bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for a physiological role of pulmonary arterial baroreceptors in sympathetic neural activation in healthy humans
Authors: Simpson Lydia L. , Meah Victoria L. , Steele Andrew , Thapamagar Suman , Gasho Christopher , Anholm James D. , Drane Aimee L. , Dawkins Tony G. , Busch Stephen A. , Oliver Samuel J. , Lawley Justin S. , Tymko Michael M. , Ainslie Phillip N. , Steinback Craig D. , Stembridge Mike , Moore Jonathan P.
Published: January 2020

Key points

In an anaesthetised animal model, independent stimulation of baroreceptors in the pulmonary artery elicits reflex sympathoexcitation.

In humans, pulmonary arterial pressure is positively related to basal muscle sympathetic nerve activity (MSNA) under conditions where elevated pulmonary pressure is evident (e.g. high altitude); however, a causal link is not established.

Using a novel experimental approach, we demonstrate that reducing pulmonary arterial pressure lowers basal MSNA in healthy humans.

This response is distinct from the negative feedback reflex mediated by aortic and carotid sinus baroreceptors when systemic arterial pressure is lowered.

Afferent input from pulmonary arterial baroreceptors may contribute to sympathetic neural activation in healthy lowland natives exposed to high altitude.

In animal models, distension of baroreceptors located in the pulmonary artery induces a reflex increase in sympathetic outflow; however, this has not been examined in humans. Therefore, we investigated whether reductions in pulmonary arterial pressure influenced sympathetic outflow and baroreflex control of muscle sympathetic nerve activity (MSNA). Healthy lowlanders (n = 13; 5 females) were studied 4–8 days following arrival at high altitude (4383 m; Cerro de Pasco, Peru), a setting that increases both pulmonary arterial pressure and sympathetic outflow. MSNA (microneurography) and blood pressure (BP; photoplethysmography) were measured continuously during ambient air breathing (Amb) and a 6 min inhalation of the vasodilator nitric oxide (iNO; 40 ppm in 21% O2), to selectively lower pulmonary arterial pressure. A modified Oxford test was performed under both conditions. Pulmonary artery systolic pressure (PASP) was determined using Doppler echocardiography. iNO reduced PASP (24 ± 3 vs. 32 ± 5 mmHg; P < 0.001) compared to Amb, with a similar reduction in MSNA total activity (1369 ± 576 to 994 ± 474 a.u min−1; P = 0.01). iNO also reduced the MSNA operating point (burst incidence; 39 ± 16 to 33 ± 17 bursts·100 Hb−1; P = 0.01) and diastolic operating pressure (82 ± 8 to 80 ± 8 mmHg; P < 0.001) compared to Amb, without changing heart rate (P = 0.6) or vascular–sympathetic baroreflex gain (P = 0.85). In conclusion, unloading of pulmonary arterial baroreceptors reduced basal sympathetic outflow to the skeletal muscle vasculature and reset vascular–sympathetic baroreflex control of MSNA downward and leftward in healthy humans at high altitude. These data suggest the existence of a lesser‐known reflex input involved in sympathetic activation in humans.
Energy Management of Microgrid Considering Renewable Energy Sources and Electric Vehicles Using the Backtracking Search Optimization Algorithm
Authors: Li Yong , Mohammed Salim Qadir , Nariman Goran Saman , Aljojo Nahla , Rezvani Alireza , Dadfar Sajjad
Published: January 2020

Different distributed generation (DG) technologies, active loads, and storage devices create an independent microgrid (MG). Scheduling of an MG is an important issue in renewable energy sources (RESs) based systems. In this paper, MGs include RESs, plug-in hybrid electric vehicles (PHEVs), and electrical energy storage systems. The proposed scheduling framework utilizes the Monte Carlo simulation (MCS) to characterize the uncertain parameters of PHEVs and RESs. Three different charging strategies are investigated for modeling the impact of different behaviors of PHEVs in MGs. These schemes are smart, controlled, and uncontrolled charging. Due to the nonlinear feature of the suggested optimization problem, it needs an efficient optimization tool to tackle the problem appropriately. So, this paper uses the backtracking search optimization (BSO) algorithm for the short-term scheduling of an MG. The proper performance of the offered scheme is investigated in two scenarios with different time horizons. The BSO algorithm and other optimization algorithms are used for comparing the results to verify the presented method in solving the energy management problem of the MGs.
Phenomena Based Model for Predicting Ignition Probability for Gas-Turbine Combustors
Authors: Shrivastava Sourabh , Nakod Pravin
Published: January 2020

With the ever-increasing drive to design more clean and efficient gas-turbine combustors, operational conditions of the civil aero engines have been drifting towards leaner fuel-air ratio configurations. Such configurations demand careful designing of engines, keeping multiple conflicting goals in mind. One of the critical aspects is keeping the combustor designs capable of giving excellent Relight performance under all susceptible conditions.

High-fidelity simulation methods can provide comprehensive insights about Relight process but at the same time becomes computationally prohibitive to perform relevant studies of ignition-probability for real-life gas-turbine combustors. Another family of ‘Particle-based/Cellular Automation’ models comes handy to bridge this gap, as they can provide reasonable information about ignition probability for a given spark location and flow-condition, with a much lesser computational cost.

