bluuebunny/crossref_metadata_2025 huggingface dataset:
Is there a Supercharged Gas Turbine in your Future?
Authors: Langston Lee S.
Published: March 2018

This article discusses various features of supercharged gas turbine and supercharged analysis. One 400 MW supercharged gas turbine power plant variant analysed by Wettstein yielded a predicted thermal efficiency of 60 percent, rivaling current combined cycle values. The supercharged gas turbine power plant proposed by Wettstein is a semi-closed (SC) cycle. The SC cycle is an amalgamation of closed and open cycles. It consists of a gas turbine having an internal combustor for energy input to the cycle. With a SC cycle, a designer now has some of the best features of both open and closed to move SC power plant operation in different directions. With internal combustion, the SC cycle is not constrained by the temperature limitations of the closed cycle. The supercharged gas turbine power plant looks very promising. In another ASME paper, Wettstein shows how gas turbine supercharging could benefit marine propulsion.
Rolling Back Home
Authors: Moedinger Linn W.
Published: March 2018

This article relates history and various aspects of steam locomotive boilers and their relevance in present and future. Prior to 1950, boilers for steam locomotives were built in the United States using primarily lower carbon steel products. The Subgroup on Locomotive Boilers was formed in 2010. Four and a half years later, its work was published as Part PL, Requirements for Locomotive Boilers. The ASME’s Subgroup for Steam Locomotives has taken the approach of codifying both best practices and Code material from steam days. The new locomotive code, Part PL in Section I can truly be looked at as a beginning. New materials and methods will now have a place to be vetted within the unique perspective of steam locomotive operation so as to ensure safe steam locomotive boilers for centuries to come.
Ghost Knifefish in the Machine
Authors: Ferber Dan
Published: March 2018

This article focuses on different research and development tasks intended towards creation of agile swimming robot. Armed with extraordinary agility and electrical sensors that show the location of insect larvae, the black ghost knifefish haunts at night. An underwater robot based on the ghost knifefish could work in the murkiest waters. Malcolm MacIver, a professor of mechanical engineering and neurobiology at North-western University, is building a prototype of such an agile ROV in his laboratory. Active electrosense could do more for ROVs and robots, MacIver said. It may soon be able to distinguish living organisms, including divers, from inanimate objects by sensing capacitance – the ability of a material to induce a phase lag between voltage and current – MacIver reported in 2012 at the International Conference on Intelligent Robots and Systems. Down the road, the bioroboticists hope to incorporate another ant navigational skill into a robot – a neat ability to detect polarized sunlight and use it to determine compass direction.
The Industrial Internet and the Future of Work
Authors: Annunziata Marco , Biller Stephan
Published: March 2018

This article focuses on the transformation and dimming lines between digital and physical worlds.

Industrial Internet tools and applications also help people collaborate in a faster and smarter way – making jobs not just more efficient but more rewarding. Technological progress and economic growth are contributing to a seismic shift in the role that human beings play in the production process. Technological progress, notably in high-performance computing, robotics, and artificial intelligence, is extending the range of tasks that machines can perform better than humans can. The Future of Work is being shaped by a profound transformation, driven by the meshing of the digital and the physical worlds, the emergence of new design and production techniques, and a seismic shift in the role that human beings play in the production process. Technological progress is expected to push a growing share of the workforce toward creativity and entrepreneurship, where humans have a clear comparative advantage over machines.
Modular Interoperability in Surgical Robotics Software
Authors: Kazanzides Peter , Deguet Anton , Vagvolgyi Balazs , Chen Zihan , Taylor Russell H.
Published: March 2018

This article reviews on modular interoperability of the software that is used for these types of systems. One key point is that while hierarchical multi-rate control may be suitable for the master and slave robots, there is also a requirement to handle the video and ultrasound images. This article presented an overview of surgical robot systems, with the recognition that these systems are not just robots, but integrated systems that include robots, databases, and real-time sensors such as video and other medical imaging devices. Common research platforms, such as the da Vinci Research Kit and Raven II, have recently become available. This has underscored the need for modular software interoperability, so that researchers can share software modules and more easily integrate other robots and devices. Standardization and interoperability are most applicable at the higher software layers, and can benefit from the availability of widely-adopted middleware such as ROS. Other interface protocols, such as OpenIGTLink, can be useful due to their wide support within the medical imaging and image-guided intervention domains.
Instruments in Your Pocket
Authors: Alexander Kathryn
Published: March 2018

This article discusses the revolution that smartphones, apps, and add-on devices have brought in every person’s life. Sensors and apps are turning smartphones into engineering measurement tools. Increasingly, engineers are reaching for their smartphones to test products and equipment. The latest generation of smartphones feature sensor suites and apps that have turned the smartphone into a pocket-size laboratory of engineering instruments. Smartphones and apps have matured far beyond the consumer market to become real engineering tools. In 2013 Samsung Electronics Co. Ltd., added temperature and humidity sensors and pulled ahead of the market with the largest sensor suite. Many apps are available free to the user. The developers monetize their offerings by putting ads in the apps or by offering purchases to upgrade to a ‘pro’ version of the app with more functionality. The apps have also been used in industry to diagnose problems associated with vibration in mechanical systems, and by an electrical company that uses vibration to determine tension in cables. Smartphones, apps, and add-on devices are evolving rapidly, and a smart choice could make your next engineering project go mobile.
To MOOC, or Not to MOOC, That is the Question
Authors: Gad-el-Hak Mohamed
Published: March 2018

