tesla MRT, bei welchen die Standard- Massefläche durch speziell entworfene EBG Strukturen ersetzt wurde. Bei der Reflektion an solchen Strukturen erfährt die einfallende elektromagnetische Welle in einem bestimmten Frequenzbereich keine Umkehrung der Phase. Im Gegensatz zur Standard-Massefläche, in welcher gegenphasige Ströme entstehen, sind die Ströme in der EBG Struktur gleichphasig. Auf Grund dessen werden die EBG Strukturen als künstliche magnetische Leiter bezeichnet. Des Weiteren wird die Ausbreitung von Oberflächenwellen in EBG Strukturen unterdrückt. In dieser Arbeit, werden einige neuartige EBG Strukturen vorgestellt. Die elektromagnetischen Eigenschaften dieser Strukturen werden sowohl analytisch als auch nummerisch beschrieben und messtechnisch validiert. Die HF Spulen über der EBG Struktur weisen, im Vergleich zum Aufbau über einer herkömmlichen Massefläche, eine deutlich erhöhte magnetische Flussdichte im inneren des Phantoms auf. Des Weiteren wurde eine neuartige, versetzt aufgebaute und polarisationsabhängige Multilagen-EBG Struktur entworfen mit reduzierten Abmessungen um als anisotrope „Soft“-Oberflächenimpedanz fungieren zu können. Die HF Spule über dieser vorgeschlagenen „Soft“ Oberflächenimpedanz führt im inneren des Phantoms zu einer Erhöhung der magnetischen Feldstärke, wobei die Elektrische Feldstärke und die Spezifische Absorptionsrate reduziert werden

Health Belief Model Based Intervention for Improving Nursing Students’ Knowledge and Behavior Regarding Osteoporosis Prevention

Osteoporosis is a preventable chronic disease that begins during childhood. It is a silent killer not diagnosed until an individual presents with a low impact fracture. Health belief model (HBM) based intervention increase awareness of risk factors and preventive behaviors. Aim: This study aimed to investigate the effect of health belief model based intervention on nursing students’ knowledge and behavior regarding osteoporosis prevention. Sample: A convenient sample of 100 female nursing students was included. Setting: The study was conducted at Applied Medical Sciences Collage, nursing department in Al Dawadmi, from September -November 2013. Data were collected before and after one month from the intervention. Results: Students knowledge about osteoporosis was improved significantly post implementation of the HBM based intervention, also there was a significant difference between students perception regarding health believe subscale before and after the HBM based intervention. Also osteoporosis protective behaviors among students were significantly changed post the intervention and there was a significant correlation between their knowledge, perception and level of calcium intake & daily activity post the intervention. Conclusion: Osteoporosis is a pediatric disease with geriatric consequences which need HBM based educational intervention during the adulthood stage to improve adult female knowledge, maintain osteoporosis preventive behaviors, and improve their health believes. Key words: Health belief model (HBM) based intervention, osteoporosis prevention, nursing students

Kinetic, Equilibrium and Application Studies for Removal of Methylene Blue from Aqueous Solution Using Sesbenia Dates Activated Carbon

In the present work, sesbenia dates as local agricultural waste has been successfully used for the preparation of activated carbon (AC) by sulphuric acid. This sulphuric acid based activated carbon (SD) and (MSACS) were used for the removal of one cationic dye viz., methylene blue (MB) from aqueous solutions. The structure and physical and chemical properties of (SD) and (MSACS) are investigated using (FTIR) and (SEM) analysis and pH surface and Boehm titration. The effect of the differential experimental parameters controlling the adsorption of dye onto (SD) and (MSACS), were thoroughly investigated, such as the effect of pH, initial dye concentration, contact time and adsorbent dosage in batch mode. Employment of equilibrium isotherm models for the description of adsorption capacities of (SD) and (MSACS) explores the good efficiency of the Langmuir model for the best presentation of experimental data with maximum adsorption capacity of 38.02 mg/g (SD) and 277.77 mg/g (MSACS) for (MB) dye. The kinetic data were fitted to the pseudo-second-order kinetic model. Thermodynamic parameters were evaluated to predict the nature of adsorption. These results point out the exothermic and spontaneous nature of the sorption process. The results demonstrate that (SD) and (MSACS) are effective in the removal of MB dye from aqueous solutions and can be used as an alternative to the high-cost commercial adsorbents