This work reviews some of the phenomena-based models proposed in recent pasts and uses one of the flame-particle based models to validate standard experimental work published for diffusion flames involving gaseous fuels. This method is extended to improve the visualization aspect of representative flame and to track independent flares from multiple spark locations in a single setup.

The validated approach is tested on five swirled injectors designed by CORIA in the context of Knowledge for Ignition, Acoustics, and Instabilities (KIAI) project, to evaluate its applicability in predicting ignition sequence and ignition probability for complex configurations. Implemented particle-based model found to predict reasonably good results for all evaluated configurations.
CFD Simulation of Ducted Dual Rotor Wind Turbine for Small-Scale Applications
Authors: Mohamed Amr , El-Baz Ahmed , Mahmoud Nabil , Hamed Ashraf , El-kohly Ahmed
Published: January 2020

Due to growing needs for energy in our life, research in the wind energy field has increased significantly. There has been global concern towards the development of smart techniques and devices that could optimize the energy conversion and maximize the output power from the wind. Investigating such alternative solutions are required in order to meet the continuous increase in the power demand.

The Dual Rotor Wind Turbine system (DRWT) offers higher energy extraction rates from the wind. In the present study, it is proposed to utilize the dual rotor configuration in a ducted system using wind lens in order to enable its application in regions of low wind speeds. The aerodynamic performance of ducted dual rotor wind turbine is investigated using CFD to solve three dimensional, turbulent-steady incompressible flow equations, using the k-ε Realizable and k-ω shear stress transport (SST) turbulence models. Several difficulties due to complexity of geometry and meshing requirements have been encountered. Mesh independence study was conducted to ensure the accuracy and validate the results. Power curves were obtained, detailed investigation of the wind turbine performance in different configurations are highlighted in order to explore the benefit and effect of each configuration to the output power. The final results of combined configuration for dual rotor wind turbine (DRWT) with lens show a considerable improvement to the performance of wind turbine over wide range of wind speeds.
Analysis of Cracked Rotor With Gyroscopic Effects Supported on Textured Journal Bearings
Authors: Shravankumar C. , Jegadeesan K. , Rao T. V. V. L. N.
Published: January 2020

This paper present the analysis of a cracked rotor shaft with an offset disc attached to it and mounted on textured journal bearings. The bearings are modelled using linearized stiffness and damping coefficients, both direct and cross-coupled. The shaft and disc are modelled using finite element theory. The shaft and disc masses, stiffnesses and their gyroscopic effects are considered. The crack is modeled based on fracture mechanics approach. The rotor dynamic modelling and analysis of the system considering the effect of crack geometry is carried out to obtain the system whirl frequencies. The system is represented in reduced order state-space form and its critical speeds are obtained by plotting the Campbell diagram.
Turbine Rear Frame Design for an Aero Derivative Gas Turbine
Authors: Chippa Anil Kumar , Babu Santhana G. , Federico Casadio , Pittella Gianfranco
Published: January 2020

The design of Free Power Turbine (FPT) & Aero-derivative Engine core which enables reduced foot print, high efficiency, quick engine swap, and less cost of ownership is in times of need for LNG customers. FPT as the name states, Free spinning Turbine, facilitates the gas turbine to operate at part load with varying speed & power while maintaining high efficiency and gearbox less architecture. This gas turbine is suited for both mechanical drive & also power generation applications. This paper describes the experience of Baker Hughes, a GE Company (BHGE) in design of Turbine Rear Frame (TRF) for such an Aero-derivative gas turbine which has an FPT architecture complying to the product requirement needs. The main functional requirements of TRF is to enable the hot flow path to recover back pressure, embedded reverse thrust pressurized air, bearing sump air, oil & vent piping, and structural stiffness to with stand normal operating & emergency bearing loads. Contribution of temperature gradients related to gas turbine operating profile and corresponding cooling flows on TRF is an important aspect which would drive the structural integrity and deciding factor for fatigue life of the whole configuration. During designing the TRF and its subcomponents, tradeoff study has been conducted for the strut configurations, cooling flow circuits and are evaluated against the structural integrity of the component. Such aspects on how various configurations are traded off would be dealt in this paper, with an added aspect of Manufacturability & Cost variations.
Modal Analysis and Dynamic Responses of a Hysteretically Damped Axle Shaft With a Transverse Crack
Authors: Shravankumar C. , Sarda Yash K. , Thamarai Selvan V.
Published: January 2020

An axle shaft supports rotating elements, and is fitted to the housing by means of bearings. It mostly does not transmit torque, with exceptions such as in train axles. Non-rotating axles are subjected to bending moments due to dynamic transverse loads. Axles such as in automobiles are marked with occasional failures due to fatigue cracks, which can prove serious, if the cracks are not detected early. Vibration based condition monitoring is the field concerned with crack detection based on the dynamic responses of the system. In this light, the present paper discusses the vibration analysis of a cracked axle. The cracked shaft is modelled using finite element method, for transverse vibration conditions. The shaft is modelled based on Euler-Bernoulli theory for bending, while the crack is modelled based on fracture mechanics approach. After modelling, modal analysis of the system is carried out, with the consideration of proportional hysteretic damping. The Eigen value problem provides the natural frequencies and mode shapes. The Frequency Response Functions (FRF’s) magnitude and phase plots are obtained, from which the natural frequencies and structural damping loss factors can be calculated. Further, the free vibration and forced vibration system time responses are obtained, using numerical integration methods. The corresponding responses in frequency domain are obtained using Fast Fourier Transformation (FFT). The FRF’s and dynamic responses of the shaft without and with crack are comparatively studied. The study provides the platform for condition monitoring of shaft cracks.
Effect of Deaerator Parameters on Simple and Reheat Gas/Steam Combined Cycle With Different Cooling Medium
Authors: Maheshwari Mayank , Singh Onkar
Published: January 2020