This article presents view of two books on massive open online courses (MOOCs). The two books ride on a homologous theme: the revolutionary future of undergraduate education. A Whole New Engineer, by David E. Goldberg and Mark Somerville, describes the change in engineering education that is taking place at the newly minted Olin College of Engineering and the more established the University of Illinois at Urbana-Champaign. Another book, The End of College, Kevin Carey prognosticates the future of learning and the university of everywhere based upon emerging MOOCs. Rising tuition prices and a flagging global economy, combined with advances in information technology, are leading to a rapidly changing scene from traditional lecture-hall teaching to online education.
The Lines on the Road: Infrastructure in Perspective
Authors: Petroski Henry
Published: March 2018

This article discusses various road infrastructure history and perspectives that could help in improving future infrastructure. The visibility of pavement markings has continued to be problematic, especially where winter and snow are virtually synonymous. The American reinvention of the highway centreline has been described as ‘the most important single traffic safety device in the history of auto transportation.’ The solid white line that marks the right-hand edge is thus considered another significant innovation. The white line delineating the pavement’s right-hand edge was explicitly advocated in the 1961 manual, and the 1978 edition made it required for all multilane rural highways. Such standardization, while it may take time to be codified, certainly does make our highways safer and less stressful to navigate.
Off to the Races
Authors: Ferber Dan
Published: March 2018

This article is on the efforts that are being made to manufacture and launch automatic cars successfully. Chris Gerdes and his team have been doing research and putting lot of efforts in designing self-driving cars that can handle emergencies even better than the very best human drivers. The research team studies professional race car drivers to learn minutest details for their algorithms and measurements. In a way, the research team analysts teach a car to drive like a race car driver - to calculate when to brake before a turn, how much to let up on the brake entering a turn, and how much to throttle coming out of it. Impressive for a car with no driver, however, Gerdes and his team want to raise the stakes. However, the team’s autonomous cars have operated alone on the tracks or roads. Now, Gerdes is ready to test them in traffic and on icy roads that will force the automated cars to adapt driving tactics midstream.
Surplus Torque Elimination Control of Electro-Hydraulic Load Simulator Based on Actuator Velocity Input Feedforword Compensating Method
Authors: Li Zhihui , Shang Yaoxing , Jiao Zongxia , Wu Shuai , Yao Jianyong
Published: March 2018

Electro-hydraulic load simulator (EHLS) is a typical closed-loop torque control system. It is used to simulate the load of aircraft actuator on ground hardware-in-the-loop simulation and experiments. In general, EHLS is fixed with actuator shaft together. Thus, the movement of actuator has interference torque named the surplus torque on the EHLS. The surplus torque is not only related to the velocity of the actuator movement, but also related to the frequency of actuator movement. Especially when the model of the actuator and EHLS is dissimilar, the surplus torque is obviously different on different frequencies. In order to eliminate the surplus torque for accurate load simulation, the actuator velocity input feedforword compensating method (AVIFC) is proposed in this paper. In this strategy, the actuator velocity synchronous signals are used for compensation of different frequency actuator movement to eliminate surplus torque on different frequencies. First, the mathematical model of EHLS and the actuator system is established. Based on the models, the AVIFC method is proposed. It reveals the reason that generates surplus torque on different frequencies of actuator. For verification, simulations and experiments are conducted to prove that the new strategy performs well against low, medium, and high frequency movement interference. The results show that this method can effectively suppress the surplus torque with different frequencies and improve precision of EHLS with actuator movement.
Improved Results on Finite-Time Stability Analysis of Neural Networks With Time-Varying Delays
Authors: Saravanan S. , Syed Ali M.
Published: March 2018

This paper investigates the issue of finite time stability analysis of time-delayed neural networks by introducing a new Lyapunov functional which uses the information on the delay sufficiently and an augmented Lyapunov functional which contains some triple integral terms. Some improved delay-dependent stability criteria are derived using Jensen's inequality, reciprocally convex combination methods. Then, the finite-time stability conditions are solved by the linear matrix inequalities (LMIs). Numerical examples are finally presented to verify the effectiveness of the obtained results.
Adaptive Robust Control for Mirror-Stabilized Platform With Input Saturation
Authors: Song Jiangpeng , Zhou Di , Sun Guangli
Published: March 2018

