Atomic Layer Deposition of Sc2O3Sc_2O_3 for Passivating AlGaN/GaN High Electron Mobility Transistor Devices

Polycrystalline, partially epitaxial $Sc_2O_3$ films were grown on AlGaN/GaN substrates by atomic layer deposition (ALD). With this ALD $Sc_2O_3$ film as the insulator layer, the $Sc_2O_3$/AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors showed excellent electrical performance with a high I$_{on}$/I$_{off}$ ratio of over 10$^8$ and a low subthreshold slope of 75 mV/dec. The UV/NH$_4$OH surface treatment on AlGaN/GaN prior to ALD was found to be critical for achieving these excellent figures. In addition, the $Sc_2O_3$dielectric is found to be negatively charged, which facilitates the enhancement-mode operation. While bare $Sc_2O_3$ suffers from moisture degradation, depositing a moisture blocking layer of ALD $Al_2O_3$ can effectively eliminate this effect.Chemistry and Chemical Biolog

Self-aligned AlGaN/GaN transistors for sub-mm wave applications

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 69-73).This thesis describes work done towards realizing self-aligned AlGaN/GaN high electron mobility transistors (HEMTs). Self-aligned transistors are important for improving the frequency of AlGaN/GaN HEMTs by reducing source and drain access resistance. The eventual fabrication of self-aligned transistors required the development of two different technologies that are described in this thesis. First, gate stacks that can survive the high temperature anneal necessary for forming ohmic contacts were demonstrated. Devices with three different gate stacks, composed of tungsten and a high-k dielectrics like HfO₂, A1₂O₃ and HfO₂/Ga₂O₃, were studied and compared with respect to DC transistor measurements, capacitor measurements and pulsed-IV measurements. Not only did these transistors survive the ohmic anneal but they showed superior performance with respect to transconductance, current density and dispersion than transistors with standard gates. Following the development of the gate stack, silicide-like technology where thin Ti-based films are deposited and annealed on the access regions to reduce access resistance was developed. Depositing and annealing thin Ti films were shown to reduce the sheet resistance by up to 30%. Finally, preliminary results regarding the fabrication of self-aligned transistors by using these gate stacks and the Ti-based access region metallization are reported in this thesis.by Omair I. Saadat.S.M

Do hands-free cell phone conversation while driving increase the risk of cognitive distraction among drivers? A cross-over quasi-experimental study

Background: Background: Conversation over the cell phone while driving is a known risk factor for road traffic crash. Using handsfree to talk on the cell phone may remove visual and manual distraction yet not the cognitive distraction. Objectives: The purpose of this study was to better understand the mechanisms of cognitive distraction due to hands-free cell phone conversation (HFPC) while driving. Methods: Twelve male and 12 female University students in Tehran, Iran, were selected via the consecutive convenient sampling method, and randomly assigned to one of the following administrations of cross-over quasi-experimental study design, during year 2016: Administration 1, participants performed the tests while involved in HFPC, took rest for 60 minute, and then performed the tests another time without HFPC; Administration 2, participants performed the tests without HFPC, took rest, and then performed the tests another time with HFPC. Each participant moved to the other administration after 7 to 10 days. The Vienna test system (VTS) was used to measure simple and choice reaction time, selective attention, visual orientation, and visual memory. Linear regression analysis was used to study the change in test scores due to HFPC. Results: The mean age of participants was 27.1±5.3 years. A history of road traffic crash (regardless of severity) was reported among 9 (37.5) participants in the previous year. Hands-free cell phone conversation while driving was directly associated with mean time correct rejection score (P < 0.01) (selective attention), omitted response (P < 0.01) and median reaction time (P < 0.01) (choice reaction time), and mean reaction time (P < 0.01) (Simple reaction time). Moreover, HPFC was inversely associated with sum hits (P = 0.05) (selective attention), incorrect (P < 0.02) and correct response (P < 0.01) (choice reaction time), score based on viewing and working time (P < 0. 01) (visual orientation), and visual memory performance (P < 0.01). Conclusions: Using hands-free devices to converse during driving, impaired reaction time, selective attention, visual orientation and visual memory, which are essential for safe driving. Thus, the use of these devices does not preclude cognitive distraction and should be restricted. © 2018, Iranian Red Crescent Medical Journal

Mems based bridge monitoring supported by image-assisted total station

In this study, the feasibility of Micro-Electro-Mechanical System (MEMS) accelerometers and an image-assisted total station (IATS) for short-and long-term deformation monitoring of bridge structures is investigated. The MEMS sensors of type BNO055 from Bosch as part of a geo-sensor network are mounted at different positions of the bridge structure. In order to degrade the impact of systematic errors on the acceleration measurements, the deterministic calibration parameters are determined for fixed positions using a KUKA youBot in a climate chamber over certain temperature ranges. The measured acceleration data, with a sampling frequency of 100 Hz, yields accurate estimates of the modal parameters over short time intervals but suffer from accuracy degradation for absolute position estimates with time. To overcome this problem, video frames of a passive target, attached in the vicinity of one of the MEMS sensors, are captured from an embedded on-axis telescope camera of the IATS of type Leica Nova MS50 MultiStation with a practical sampling frequency of 10 Hz. To identify the modal parameters such as eigenfrequencies and modal damping for both acceleration and displacement time series, a damped harmonic oscillation model is employed together with an autoregressive (AR) model of coloured measurement noise. The AR model is solved by means of a generalized expectation maximization (GEM) algorithm. Subsequently, the estimated model parameters from the IATS are used for coordinate updates of the MEMS sensor within a Kalman filter approach. The experiment was performed for a synthetic bridge and the analysis shows an accuracy level of sub-millimetre for amplitudes and much better than 0.1 Hz for the frequencies. © 2019 M. Omidalizarandi et al