Performance of gas/steam combined cycle power plants relies upon the performance exhibited by both gas based topping cycle and steam based bottoming cycle. Therefore, the measures for improving the performance of the gas turbine cycle and steam bottoming cycle eventually result in overall combined cycle performance enhancement. Gas turbine cooling medium affects the cooling efficacy. Amongst different parameters in the steam bottoming cycle, the deaerator parameter also plays its role in cycle performance. The present study analyzes the effect of deaerator’s operating pressure being varied from 1.6 bar to 2.2 bar in different configurations of simple and reheat gas/steam combined cycle with different cooling medium for fixed cycle pressure ratio of 40, turbine inlet temperature of 2000 K and ambient temperature of 303 K with varying ammonia mass fraction from 0.6 to 0.9. Analysis of the results obtained for different combined cycle configuration shows that for the simple gas turbine and reheat gas turbine-based configurations, the maximum work output of 643.78 kJ/kg of air and 730.87 kJ/kg of air respectively for ammonia mass fraction of 0.6, cycle efficiency of 54.55% and 53.14% respectively at ammonia mass fraction of 0.7 and second law efficiency of 59.71% and 57.95% respectively at ammonia mass fraction of 0.7 is obtained for the configuration having triple pressure HRVG with ammonia-water turbine at high pressure and intermediate pressure and steam turbine operating at deaerator pressure of 1.6 bar.
Scale-Adaptive Simulations of High-Pressure Turbine Guide Vane
Authors: Wang Guoliang , Zhong Dongdong , Ge Ning , Yang Rongfei
Published: January 2020

The flow inside a high-pressure turbine is a fully 3-D, unsteady flow, which has a great influence on the aero-thermal performance and structural strength of high-pressure turbines. In order to better understand the flow mechanism and guide the design of modern aero engines, the basic flow characteristics of transonic turbine are investigated in the present study. A modified scale-adaptive simulation (SAS) technique based on the shear stress transport (SST) turbulence model is applied here. Two test cases are carried out to assess the capability of the current model in predicting complex turbulent flows. The results show that the statistical parameters and flow structures of the modified SAS model are in good agreement with the large eddy simulation (LES) result and the experimental data, where the calculation time is significantly reduced compared to LES. In summary, the modified SAS method has demonstrated an excellent spatial resolution in unsteady simulations of turbomachinery, which shows the potential to be applied to realistic engineering applications.
Effect of Tubercles Shape on the Aerodynamic Performance of a Wind Turbine Blade Operating at Low Reynolds Number
Authors: Swasthika D. S. , Varpe Mahesh K.
Published: January 2020

In wind turbine blade, most of the losses occurs due to aerodynamic losses in the post stall operating condition. Adoption of the blade leading edge tubercles improves the post stall aerodynamic performance. Nevertheless the geometric parameters of the protuberance play a vital role in influencing the aerodynamic performance, it is possible that shape of the protuberance may also have aerodynamic significance. In this paper different types of tubercle shapes are adopted on the blade leading edge to study the improvement in the aerodynamic performance. Each of the shape is studied for different AOA operating at Reynolds number of 3 × 105. The results revealed that the shape of the tubercles also influence the flow which affects the performances.
Identification of Wake Convection and Flow Outline in the Interface Region of Blade Rows With Axial Gap in a Counter Rotating Turbine
Authors: Subbarao Rayapati , Govardhan M.
Published: January 2020

In a Counter Rotating Turbine (CRT), the stationary nozzle is trailed by two rotors that rotate in the opposite direction to each other. Flow in a CRT stage is multifaceted and more three dimensional, especially, in the gap between nozzle and rotor 1 as well as rotor 1 and rotor 2. By varying this gap between the blade rows, the flow and wake pattern can be changed favorably and may lead to improved performance. Present work analyzes the aspect of change in flow field through the interface, especially the wake pattern and deviation in flow with change in spacing. The components of turbine stage are modeled for different gaps between the components using ANSYS® ICEM CFD 14.0. Normalized flow rates ranging from 0.091 to 0.137 are used. The 15, 30, 50 and 70% of the average axial chords are taken as axial gaps in the present analysis. CFX 14.0 is used for simulation. At nozzle inlet, stagnation pressure boundary condition is used. At the turbine stage or rotor 2 outlet, mass flow rate is specified. Pressure distribution contours at the outlets of the blade rows describe the flow pattern clearly in the interface region. Wake strength at nozzle outlet is more for the lowest gap. At rotor 1 outlet, it is less for x/a = 0.3 and increases with gap. Incidence angles at the inlets of rotors are less for the smaller gaps. Deviation angle at the outlet of rotor 1 is also considered, as rotor 1-rotor 2 interaction is more significant in CRT. Deviation angle at rotor 1 outlet is minimum for this gap. Also, for the intermediate mass flow rate of 0.108, x/a = 0.3 is giving more stage performance. This suggests that at certain axial gap, there is better wake convection and flow outline, when compared to other gap cases. Further, it is identified that for the axial gap of x/a = 0.3 and the mean mass flow rate of 0.108, the performance of CRT is maximum. It is clear that the flow pattern at the interface is changing the incidence and deviation with change in axial gap and flow rate. This study is useful for the gas turbine community to identify the flow rates and gaps at which any CRT stage would perform better.
Heat Transfer Enhancement in Duct With Rectangular Fin Arrays
Authors: Islam Md. , Barsoum I.
Published: January 2020