The line-of-sight (LOS) kinematics and dynamics of a mirror-stabilized platform are derived using the virtual mass stabilization method. Accounting for the coupled and nonlinear kinematics and dynamics, the uncertainty of external disturbances, and the actuator input saturation in the mirror-stabilized platform, a modified adaptive robust control (ARC) scheme is proposed based on the command filtered method and the extended state observer (ESO). The command-filtered approach is used to ensure the stability and tracking performance of the adaptive control system under the input saturation. In the proposed scheme, the ESO is designed to observe the modeling error and unknown external disturbances. The stability of the control system is proved using the Lyapunov method. Simulation results and experimental results proved that the proposed control scheme can effectively reduce the occurrence of input saturation, attenuate the effect of unknown disturbances, and improve the position tracking accuracy.
Multiparameter Spectral Analysis for Aeroelastic Instability Problems
Authors: Pons Arion , Gutschmidt Stefanie
Published: March 2018

This paper presents a novel application of multiparameter spectral theory to the study of structural stability, with particular emphasis on aeroelastic flutter. Methods of multiparameter analysis allow the development of significant new solution and analysis algorithms for aeroelastic flutter problems; including direct solvers for polynomial problems of arbitrary order and size, and a pseudospectral method for characterizing the nature of the flutter point and its local modal damping gradient. Two variants of the flutter point direct solver are presented, their computational characteristics are compared, and an efficient hybrid method of direct spectral solution and iterative pseudospectral solution is developed. This method is well suited to the analysis of problems arising in reduced-order modeling and preliminary design optimization and has the advantage of computing all the system flutter points and their characteristics with minimal user oversight. The aeroelastic inverse problem, with applications in parameter identification and system optimization, is also shown to be solvable via multiparameter analysis. Extensions and improvements to this new conceptual framework and associated solvers are discussed.
Appropriate Objective Functions for Quantifying Iris Mechanical Properties Using Inverse Finite Element Modeling
Authors: Pant Anup D. , Dorairaj Syril K. , Amini Rouzbeh
Published: March 2018

Quantifying the mechanical properties of the iris is important, as it provides insight into the pathophysiology of glaucoma. Recent ex vivo studies have shown that the mechanical properties of the iris are different in glaucomatous eyes as compared to normal ones. Notwithstanding the importance of the ex vivo studies, such measurements are severely limited for diagnosis and preclude development of treatment strategies. With the advent of detailed imaging modalities, it is possible to determine the in vivo mechanical properties using inverse finite element (FE) modeling. An inverse modeling approach requires an appropriate objective function for reliable estimation of parameters. In the case of the iris, numerous measurements such as iris chord length (CL) and iris concavity (CV) are made routinely in clinical practice. In this study, we have evaluated five different objective functions chosen based on the iris biometrics (in the presence and absence of clinical measurement errors) to determine the appropriate criterion for inverse modeling. Our results showed that in the absence of experimental measurement error, a combination of iris CL and CV can be used as the objective function. However, with the addition of measurement errors, the objective functions that employ a large number of local displacement values provide more reliable outcomes.
Simulation of Airflow in an Idealized Emphysematous Human Acinus
Authors: Dutta Amitvikram , Vasilescu Dragos M. , Hogg James C. , Phillion A. B. , Brinkerhoff J. R.
Published: March 2018

Emphysema is the permanent enlargement of air spaces in the respiratory regions of the lung due to destruction of the inter-alveolar septa. The progressive coalescence of alveoli and alveolar ducts into larger airspaces leads to the disruption of normal airway wall motion and airflow rates within the pulmonary acinus. To contribute to the understanding of the individual effects of emphysema during its earliest stages, computational fluid dynamics (CFD) simulations of airflow in mathematically derived models of the pulmonary acinus were performed. The here generated computational domain consists of two generations of alveolar ducts within the pulmonary acinus, with alveolar geometries approximated as closely packed, 14-sided polygons. Physiologically realistic airflow rates and wall motions were used to study airflow patterns within subsequent generations of alveolar ducts during the inspiratory and expiratory phases of the breathing cycle. The effects of progressive emphysema on the airway wall motion and flow rates were simulated by sequentially removing all alveolar septa within each alveolar duct. Parametric studies were presented to independently assess the relative influence of progressive septal destruction of airway motion and flow rates. The results illustrate that septal destruction lowers the flow resistance through the alveolar ducts but has little influence on the mass transport of oxygen into the alveoli. Septal destruction has a net effect on the flow field by favoring the development of recirculatory flow patterns in individual alveoli.
Optimal Design of Single-Mode Power-Split Hybrid Tracked Vehicles
Authors: Qin Zhaobo , Luo Yugong , Li Keqiang , Peng Huei
Published: March 2018

Hybrid tracked vehicles are common in construction, agriculture, and military applications. Most use a series hybrid powertrain with large motors and operate at a relatively low efficiency. Although some researchers have proposed power-split powertrains, most of these would require an additional mechanism to achieve skid steering. To solve this problem and enhance drivability, a single-mode power-split hybrid powertrain for tracked vehicles with two outputs connected to the left and right tracks is proposed. The powertrain with three planetary gears (PGs) would then be able to control the torque on the two tracks independently and achieve skid steering. This powertrain has three degrees-of-freedom (DOF), allowing for control of the output torques and the engine speed independently from the vehicle running speed. All design candidates with three PGs are exhaustively searched by analyzing the dynamic characteristics and control to obtain the optimal design. Efficient topology design selection with parameter sizing and component sizing is accomplished using the enhanced progressive iteration approach to achieve better fuel economy using downsized components.
Lamb Wave Interaction at Delamination and Debondings Due to Impact Damage in Complex Stiffened CFRP Structures
Authors: Eckstein Benjamin , Moix Bonet Maria , Bach Martin , Fritzen Claus-Peter
Published: March 2018