Developing Proactive Protocol for Blood-borne and Body Fluids Infections Prevention among Students of Health Professional Colleges in King Khalid University

Background: Exposure to blood and body fluids is an important hazard for health professional students, which places them at a high risk for blood-borne infections. They are exposed to blood-borne diseases most commonly through accidental needle sticks and sharp injuries. Blood-borne infections are associated with significant morbidity and mortality. The introduction of safety measures guide to prevent accidental blood-borne infections in health professional college curricula are essential. Hence, the present study aims develop proactive protocol for prevention of blood borne and body fluids infections among nursing, medical, and dental students in King Khalid University. Setting; the study was conducted at Faculty of Medicine, Dental, and Nursing in University Center for the Study of Female Students at King Khalid University, Saudi Arabia. Subjects; a purposive sample of 300 female students, 130 from nursing, 126 from medical, and 44 from dental program were included in the present study. Tool; a questionnaire sheet developed by researchers based on reviewing related literature and consists of five parts was used for data collection. Results and Conclusion; the majority of studied participants reported the needle-stick injuries occur when drawing intravenous blood and giving patient intravenous injection, the primary factor lead to sharp injures is broken some ampoule and using sharp instruments, they need to know preventive and precautions to prevent blood-born infection and equipment uses to avoid it. Also it was found no significant difference between participant students regarding their attitude toward standard percussion and preventive measures for blood borne infection. Recommendations; Findings of the present study have important implication for developing a Proactive Protocol of Blood-borne and Body Fluids Infections prevention among students of nursing, medical, dental colleges. This focused on proactive and controlling blood-borne infection diseases, needle-stick, and sharp injuries and lead to a healthy life of students. Key words: proactive protocol, blood-borne infection, Needle stick injuries, Sharps injuries, health professional collages Abbreviations: HCWs healthcare workers, HIV immunodeficiency virus, HBV hepatitis B virus, HCV hepatitis C virus, NSISIs needle stick & sharp injuries, OSHA Occupational Safety and Health Administration, PEP post-exposure prophylaxis, CDC Disease Control and Prevention, SPs standard precautions, UP universal precautions, BBFEs blood and body fluid exposures, PPE personnel protective equipment.

Comparison between Preterm versus Full Term Septic Neonates Whose Feeding Is Powdered Milk Formula Regarding Cronabacter Sakazakii

Background: Foodborne pathogen Cronobacter sakazakii (CS) has been detected around the world. When it comes to foodborne bacteria, C. difficile (CS) is one of the most prevalent diseases, particularly among infants with low birth weight and preterm neonates. Objective: To compare between the incidence of Cronobacter Sakazakii infection among preterm versus full term septic neonates whose feeding is powdered milk formula. Patients and Methods: Our study was a comparative cross-sectional study and included 50 neonates: 25 full term and 25 premature. It was conducted at Pediatrics Department, Zagazig University Hospital and the patients’ status fulfilled the inclusion and exclusion criteria. Medical history, clinical examination, and laboratory tests were performed on all patients. Collection of specimens and culture and sensitivity tests for the isolates were also done. Results: There was significant increase of prevalence of Cronobacter sakazakii in preterm more than full term. The sepsis score and its associated characteristics varied significantly between the two groups. With time, increasing temperature led to reduce number of C. sakazakii in reconstituted infant powdered milk Conclusion: Powdered infant formula (PIF) can be contaminated with C. sakazakii, which can cause sickness in infants who are fed PIF rather than breast milk, and in preterm infants rather than full-term ones