The need for efficient cooling techniques has motivated researchers to focus into heat transfer and flow behavior of various configurations of finned surfaces. Inclined rectangular fin is found to be an effective vortex generator for heat transfer augmentation, wherein longitudinal vortices is generated and keeps intensity at far downstream. It is expected that the heat transfer from the endwall and the fin surface can be improved and hence we have identified this configuration as very promising. Rectangular fins of different height were constructed and experimental investigation of heat transfer and flow with arrays of rectangular fins was conducted. Effect of velocity, attack angle, fin height and pitch ratio on local heat transfer coefficients is studied. In order to accomplish the experiment, 7 × 7 arrays of rectangular fins were attached on the heating surface and then placed in rectangular duct with different angle of attack to the free stream flow. Stream wise heat transfer coefficients were measured both at centerline and of 10 mm off line of heating surface by means of the thermocouples. T-type thermocouples and an infrared camera (TVS 8000) with a 160 × 120 point In-Sb sensor were used to measure the temperature and the detailed heat transfer from the endwall along with fin base.
Nonlinear Interactions Within a Flexible Rotating Shaft
Authors: Kartheek Amaroju , Vijayan Kiran
Published: January 2020

Designing of an industrial gas turbine rotor needs a special attention to ensure safe and reliable operation of the entire machine. Rotor experiences bending, axial, and torsional vibration during the time of operation and Rotor-stator interaction during whirling involves nonlinearities in the form of friction and impact. Rub-impact is the most common fault in rotating machinery, which causes excessive vibration and reduces the efficiency of the machine. Therefore, it is very important to study and understand the contact phenomena in rotor dynamics. The purpose of this study is to understand the modal interactions that occur in a rotating flexible member. A conceptual test rig for the rotor-stator is developed experimentally and a corresponding numerical model for the system is developed. The test rig consists of a flexible rotor with two discs rotating within a localised conduit. The system is modelled as a Euler Bernoulli beam with two discs. Finite element method is used to model the system. The gyroscopic effects of the rotor also included in the model. The forward whirling frequency obtained from the experiments was used to update the bearing stiffness of the theoretical model. The contact is modelled experimentally using localised conduit with added roughness to aggravate the friction effect. A run-up analysis was carried out within the safe operating regime of the test rig and the frequencies were analysed using a time-frequency plot. The results from the study indicated the possibility of interaction between the forward and backward whirling modes which results in steady nonlinear backward whirl behaviour.
Atomic layer deposition of nitrogen incorporated molybdenum oxide: Unveiling carrier transport mechanism and its application in Li-ion battery
Authors: Dhara Arpan , Saha Debabrata , Mitra Sagar , Sarkar Shaibal K.
Published: January 2020

Nitrogen incorporated molybdenum oxide (MoOx:N) thin films are obtained by stacking of atomic layer deposited grown MoOx and MoNx in a nanolaminate architecture without any postdeposition processing. Evolution of stoichiometrically dependent electron conductivity is obtained that is efficiently controlled by varying the ratio of the number of layers (MoOx to MoNx) in the nanolaminate structure. The carrier type, the free carrier concentration, and the mobility of the as-grown materials are studied by temperature-dependent Hall-effect measurement. The authors hypothesize that the addition of N-atom creates oxygen vacancies in the films that in turn act as a shallow donor level that results in improved conductivity in the ternary material. As-grown materials, both in the form of planar architecture and coaxially grown on multiwalled carbon nanotubes are investigated as a prospective anode material in the Li-ion battery. The comparison reveals a substantially improved performance of N-incorporated samples than that of the pristine materials. The highest discharge capacity of 1287 mA h g−1 was achieved in the first cycle at a current rate of 0.1 A g−1, and a stable capacity of 974 and 610 mA h g−1 is achieved when discharged at 0.1 and 2 A g−1, respectively, from the core-shell structures.
A uniform explanation of all falling chain phenomena
Authors: Denny Mark
Published: January 2020

The many variants of falling chain problems that have been published in the physics literature over the last two centuries are here analyzed using generalized Euler–Lagrange equations that include momentum flux. Familiar results are recovered, and new ones are presented. We demonstrate and clarify the role played by momentum flux by considering the falling chains as both variable-mass and fixed-mass systems. We calculate the evolution of energy as a useful parameter that provides insight into some of the unexpected behavior of falling chain systems. Our Lagrangian approach incorporates all published falling chain phenomena (including the whiplash effect) within a unifying framework, highlighting connections between the phenomena and providing a valuable pedagogical example of variable mass systems analysis.
A tensile ring drives tissue flows to shape the gastrulating amniote embryo
Authors: Saadaoui Mehdi , Rocancourt Didier , Roussel Julian , Corson Francis , Gros Jerome
Published: January 2020

Shaping the early amniote embryo

Gastrulation is an essential step in development in which the internal tissues of the body are set apart. In birds and mammals, a similar cascade of molecular events is known to specify embryonic territories, but how they are physically remodeled has remained elusive. Working with avian embryos, Saadaoui
et al.
identified a cable that encircles the embryo as the engine of gastrulation and described the collective cell movements as similar to the motion of a fluid. One side of this contractile ring pulls more strongly than the other, entraining the large-scale tissue movements that shape the early body plan. The embryo margin, previously known to function in molecular regulation, thus emerges as a dual mechanical and molecular organizer of development.