The increased usage of carbon fiber reinforced plastics (CFRP) for primary aerospace structures involves dealing with the susceptibility of composite laminates to impact loads as well as the occurrence of barely visible impact damages. One special case among impact sources is the so-called blunt impact, which may cause damage primarily to the internal structure. Therefore, the assessment of debonding of stiffening elements in CFRP structures poses an attractive application case for structural health monitoring by guided ultrasonic waves. Wave propagation phenomena at impact damages as well as the signal processing utilized to extract a damage related feature (i.e., damage index (DI)) contribute to the sensitivity, and thus, to the reliability of structural health monitoring (SHM) systems. This work is based on data from the EU-funded project SARISTU, where a generic CFRP door surrounding fuselage panel with an integrated sensor network has been built and tested by introducing a large number of impact damages. Wave interaction of delaminations and stringer debondings of different size and morphology in omega-stringer stiffened structures are examined to highlight the factors contributing to the sensitivity. Common damage indicator formulations for the use with imaging algorithms, such as the reconstruction algorithm for the probabilistic inspection of damage (RAPID), are applied on data from various damage cases. Furthermore, the difference in detectability of delaminations and debondings as well as the implications on imaging algorithms is examined.
Analysis of the Effect of Beam Divergence Angle on Back-Streaming Electron Region in Ion Source for EAST-Neutral Beam Injection
Authors: Chundong Hu , Mingshan Wu , Yahong Xie , Jianglong Wei , Ling Yu
Published: March 2018

During the process of beam extraction in positive ion source under high voltage region, a large number of electrons are produced in the gaps of grids. After back-streaming acceleration, these electrons go back to arc chamber or impinge grids and then heat back plate or grids, which are harmful for the safety of ion source. Under the situation of poor beam extraction optics, a large part of the primary beam ions bombard the surface of suppressor grid (SG). And this process produces a large number of electrons. Due to the huge extracted voltage, the secondary electron emission coefficient of the SG surface is also high. As a result, the grids' current grows. According to the measurement of the current of SG and the calculation of the perveance of the corresponding shoot, the effect of ion beam divergence angle on back-streaming electrons can be analyzed. When the beam divergence angle increases, the number of back-streaming electrons increases rapidly, and grids' current changes significantly, especially the current of gradient grid and SG. The results can guide the parameters operating on the ion source for Experimental Advanced Superconducting Tokamak-neutral beam injection (EAST-NBI) and find the reasonable operation interval of perveance and to ensure the safety and stable running of the ion source, which has great significance on the development of long pulse, high power ion source.
Numerical Study on Inelastic Seismic Design of Piping Systems Using Damping Effect Based on Elastic–Plastic Property of Pipe Supports
Authors: Maekawa Akira , Takahashi Tsuneo
Published: March 2018

This study describes inelastic seismic design of piping systems considering the damping effect caused by elastic–plastic property of a pipe support which is called an elastic–plastic support. Though the elastic–plastic support is proposed as inelastic seismic design framework in the Japan Electric Association code for the seismic design of nuclear power plants (JEAC4601), the seismic responses of the various piping systems with the support are unclear. In this study, the damping coefficient of a piping system is focused on, and the relation between seismic response of the piping system and elastic–plastic behavior of the elastic–plastic support was investigated using nonlinear time history analysis and complex eigenvalue analysis. The analysis results showed that the maximum seismic response acceleration of the piping system decreased largely in the area surrounded by pipe elbows including the elastic–plastic support which allowed plastic deformation. The modal damping coefficient increased a maximum of about sevenfold. Furthermore, the amount of the initial stiffness of the elastic–plastic support made a difference in the increasing tendency of the modal damping coefficient. From the viewpoint of the support model in the inelastic seismic design, the reduction behavior for the seismic response of the piping system was little affected by the 10% variation of the secondary stiffness. These results demonstrated the elastic–plastic support is a useful inelastic seismic design of piping systems on the conditions where the design seismic load is exceeded extremely.
Enhancement of Film Cooling Effectiveness Using Rectangular Winglet Pair
Authors: Jindal Prakhar , Agarwal Shubham , Sharma R. P. , Roy A. K.
Published: March 2018