Navigating Digital Transformation in the UAE: Benefits, Challenges, and Future Directions in the Public Sector

Digital transformation is a process in which the latest technologies are used in various business fields to keep pace with continuous changes. It involves the strategic and profound integration of digital technologies into an organization’s core business operations, processes, and models. In this study, a quantitative approach was used to study the impact of DT adoption on public sector transformational change projects in the United Arab Emirates (UAE). The diffusion of innovation theory (DIT) and the unified theory of acceptance and use of technology model (UTAUT) were used in the factor analysis. This study highlights that digital transformation initiatives in the UAE have benefited from a strategic alignment with government initiatives, such as AI and blockchain strategies. However, public sector organizations face challenges, such as the high costs of technology adoption and cybersecurity risks during integration with legacy systems. The significance of social influence, including elements like use behavior and behavioral intention, was identified as essential for digital transformation, suggesting the importance of technology in job performance. Similarly, digital transformation projects improve IT competence and reduce resistance to change among leaders and individuals. The findings underscore the importance of investing in infrastructure and continuous IT training to sustain digital transformation. More studies are required across specific sectors to further explore the impact and scalability of DT initiatives in the UAE public sector

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Do hands-free cell phone conversation while driving increase the risk of cognitive distraction among drivers? A cross-over quasi-experimental study

Background: Background: Conversation over the cell phone while driving is a known risk factor for road traffic crash. Using handsfree to talk on the cell phone may remove visual and manual distraction yet not the cognitive distraction. Objectives: The purpose of this study was to better understand the mechanisms of cognitive distraction due to hands-free cell phone conversation (HFPC) while driving. Methods: Twelve male and 12 female University students in Tehran, Iran, were selected via the consecutive convenient sampling method, and randomly assigned to one of the following administrations of cross-over quasi-experimental study design, during year 2016: Administration 1, participants performed the tests while involved in HFPC, took rest for 60 minute, and then performed the tests another time without HFPC; Administration 2, participants performed the tests without HFPC, took rest, and then performed the tests another time with HFPC. Each participant moved to the other administration after 7 to 10 days. The Vienna test system (VTS) was used to measure simple and choice reaction time, selective attention, visual orientation, and visual memory. Linear regression analysis was used to study the change in test scores due to HFPC. Results: The mean age of participants was 27.1±5.3 years. A history of road traffic crash (regardless of severity) was reported among 9 (37.5) participants in the previous year. Hands-free cell phone conversation while driving was directly associated with mean time correct rejection score (P < 0.01) (selective attention), omitted response (P < 0.01) and median reaction time (P < 0.01) (choice reaction time), and mean reaction time (P < 0.01) (Simple reaction time). Moreover, HPFC was inversely associated with sum hits (P = 0.05) (selective attention), incorrect (P < 0.02) and correct response (P < 0.01) (choice reaction time), score based on viewing and working time (P < 0. 01) (visual orientation), and visual memory performance (P < 0.01). Conclusions: Using hands-free devices to converse during driving, impaired reaction time, selective attention, visual orientation and visual memory, which are essential for safe driving. Thus, the use of these devices does not preclude cognitive distraction and should be restricted. © 2018, Iranian Red Crescent Medical Journal

A MicroRNA Linking Human Positive Selection and Metabolic Disorders

Postponed access: the file will be accessible after 2021-10-14Positive selection in Europeans at the 2q21.3 locus harboring the lactase gene has been attributed to selection for the ability of adults to digest milk to survive famine in ancient times. However, the 2q21.3 locus is also associated with obesity and type 2 diabetes in humans, raising the possibility that additional genetic elements in the locus may have contributed to evolutionary adaptation to famine by promoting energy storage, but which now confer susceptibility to metabolic diseases. We show here that the miR-128-1 microRNA, located at the center of the positively selected locus, represents a crucial metabolic regulator in mammals. Antisense targeting and genetic ablation of miR-128-1 in mouse metabolic disease models result in increased energy expenditure and amelioration of high-fat-diet-induced obesity and markedly improved glucose tolerance. A thrifty phenotype connected to miR-128-1-dependent energy storage may link ancient adaptation to famine and modern metabolic maladaptation associated with nutritional overabundance.acceptedVersio

Can environmental or occupational hazards alter the sex ratio at birth? A systematic review

More than 100 studies have examined whether environmental or occupational exposures of parents affect the sex ratio of their offspring at birth. For this review, we searched Medline and Web of Science using the terms ‘sex ratio at birth’ and ‘sex ratio and exposure’ for all dates, and reviewed bibliographies of relevant studies to find additional articles. This review focuses on exposures that have been the subject of at least four studies including polychlorinated biphenyls (PCBs), dioxins, pesticides, lead and other metals, radiation, boron, and g-forces. For paternal exposures, only dioxins and PCBs were consistently associated with sex ratios higher or lower than the expected 1.06. Dioxins were associated with a decreased proportion of male births, whereas PCBs were associated with an increased proportion of male births. There was limited evidence for a decrease in the proportion of male births after paternal exposure to DBCP, lead, methylmercury, non-ionizing radiation, ionizing radiation treatment for childhood cancer, boron, or g-forces. Few studies have found higher or lower sex ratios associated with maternal exposures. Studies in humans and animals have found a reduction in the number of male births associated with lower male fertility, but the mechanism by which environmental hazards might change the sex ratio has not yet been established