Science
, this issue p.
453
Lineage tracing on transcriptional landscapes links state to fate during differentiation
Authors: Weinreb Caleb , Rodriguez-Fraticelli Alejo , Camargo Fernando D. , Klein Allon M.
Published: January 2020

Mapping cell fate during hematopoiesis

Biologists have long attempted to understand how stem and progenitor cells in regenerating and embryonic tissues differentiate into mature cell types. Through the use of recent technical advances to sequence the genes expressed in thousands of individual cells, differentiation mechanisms are being revealed. Weinreb
et al.
extended these methods to track clones of cells (cell families) across time. Their approach reveals differences in cellular gene expression as cells progress through hematopoiesis, which is the process of blood production. Using machine learning, they tested how well gene expression measurements account for the choices that cells make. This work reveals that a considerable gap still exists in understanding differentiation mechanisms, and future methods are needed to fully understand—and ultimately control—cell differentiation.

Science
, this issue p.
eaaw3381
Single-cell transcriptional diversity is a hallmark of developmental potential
Authors: Gulati Gunsagar S. , Sikandar Shaheen S. , Wesche Daniel J. , Manjunath Anoop , Bharadwaj Anjan , Berger Mark J. , Ilagan Francisco , Kuo Angera H. , Hsieh Robert W. , Cai Shang , Zabala Maider , Scheeren Ferenc A. , Lobo Neethan A. , Qian Dalong , Yu Feiqiao B. , Dirbas Frederick M. , Clarke Michael F. , Newman Aaron M.
Published: January 2020

More diversity at the top

A detailed knowledge of cell differentiation hierarchies is important for understanding diverse biological processes such as organ development, tissue regeneration, and cancer. Single-cell RNA sequencing can help elucidate these hierarchies, but it requires reliable computational methods for predicting cell lineage trajectories. Gulati
et al.
developed CytoTRACE, a computational framework based on the simple observation that transcriptional diversity—the number of genes expressed in a cell—decreases during differentiation. CytoTRACE outperformed other methods in several test cases and was successfully applied to study cellular hierarchies in healthy and tumor tissue.

Science
, this issue p.
405
Quantum anomalous Hall effect in intrinsic magnetic topological insulator MnBi
2
Te
4
Authors: Deng Yujun , Yu Yijun , Shi Meng Zhu , Guo Zhongxun , Xu Zihan , Wang Jing , Chen Xian Hui , Zhang Yuanbo
Published: January 2020

Quantum anomalous Hall goes intrinsic

Quantum anomalous Hall effect—the appearance of quantized Hall conductance at zero magnetic field—has been observed in thin films of the topological insulator Bi
2
Se
3
doped with magnetic atoms. The doping, however, introduces inhomogeneity, reducing the temperature at which the effect occurs. Two groups have now observed quantum anomalous Hall effect in intrinsically magnetic materials (see the Perspective by Wakefield and Checkelsky). Serlin
et al.
did so in twisted bilayer graphene aligned to hexagonal boron nitride, where the effect enabled the switching of magnetization with tiny currents. In a complementary work, Deng
et al.
observed quantum anomalous Hall effect in the antiferromagnetic layered topological insulator MnBi
2
Te
4
.

Science
, this issue p.
900
, p.
895
; see also p.
848
Designing for a green chemistry future
Authors: Zimmerman Julie B. , Anastas Paul T. , Erythropel Hanno C. , Leitner Walter
Published: January 2020

The material basis of a sustainable society will depend on chemical products and processes that are designed following principles that make them conducive to life. Important inherent properties of molecules need to be considered from the earliest stage—the design stage—to address whether compounds and processes are depleting versus renewable, toxic versus benign, and persistent versus readily degradable. Products, feedstocks, and manufacturing processes will need to integrate the principles of green chemistry and green engineering under an expanded definition of performance that includes sustainability considerations. This transformation will require the best of the traditions of science and innovation coupled with new emerging systems thinking and systems design that begins at the molecular level and results in a positive impact on the global scale.
Four glial cells regulate ER stress resistance and longevity via neuropeptide signaling in
C. elegans
Authors: Frakes Ashley E. , Metcalf Melissa G. , Tronnes Sarah U. , Bar-Ziv Raz , Durieux Jenni , Gildea Holly K. , Kandahari Nazineen , Monshietehadi Samira , Dillin Andrew
Published: January 2020