This study deals with the film cooling enhancement in a combustion chamber by the use of rectangular winglet vortex generators (VGs). Rectangular winglet pair (RWP) in both the common-flow up and the common-flow down configuration is installed upstream of a coolant injection hole on the lower chamber wall. A three-dimensional numerical approach with complete solution of Navier–Stokes (NS) equations closed by the k–ɛ turbulence model is used for analyzing the effect of VG installation on film cooling effectiveness enhancement. The effect of RWP orientation is investigated to deduce the best configuration which is then optimized in terms of its geometrical parameters including its upstream distance from the hole and the angle it makes with the incoming flow. Results obtained show that a RWP located upstream of the coolant hole in common-flow down configuration gives the best effectiveness enhancement with certain other geometrical parameters specified. A novel “mushroom” adiabatic distribution scheme for film cooling effectiveness and temperature has been discussed in the paper. This characteristic scheme is developed as a result of RWPs' vortices interaction with the coolant inlet jet and the hot mainstream flow. A detailed discussion of the mechanisms and the flow field properties underlying the effectiveness enhancement and other phenomenon observed has also been presented in the paper.
Detailed Description of Electro-Osmotic Effect on an Encroaching Fluid Column Inside a Narrow Channel
Authors: Sumanasekara Rakhitha Udugama , Bhattacharya Sukalyan
Published: March 2018

This paper uses eigenexpansion technique to describe electro-osmotic effect on unsteady intrusion of a viscous liquid driven by capillary action in a narrow channel. It shows how the dynamics can be manipulated by imposing an electric field along the flow direction in the presence of free charges. Similar manipulation can generate controlled transiency in motion of a complex fluid in a tube by nondestructive forcing leading to efficient rheological measurement. Existing theories analyze similar phenomena by accounting for all involved forces among which the viscous contribution is calculated assuming a steady velocity profile. However, if the transport is strongly transient, a new formulation without an underlying quasi-steady assumption is needed for accurate prediction of the time-dependent penetration. Such rigorous mathematical treatment is presented in this paper where an eigenfunction expansion is used to represent the unsteady flow. Then, a system of ordinary differential equations is derived from which the unknown time-dependent amplitudes of the expansion are determined along with the temporal variation in encroached length. The outlined methodology is applied to solve problems with both constant and periodically fluctuating electric field. In both cases, simplified and convenient analytical models are constructed to provide physical insight into numerical results obtained from the full solution scheme. The detailed computations and the simpler reduced model corroborate each other verifying accuracy of the former and assuring utility of the latter. Thus, the theoretical findings can render a new rheometric technology for effective determination of fluid properties.
Characterization and Tribological Behavior of TiAlN/TiAlCN Multilayer Coatings
Authors: Lei Zhefeng , Zhu Xiaodong , Li Yanhuai , Song Zhongxiao , Liu Haiping , Fu Yong Qing
Published: March 2018

Effects of partial pressure of methane on deposition rate, hardness, bonding strength and friction coefficient of TiAlN/TiAlC0.37N0.63 multilayer coating were investigated. The TiAlN coating was deposited at a N2 flow rate of 70 sccm, and TiAlC0.37N0.63 coating were deposited at a N2 flow rate of 35 sccm and a CH4 flow rate of 35 sccm. TiAlN/TiAlC0.37N0.63 multilayer coatings with different modulation periods but the same total thickness of 3.56 μm were deposited on high speed steel (HSS) substrates using multi-arc ion plating technology. Microhardness and tribological measurement show that the multilayer coating with a modulating ratio of 1:1 and a modulation period of 68 nm had a hardness of 2793.9 HV0.10, an excellent bonding strength of 52 N, and the minimum friction coefficient of 0.46 and a relatively low wear rate.
Cycle-to-Cycle Feedback for Combustion Control of Spark Advance at the Misfire Limit
Authors: Maldonado Bryan P. , Stefanopoulou Anna G.
Published: March 2018

At a given speed and load, the spark advance (SA) is tuned to reach the maximum brake torque (MBT) timing to maximize efficiency. The use of exhaust gas recirculation (EGR) can further improve fuel economy (FE) at the same speed and load. As EGR increases, MBT moves toward a more advanced timing that can be limited by the high variability in the combustion process, reflected in unacceptable torque fluctuations. This variability is rapidly increased by the random occurrence of partial burns and/or misfires. In order to operate close to the misfire limit, a stochastic misfire controller has been designed to momentarily move from an undesired to an allowable misfire rate, without significantly increasing variability in the combustion process. Control-oriented models for the combustion process and misfire events are discussed. Simulation of the closed-loop system shows that the feedback misfire controller, on average, stays closer to the misfire limit than a more conventional controller designed to react when a misfire is detected.
The Association of Health-Related Fitness and Chronic Absenteeism Status in New York City Middle School Youth
Authors: D’Agostino Emily M. , Day Sophia E. , Konty Kevin J. , Larkin Michael , Saha Subir , Wyka Katarzyna
Published: March 2018

Background: Extensive research demonstrates the benefits of fitness on children’s health and academic performance. Although decreases in health-related fitness may increase school absenteeism, multiple years of prospective, child-level data are needed to examine whether fitness changes predict subsequent chronic absenteeism status. Methods: Six cohorts of New York City public school students were followed from grades 5–8 (2006/2007–2012/2013; N = 349,381). A longitudinal 3-level logistic generalized linear mixed model with random intercepts was used to test the association of individual children’s changes in fitness and 1-year lagged chronic absenteeism. Results: The odds of chronic absenteeism increased 27% [odds ratio (OR) 95% confidence interval (CI), 1.25–1.30], 15% (OR 95% CI, 1.13–1.18), 9% (OR 95% CI, 1.07–1.11), and 1% (OR 95% CI, 0.98–1.04), for students who had a >20% decrease, 10%–20% decrease, <10% increase or decrease, and 10%–20% increase in fitness, respectively, compared with >20% fitness increase. Conclusion: These findings contribute important longitudinal evidence to a cross-sectional literature, demonstrating reductions in youth fitness may increase absenteeism. Given only 25% of youth aged 12–15 years achieve the recommended daily 60 minutes or more of moderate to vigorous physical activity, future work should examine the potential for youth fitness interventions to reduce absenteeism and foster positive attitudes toward lifelong physical activity.
Suppression of diabetes by accumulation of non–islet-specific CD8
+
effector T cells in pancreatic islets
Authors: Christoffersson Gustaf , Chodaczek Grzegorz , Ratliff Sowbarnika S. , Coppieters Ken , von Herrath Matthias G.
Published: March 2018

Non–antigen-specific CD8
+
T cells act as local suppressors to limit autoimmunity and viral inflammation.
Human Group C Rotavirus VP8*s Recognize Type A Histo-Blood Group Antigens as Ligands
Authors: Sun Xiaoman , Wang Lihong , Qi Jianxun , Li Dandi , Wang Mengxuan , Cong Xin , Peng Ruchao , Chai Wengang , Zhang Qing , Wang Hong , Wen Hongling , Gao George F. , Tan Ming , Duan Zhaojun
Published: March 2018

Group/species C rotaviruses (RVCs) have been identified as important pathogens of acute gastroenteritis (AGE) in children, family-based outbreaks, as well as animal infections. However, little is known regarding their host-specific interaction, infection, and pathogenesis. In this study, we performed serial studies to characterize the function and structural features of a human G4P[2] RVC VP8* that is responsible for the host receptor interaction. Glycan microarrays demonstrated that the human RVC VP8* recognizes type A histo-blood group antigens (HBGAs), which was confirmed by synthetic glycan-/saliva-based binding assays and hemagglutination of red blood cells, establishing a paradigm of RVC VP8*-glycan interactions. Furthermore, the high-resolution crystal structure of the human RVC VP8* was solved, showing a typical galectin-like structure consisting of two β-sheets but with significant differences from cogent proteins of group A rotaviruses (RVAs). The VP8* in complex with a type A trisaccharide displays a novel ligand binding site that consists of a particular set of amino acid residues of the C-D, G-H, and K-L loops. RVC VP8* interacts with type A HBGAs through a unique mechanism compared with that used by RVAs. Our findings shed light on the host-virus interaction and the coevolution of RVCs and will facilitate the development of specific antivirals and vaccines.

IMPORTANCE
Group/species C rotaviruses (RVCs), members of
Reoviridae
family, infect both humans and animals, but our knowledge about the host factors that control host susceptibility and specificity is rudimentary. In this work, we characterized the glycan binding specificity and structural basis of a human RVC that recognizes type A HBGAs. We found that human RVC VP8*, the rotavirus host ligand binding domain that shares only ∼15% homology with the VP8* domains of RVAs, recognizes type A HBGA at an as-yet-unknown glycan binding site through a mechanism distinct from that used by RVAs. Our new advancements provide insights into RVC-cell attachment, the critical step of virus infection, which will in turn help the development of control and prevention strategies against RVs.
Effectiveness of a chronic obstructive pulmonary disease integrated care pathway in a regional health system: a propensity score matched cohort study
Authors: Wu Christine Xia , Hwang Chi Hong , Tan Woan Shin , Tai Kai Pik , Kwek Lynette Siang Lim , Chee Thong Gan , Choo Yee Mun , Phng Francis Wei Loong , Chua Gerald Seng Wee
Published: March 2018

Objective

The chronic obstructive pulmonary disease (COPD) integrated care pathway (ICP) programme was designed and implemented to ensure that the care for patients with COPD is comprehensive and integrated across different care settings from primary care to acute hospital and home. We evaluated the effectiveness of the ICP programme for patients with COPD.

Design, setting and participants

A retrospective propensity score matched cohort study was conducted comparing differences between programme enrolees and propensity-matched non-enrolees in a Regional Health System in Singapore. Data on patients diagnosed with COPD who enrolled in the programme (n=95) and patients who did not enrol (n=6330) were extracted from the COPD registry and hospital administrative databases. Enrolees and non-enrolees were propensity score matched.

Outcome measures

The risk of COPD hospitalisations and COPD hospital bed days savings were compared between the groups using a difference-in-difference strategy and generalised estimating equation approach. Adherence with recommended care elements for the COPD-ICP group was measured quarterly at baseline and during a 2-year follow-up period.