Taking the stress out of life

In the model organism
Caenorhabditis elegans
, a roundworm, it has been shown that neurons can communicate proteostasis to the periphery to affect aging. Frakes
et al.
have now identified astrocytelike glial cells that also act as central regulators of systemic protein homeostasis and aging (see the Perspective by Miklas and Brunet). They found that the life span of
C. elegans
can be extended by expression of a constitutively active version of the transcription factor XBP-1s, which mediates the unfolded protein response of the endoplasmic reticulum (UPR
ER
), in a specific subset of glial cells. Glial XBP-1s initiates induction of the UPR
ER
in distal intestinal cells, which makes the worms more resistant to chronic ER stress. Neuropeptide signaling was required for glial-mediated longevity and induction of the peripheral UPR
ER
, suggesting a distinct mechanism from that initiated by neuronal XBP-1s. Thus, in this animal model of aging, a mere four cells can control organismal physiology and aging

Science
, this issue p.
436
; see also p.
365
Entanglement-based single-shot detection of a single magnon with a superconducting qubit
Authors: Lachance-Quirion Dany , Wolski Samuel Piotr , Tabuchi Yutaka , Kono Shingo , Usami Koji , Nakamura Yasunobu
Published: January 2020

Detecting a single magnetic excitation

Quantum-enhanced sensing is one of the near-term applications for the developing field of quantum technologies. A promising approach to quantum sensing relies on entangling a well-controlled system (the sensor) to the system of interest to detect quanta of excitations in the latter. By entangling a superconducting qubit with a ferrimagnetic crystal, Lachance-Quirion
et al.
demonstrate that they can detect a quantum of magnetic excitation (a magnon) within the sample. The demonstration of a high-efficiency single-magnon detector will be useful for quantum sensing as well as an active component of hybrid quantum systems and should find a wide range of applications in quantum technologies.

Science
, this issue p.
425
Nutrient Level Determines Biofilm Characteristics and Subsequent Impact on Microbial Corrosion and Biocide Effectiveness
Authors: Salgar-Chaparro Silvia J. , Lepkova Katerina , Pojtanabuntoeng Thunyaluk , Darwin Adam , Machuca Laura L.
Published: January 2020

Microbiologically influenced corrosion (MIC) is a complex process that generates economic losses to the industry every year. Corrosion must be managed to prevent a loss of containment of produced fluids to the external environment. MIC management includes the identification of assets with higher MIC risk, which could be influenced by nutrient levels in the system. Assessing biofilms under different nutrient conditions is essential for understanding the impact of flow regime on microbial communities and the subsequent impact on microbial corrosion and on the effectiveness of biocide treatment. This investigation simulates closely oil production systems, which contain piping sections exposed to continuous flow and sections that remain stagnant for long periods. Therefore, the results reported here are useful for MIC management and prevention. Moreover, the complementary methodological approach applied in this investigation highlighted the importance of implementing RNA-based methods for better identification of active microorganisms that survive stress conditions in oil systems.
Evaluation of the NG-Test MCR-1 Lateral Flow Assay and EDTA-Colistin Broth Disk Elution Methods To Detect Plasmid-Mediated Colistin Resistance among Gram-Negative Bacterial Isolates
Authors: Fenwick Alexander J. , Bergman Yehudit , Lewis Shawna , Yee Rebecca , Uhlemann Anne-Catrin , Cole Nicolynn , Kohner Peggy , Ordak Carly , Green Daniel A. , Schuetz Audrey N. , Humphries Romney , Simner Patricia J.
Published: January 2020

Plasmid-mediated colistin resistance (PMCR) is a global public health concern, given its ease of transmissibility. The purpose of this study was to evaluate two methods for the detection of PMCR from bacterial colonies: (i) the NG-Test MCR-1 lateral flow immunoassay (LFA; NG Biotech, Guipry, France) and (ii) the EDTA-colistin broth disk elution (EDTA-CBDE) screening test method. These methods were evaluated using a cohort of contemporary, clinical Gram-negative bacillus isolates from 3 U.S. academic medical centers (126 isolates of the
Enterobacterales
, 50
Pseudomonas aeruginosa
isolates, and 50
Acinetobacter
species isolates; 1 isolate was
mcr
positive) and 12
mcr
-positive CDC-FDA Antibiotic Resistance (AR) Isolate Bank isolates for which reference broth microdilution colistin susceptibility results were available.
Outcomes of phacoemulsification combined with two iStent inject trabecular microbypass stents with or without endocyclophotocoagulation
Authors: Pantalon Anca Delia , Barata Andre Diogo De Oliveira , Georgopoulos Minas , Ratnarajan Gokulan
Published: January 2020

Aim

Comparing outcomes after combined phacoemulsification, two iStents insertion and endocyclophotocoagulation (ECP) versus phacoemulsification-iStents alone.

Methods

This is a longitudinal retrospective 12 months study in eyes with ocular hypertension or early-to-moderate open angle glaucoma. Level of disease, intraocular pressure (IOP) and tolerance of glaucoma medication were considered before planning surgery. Best-corrected visual acuity (BCVA-logMAR), IOP (mm Hg), number of medications were assessed at baseline, week 1, week 5, month 3, 6, 12 postop. Main outcome: percentage (%) in IOP reduction at 12 months vs medicated baseline. Secondary outcomes: absolute values of IOP/medication reduction, BCVA and postop complications.