Results

Compared with non-enrolees, COPD hospitalisation risk for ICP programme enrolees was significantly lower in year 2 (incidence rate ratio (IRR): 0.73; 95% CI 0.54 to 1.00). Similarly, COPD hospital bed days was significantly lower for enrolees in year 2 (IRR: 0.78; 95% CI 0.64 to 0.95). ICP programme patients had sustained improvements in compliance with all recommended care elements for patients with COPD. The overall all-or-none care bundle compliance rate had improved from 28% to 54%.

Conclusion

The study concluded that the COPD-ICP programme was associated with reductions in COPD hospitalisation risk and COPD health utilisation in a 2-year follow-up period.
A systematic review of interventions to support the careers of women in academic medicine and other disciplines
Authors: Laver Kate E , Prichard Ivanka J , Cations Monica , Osenk Ivana , Govin Kay , Coveney John D
Published: March 2018

Objective

To summarise quantitative evaluations of interventions designed to support the careers of women in academia of any discipline.

Method

A systematic search of English entries in PubMed, CINAHL and Google Scholar was conducted in September 2017. Methodological quality of the studies was independently assessed by two authors using the Joanna Briggs Institute quality appraisal checklists. Meta-analysis was not possible due to heterogeneity in methods and outcomes; results were synthesised and displayed narratively.

Results

Eighteen eligible studies were identified, mostly evaluating programmes in academic medicine departments. The most common interventions were mentoring, education, professional development and/or networking programmes. All programmes took a ‘bottom-up’ approach in that women were responsible for opting into and devoting time to participation. Study quality was low overall, but all studies reported positive outcomes on at least one indicator. Most often this included improvements in self-rated skills and capabilities, or satisfaction with the programme offered. Results regarding tangible outcomes were mixed; while some studies noted improvements in promotion, retention and remuneration, others did not.

Conclusions

This review suggests that targeted programmes have the potential to improve some outcomes for women in academia. However, the studies provide limited high-quality evidence to provide information for academic institutions in terms of the best way to improve outcomes for women in academia. The success of an intervention appears to be undermined when it relies on the additional labour of those it is intending to support (ie, ‘bottom-up’ approaches). As such, academic institutions should consider and evaluate the efficacy of ‘top-down’ interventions that start with change in practice of higher management.
Impact of a commercial order entry system on prescribing errors amenable to computerised decision support in the hospital setting: a prospective pre-post study
Authors: Pontefract Sarah K , Hodson James , Slee Ann , Shah Sonal , Girling Alan J , Williams Robin , Sheikh Aziz , Coleman Jamie J
Published: March 2018

Background

In this UK study, we investigated the impact of computerised physician order entry (CPOE) and clinical decision support (CDS) implementation on the rate of 78 high-risk prescribing errors amenable to CDS.

Methods

We conducted a preintervention/postintervention study in three acute hospitals in England. A predefined list of prescribing errors was incorporated into an audit tool. At each site, approximately 4000 prescriptions were reviewed both pre-CPOE and 6 months post-CPOE implementation. The number of opportunities for error and the number of errors that occurred were collated. Error rates were then calculated and compared between periods, as well as by the level of CDS.

Results

The prescriptions of 1244 patients were audited pre-CPOE and 1178 post-CPOE implementation. A total of 28 526 prescriptions were reviewed, with 21 138 opportunities for error identified based on 78 defined errors. Across the three sites, for those prescriptions where opportunities for error were identified, the error rate was found to reduce significantly post-CPOE implementation, from 5.0% to 4.0% (P<0.001). CDS implementation by error type was found to differ significantly between sites, ranging from 0% to 88% across clinical contraindication, dose/frequency, drug interactions and other error types (P<0.001). Overall, 43/78 (55%) of the errors had some degree of CDS implemented in at least one of the hospitals.

Conclusions

Implementation of CPOE with CDS was associated with clinically important reductions in the rate of high-risk prescribing errors. Given the pre-post design, these findings however need to be interpreted with caution. The occurrence of errors was found to be highly dependent on the level of restriction of CDS presented to the prescriber, with the effect that different configurations of the same CPOE system can produce very different results.
Improving medication adherence in patients with cardiovascular disease: a systematic review
Authors: Fuller Rosemary Hines , Perel Pablo , Navarro-Ruan Tamara , Nieuwlaat Robby , Haynes Robert Brian , Huffman Mark D
Published: March 2018

Objective

To evaluate and compare the effect of interventions for improving adherence to medications for atherosclerotic cardiovascular disease (ASCVD) secondary prevention.

Methods

We extracted eligible trials from a 2014 Cochrane systematic review on adherence for any condition. We updated the search from CENTRAL, Medline, Embase, PsycINFO, CINAHL, Sociological Abstracts and trial registers through November 2016. Study reports needed to be from a randomised controlled trial, incorporate participants identified as having ASCVD and interventions aimed at improving adherence to medicines for secondary prevention of ASCVD and measure both adherence and a clinical outcome. Two reviewers independently determined the eligibility of studies, extracted data and conducted a narrative synthesis.

Results

We identified 17 trials (n=17 448 participants). Most trials had high risk of bias in at least one domain. The intervention group adherence rates ranged from 44%to99% and the comparator group adherence rates ranged from 13% to 96%. Three distinct interventions reported improvements in both adherence and clinical outcomes: short message service (65% vs 13% of participants with high adherence in the intervention vs control group), a fixed-dose combination pill (86% vs 65% adherence, risk ratio of being adherent, 1.33; 95% CI 1.26 to 1.41) and a community health worker-based intervention (97% in the intervention group compared with 92% in the control group; OR=2.62, 95% CI 1.32 to 5.19).

Conclusions

We identified three interventions that demonstrated improvements in adherence and clinical outcomes. Ongoing, longer-term trials will help determine whether short-term changes in adherence can be maintained and lead to differences in clinical events.
Take home messages with cases from focused update on echocardiographic assessment of aortic stenosis
Authors: Hung Judy , Klassen Sheila Liu , Bermejo Javier , Chambers John Boyd
Published: March 2018

Echocardiography plays an important role in the assessment of valvular aortic stenosis. Updated recommendations focusing on a stepwise approach to evaluating aortic stenosis have recently been published by the European Association of Cardiovascular Imaging and the American Society of Echocardiography. This review uses illustrative cases to demonstrate technical aspects of aortic stenosis assessment and use of the new proposed classification scheme for aortic stenosis. Key points from the updated recommendations reviewed in this paper are: (1) technical considerations and sources of error in measurement of peak velocity, mean aortic valve gradient and aortic valve area by continuity equation. (2) Application of flow status using indexed left ventricular stroke volume to distinguish patients with low gradients and a low calculated aortic valve area. (3) Use of low-dose dobutamine stress echocardiography in patients with low ejection fraction. (4) Application of the new classification scheme and review of algorithm use for echocardiographic evaluation of severe aortic stenosis. Improved understanding of how to handle unmatched variables and adopting an integrated approach to determine severity is central to guiding the clinician’s management of aortic stenosis.
Increase in fluoroscopic radiation dose in successive sessions of multistage Onyx embolization of brain arteriovenous malformations compared with the first session
Authors: Sheen Jae Jon , Jiang Yuan Yuan , Kim Young Eun , Maeng Jun Young , Kim Tae-Il , Lee Deok Hee
Published: March 2018

Background and purpose

Onyx embolization is a treatment for brain arteriovenous malformations (AVMs). However, multistage embolization usually involves the presence of radiodense Onyx cast from the previous sessions, which may influence the fluoroscopic radiation dose. We compared the fluoroscopic dose between the initial and final embolization sessions.

Materials and method

From January 2014 to September 2016, 18 patients underwent multistage Onyx embolization (more than twice) for brain AVMs. The total fluoroscopic duration (minutes), dose–area product (DAP, Gy×cm2), and cumulative air kerma (CAK, mGy) of both the frontal and lateral planes were obtained. We compared the frontal and lateral fluoroscopic dose rates (dose/time) of the final embolization session with those of the initial session. The relationship between the injected Onyx volume and radiation dose was tested.

Results

The initial and final procedures on the frontal plane showed significantly different fluoroscopic dose rates (DAP: initial 0.668 Gy×cm2/min, final 0.848 Gy×cm2/min, P=0.02; CAK: initial 12.7 mGy/min, final 23.1 mGy/min, P=0.007). Those on the lateral plane also showed a similar pattern (DAP: initial 0.365 Gy×cm2/min, final 0.519 Gy×cm2/min, P=0.03; CAK: initial 6.2 mGy/min, final 12.9 mGy/min, P=0.01). The correlation between the cumulative Onyx volume (vials) and radiation dose ratio of both planes showed an increasing trend (rho 0.4325–0.7053; P=0.0011–0.0730).

Conclusion

Owing to the automatic exposure control function during fluoroscopy, successive Onyx embolization procedures increase the fluoroscopic radiation dose in multistage brain AVM embolization because of the presence of radiodense Onyx mass.
Investigations of the physical nature of the emergence and spread of relativistic astrophysical jets
Authors: Belyaev Vadim S. , Matafonov Anatoly P. , Zagreev Boris V.
Published: March 2018

A series of experiments were carried out at the TSNIIMASH laser facility “Neodym” with a radiation power of 10 TW and an intensity of [Formula: see text]–[Formula: see text][Formula: see text]W/cm2 to simulate the formation and development of astrophysical relativistic jets. It was shown that proton beams are emitted symmetrically in the forward and backward directions to the normal of the target surface. The maximum energy of fast protons and electrons was 5 and 8[Formula: see text]MeV, respectively. At energies in the 0.8–1.7[Formula: see text]MeV range, the ring structures of proton beams are clearly distinguishable with an angular divergence in the range of 3–250. The numerical magnetohydrodynamic calculations have shown that such laboratory experiments can simulate the formation of astrophysical jets with an anomalously small divergence. Moreover, such a plasma stream can form a distinct circular structure. These structures also can be explained as Alfven vortex solitons formed under the conditions of a quasi-stationary superstrong ([Formula: see text]100 MG) magnetic field spontaneously generated in laser produced plasma. It is shown that this model can be used as a model of astrophysical relativistic jets.