Results

The ICE2 (two iStents-cataract extraction-ECP) group included 63 eyes and Phaco-iStent group included 46 eyes. Baseline IOP was higher in the ICE2 than phaco-iStent group (19.97±4.31 mm Hg vs 17.63±3.86 mm Hg, p=0.004) and mean deviation was lower (−7.20±2.58 dB vs −4.94±4.51 dB, p=0.037). Number of medications were comparable at baseline: 2.22±1.06 (ICE2) vs 2.07±1.02 (phaco-iStent), p=0.442. At month 12 postop, IOP in the ICE2 group decreased 35% from baseline vs 21% in the phaco-iStent group (p=0.03); absolute IOP reduction was significantly lower than baseline in each group (p<0.001), yet final IOP was lower in the ICE2 group than phaco-iStent group (13.05±2.18 mm Hg vs 14.09±1.86 mm Hg, p=0.01). Similar results were found for glaucoma medication (1.24±1.05 in ICE2 group vs 1.39±1.03 in phaco-iStent group, p=0.01). Final BCVA was 0.11±0.18 (phaco-iStent group) vs 0.08±0.08 (ICE2 group), p=0.309. Safety outcomes were comparable between groups.

Conclusion

ICE2 procedure offers better results in IOP/medication reduction at 12 months than phacoemulsification-iStents alone.
Association of serum magnesium level change with in-hospital mortality
Authors: Thongprayoon Charat , Cheungpasitporn Wisit , Hansrivijit Panupong , Thirunavukkarasu Sorkko , Chewcharat Api , Medaura Juan , Mao Michael A , Kashani Kianoush B
Published: January 2020

The objective of this study was to assess the association of in-hospital mortality risk based on change in serum magnesium levels in hospitalised patients. All adult patients admitted to our hospital from years 2009 to 2013 with at least two serum magnesium measurements during hospitalisation were included. Serum magnesium change, defined as the absolute difference between the highest and lowest serum magnesium, was categorised into six groups: 0–0.2, 0.3–0.4, 0.5–0.6, 0.7–0.8, 0.9–1.0, ≥1.1 mg/dL. In-hospital mortality was the outcome of interest. Logistic regression was used to assess the association between serum magnesium change and in-hospital mortality, using serum magnesium change of 0.0–0.2 mg/dL as the reference group. A total of 42 141 patients, with the median serum magnesium change during hospital stay of 0.3 (IQR 0.2–0.6) mg/dL, were studied. In-hospital mortality based on serum magnesium change of 0–0.2, 0.3–0.4, 0.5–0.6, 0.7–0.8, 0.9–1.0, ≥1.1 mg/dL was 1.3%, 2.3%, 3.1%, 5.0%, 6.5%, and 8.8%, respectively (p<0.001). After adjustment for potential confounders, increased serum magnesium change was significantly associated with higher in-hospital mortality with adjusted OR of 1.39 (95% 1.14–1.69) in serum magnesium change of 0.3–0.4, 1.48 (95% CI 1.21 to 1.81) in 0.5–0.6, 1.89 (95% CI 1.53 to 2.34) in 0.7–0.8, 1.85 (95% CI 1.45 to 2.37) in 0.9–1.0 and 1.89 (95% CI 1.48 to 2.41) in ≥1.1 mg/dL when compared with serum magnesium change group of 0–0.2 mg/dL. Increased in-hospital mortality was associated with both downward and upward trends of serum magnesium change during hospitalisation. The greater extent of change in serum magnesium levels was progressively associated with increased in-hospital mortality
Workforce predictive risk modelling: development of a model to identify general practices at risk of a supply−demand imbalance
Authors: Abel Gary A , Gomez-Cano Mayam , Mustafee Navonil , Smart Andi , Fletcher Emily , Salisbury Chris , Chilvers Rupa , Dean Sarah Gerard , Richards Suzanne H , Warren F , Campbell John L
Published: January 2020

Objective

This study aimed to develop a risk prediction model identifying general practices at risk of workforce supply–demand imbalance.

Design

This is a secondary analysis of routine data on general practice workforce, patient experience and registered populations (2012 to 2016), combined with a census of general practitioners’ (GPs’) career intentions (2016).

Setting/Participants

A hybrid approach was used to develop a model to predict workforce supply–demand imbalance based on practice factors using historical data (2012–2016) on all general practices in England (with over 1000 registered patients n=6398). The model was applied to current data (2016) to explore future risk for practices in South West England (n=368).

Primary outcome measure

The primary outcome was a practice being in a state of workforce supply–demand imbalance operationally defined as being in the lowest third nationally of access scores according to the General Practice Patient Survey and the highest third nationally according to list size per full-time equivalent GP (weighted to the demographic distribution of registered patients and adjusted for deprivation).

Results

Based on historical data, the predictive model had fair to good discriminatory ability to predict which practices faced supply–demand imbalance (area under receiver operating characteristic curve=0.755). Predictions using current data suggested that, on average, practices at highest risk of future supply–demand imbalance are currently characterised by having larger patient lists, employing more nurses, serving more deprived and younger populations, and having considerably worse patient experience ratings when compared with other practices. Incorporating findings from a survey of GP’s career intentions made little difference to predictions of future supply–demand risk status when compared with expected future workforce projections based only on routinely available data on GPs’ gender and age.

Conclusions

It is possible to make reasonable predictions of an individual general practice’s future risk of undersupply of GP workforce with respect to its patient population. However, the predictions are inherently limited by the data available.
Adolescent undernutrition in South Asia: a scoping review protocol
Authors: Estecha Querol Sara , Al-Khudairy Lena , Iqbal Romaina , Johnson Samantha , Gill Paramjit
Published: January 2020

Introduction

The aim of the protocol is to present the methodology of a scoping review that aims to synthesise up-to-date evidence on adolescent undernutrition in South Asia.

Methods and analysis

The proposed scoping review will be guided by Arksey and O’Malley’s framework and the Joanna Briggs Institute Reviewers’ Manual. The scoping review question, eligibility criteria and search strategy will be based on the Population, Concept and Context strategy. We will conduct the search in electronic bibliographic databases (Medline (OVID), Embase, Cochrane Library, Web of Science, CINAHL, PsycInfo, Scopus) as well as various grey literature sources in order to synthesise and present the findings with descriptive statistics and a narrative description of both quantitative and qualitative evidence.

Ethics and dissemination

This study protocol does not require ethical approval. This protocol will accurately describe the proposed scoping review that will map the evidence on adolescent undernutrition in South Asia. The proposed review aims to gather published and unpublished literature to inform policy and healthcare organisations as well as identify future research priorities in South Asia.
The outcomes of biliary drainage by percutaneous transhepatic cholangiography for the palliation of malignant biliary obstruction in England between 2001 and 2014: a retrospective cohort study
Authors: Rees James , Mytton Jemma , Evison Felicity , Mangat Kamarjit Singh , Patel Prashant , Trudgill Nigel
Published: January 2020

Introduction

Relieving obstructive jaundice in inoperable pancreato-biliary cancers improves quality of life and permits chemotherapy. Percutaneous transhepatic cholangiography with drainage and/or stenting relieves jaundice but can be associated with significant morbidity and mortality. Percutaneous transhepatic biliary drainage (PTBD) in malignant biliary obstruction was therefore examined in a national cohort to establish risk factors for poor outcomes.

Methods

Retrospective study of adult patients undergoing PTBD for palliation of pancreato-biliary cancer in England between 2001 and 2014 identified from Hospital Episode Statistics. Multivariate logistic regression analysis was used to examine associations with mortality and the need for a repeat PTBD within 2 months.

Results

16 822 patients analysed (median age 72 (range 19–104) years, 50.3% men). 58% pancreatic and 30% biliary tract cancer. In-hospital and 30-day mortality were 15.3% (95% CI 14.7% to 15.9%) and 23.1% (22.4%–23.8%), respectively. 20.2% suffered a coded complication within 3 months. Factors associated with 30-day mortality: age (≥81 years OR 2.68 (95% CI 2.37 to 3.03), p<0.001), increasing comorbidity (Charlson score 20+, 3.10 (2.64–3.65), p<0.001), pre-existing renal dysfunction (2.37 (2.12–2.65), p<0.001) and non-pancreatic cancer (unspecified biliary tract 1.28 (1.08–1.52), p=0.004). Women had lower mortality (0.91 (0.84–0.98), p=0.011), as did patients undergoing PTBD in a ‘higher volume’ provider (84–180 PTBDs per year 0.68 (0.58–0.79), p<0.001).

Conclusions

In patients undergoing PTBD for the palliation of malignant biliary obstruction, 30-day mortality was high at 23.1%. Mortality was higher in older patients, men, those with increasing comorbidity, a cancer site other than pancreas and at ‘lower-volume’ PTBD providers.
Association of sedentary behaviour patterns with dietary and lifestyle habits among public school teachers: a cross-sectional study
Authors: Delfino Leandro Dragueta , Tebar William Rodrigues , Gil Fernanda Caroline , De Souza Jefferson Marinho , Romanzini Marcelo , Fernandes Romulo Araujo , Christofaro Diego Giulliano Destro
Published: January 2020

Objectives

To analyse the association of sedentary behaviour patterns with dietary and lifestyle habits among public school teachers.

Design

Cross-sectional study.

Participants

A sample of 245 teachers (186 women and 59 men) with mean age of 45.2 (±10.4) were randomly selected from public schools.

Primary and secondary outcome measure

Sedentary behaviour was assessed by hours spent watching television, computer and cellphone/tablet use and in sitting position. Sedentary breaks were reported in a Likert scale in domains of work and leisure time. Dietary habits were assessed by weekly consumption of fruits, vegetables, dairy products, fried foods, sweets, grains, cereals, white meat, soft drinks and snacks. Physical activity, smoking, alcohol consumption and socioeconomic status were assessed by using questionnaires.

Results

The prevalence of high sedentary behaviour, high sedentary breaks at work and at leisure was 57.9%, 67.7% and 70.2% in the sample, respectively. No relationship was observed of high sedentary behaviour with dietary and lifestyle habits in adjusted analysis. However, high sedentary breaks at work were associated with high consumption of dairy products (OR=1.93 (CI 1.07 to 3.51)) and cereals (OR=2.49 (CI 1.05 to 5.92)) and with being high physically active (OR=2.57 (CI 1.14 to 5.77)). High sedentary breaks at leisure time were associated with high consumption of fruits (OR=2.33 (CI 1.28 to 4.23)) and vegetables (OR=1.91 (CI 1.05 to 3.49)) and with be high physically active (OR=2.34 (CI 1.03 to 5.35)). High sedentary breaks were associated with better dietary habits even among teachers with high sedentary behaviour.

Conclusion

High sedentary breaks were associated with better dietary habits and with high levels of physical activity among public school teachers, even those with high sedentary behaviour.