bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of lower nighttime diastolic blood pressure and hypoxia with silent myocardial injury: The Japan Morning Surge‐Home Blood Pressure study
Authors: Kubota Kana , Hoshide Satoshi , Kario Kazuomi
Published: December 2020

Whether marked nocturnal blood pressure (BP) reduction is associated with cardiovascular disease (CVD) is still controversial. In addition, no report has yet discussed the relationship between lower nocturnal BP and CVD, involving modification by nighttime hypoxia. We evaluated 840 patients who had one or more cardiovascular risk factors by measuring their high‐sensitivity cardiac troponin T (Hs‐cTnT), N‐terminal pro‐B‐type natriuretic peptide (NT‐pro BNP), and nighttime saturation levels and performing ambulatory BP monitoring. The lowest tertile in nighttime diastolic BP (DBP) (≤66 mmHg) had increased likelihood of the presence of ≥0.014 ng/ml of Hs‐cTnT compared with the second tertile (odds ratio [OR] 1.91, 95% confidence interval [CI] 1.01–3.63), and the lowest tertile of minimum blood oxygen saturation (≤81%) had increased likelihood of the presence of ≥0.014 ng/ml of Hs‐cTnT compared with the third tertile (OR 2.15, 95% CI 1.13–4.10). Additionally, the patients with both lowest tertile of nighttime DBP and minimum SpO2 showed increased likelihood of the presence of ≥0.014 ng/ml of Hs‐cTnT compared with those without this combination (OR 2.93, 95% CI 1.40–6.16). On the other hand, these associations were not found in the presence of ≥125 pg/ml of NT‐pro BNP. In the clinical population, each of lower nocturnal DBP and nighttime hypoxia was associated with asymptomatic myocardial injury, which was represented as higher Hs‐cTnT, and coexisting lower nocturnal DBP and nighttime hypoxia had an additive effect on the risk of myocardial injury.
Consequences of population structure for sex allocation and sexual conflict
Authors: R. Rodrigues Leonor , Torralba Sáez Mario , Alpedrinha João , Lefèvre Sophie , Brengues Muriel , Magalhães Sara , Duncan Alison B.
Published: December 2020

Both sex allocation and sexual conflict can be modulated by spatial structure. However, how the interplay between the type of dispersal and the scale of competition simultaneously affects these traits in sub‐divided populations is rarely considered. We investigated sex allocation and sexual conflict evolution in meta‐populations of the spider mite Tetranychus urticae evolving under budding (pairing females from the same patch) or random (pairing females from different patches) dispersal and either local (fixed sampling from each subpopulation) or global (sampling as a function of subpopulation productivity) competition. Females evolving under budding dispersal produced less female‐biased offspring sex ratios than those from the random dispersal selection regimes, contradicting theoretical predictions. In contrast, the scale of competition did not strongly affect sex allocation. Offspring sex ratio and female fecundity were unaffected by the number of mates, but female fecundity was highest when their mates evolved under budding dispersal, suggesting these males inflict less harm than those evolving under random dispersal. This work highlights that population structure can impact the evolution of sex allocation and sexual conflict. Moreover, selection on either trait may reciprocally affect the evolution of the other, for example via effects on fecundity.
Women's Experience of Pelvic Girdle Pain After Childbirth: A Meta‐Synthesis
Authors: Srisopa Pornpan , Lucas Ruth
Published: December 2020

Introduction

Persistent pelvic girdle pain (PGP) and the resulting consequences may occur for more than 10 years after birth. The purpose of this meta‐synthesis is to provide a new interpretation and deeper understanding of women's experience of living with PGP postpartum.

Methods

A literature review of CINAHL, PsycINFO, PubMed, Scopus, and ProQuest dissertations was conducted for any qualitative study addressing PGP after birth and published in English from 2000 to 2019. A meta‐synthesis using Noblit and Hare's meta‐ethnography approach was performed.

Results

Seven studies were found describing the experiences of women living with PGP from birth to 13 years after birth. Six themes emerged that represented women's experience: invisible pain, life being restrained, failure to perform the maternal role, experiencing downward emotional spiral, need for active social support, and adaptation to a new conditional life.

Discussion

The experiences of women living with PGP after birth highlight the need for holistic care. Interventions by health care providers should support the ability of women to perform daily functions and adapt to their new reality instead of a disease‐focused intervention. In addition, women with PGP emphasize the importance of active social support from family members and health care providers. Future research that examines the differences between PGP during the first 3 months postpartum versus that which persists later is needed to develop targeted interventions.
Assessment of Bolbophorus damnificus prevalence and cercariae shedding in Planorbella trivolvis populations from catfish aquaculture ponds in Mississippi, USA
Authors: Gunn Mackenzie A. , Allen Peter J. , Rosser Thomas Graham , Wise David J. , Khoo Lester H. , Griffin Matt J.
Published: December 2020

Bolbophorus damnificus (Digenea: Bolbophoridae) causes significant losses in US catfish aquaculture. Little is known regarding the prevalence of infected snail hosts during outbreaks. To assess prevalence of snails observed shedding Bolbophorus spp. cercariae, as well as snails that were infected but not observed shedding cercariae, Planorbella trivolvis (n = 8,159) were collected from 14 catfish production ponds with B. damnificus activity in Mississippi, USA. Individual snails were placed in 10 ml of filtered (20 μm) reservoir pond water and observed for 48 hr for cercariae release. Identification of B. damnificus or Bolbophorus sp. type II cercariae was confirmed by duplex PCR. Genomic DNA was isolated from ~100 non‐shedding snails from each pond and the PCR assay used to identify the presence of B. damnificus or Bolbophorus sp. type II infected snails. The prevalence of snails shedding B. damnificus ranged from 0.23 to 13.6%. Observation of cercariae shedding underestimated true B. damnificus and Bolbophorus sp. type II prevalence in 42.9 and 64.3% of sampled ponds, respectively. Prevalence of B. damnificus infected snails was typically <3%, indicating numbers of infected snails during outbreaks are low and mitigation efforts may be successful simply by reducing snail numbers and not require complete eradication.
Identification of the novel HLA‐DRB1*04:305 allele in a Chinese leukemia patient
Authors: Zhang Jingjing , Fu Rui , Wang Wei , Zhang Wei , Zhu Faming
Published: December 2020

HLA‐DRB1*04:305 differs from HLA‐DRB1*04:05:01:01 by two nucleotide substitutions.
MdABI5 works with its interaction partners to regulate abscisic acid‐mediated leaf senescence in apple
Authors: An Jian‐Ping , Zhang Xiao‐Wei , Liu Ya‐Jing , Zhang Jiu‐Cheng , Wang Xiao‐Fei , You Chun‐Xiang , Hao Yu‐Jin
Published: December 2020

Abscisic acid (ABA) induces chlorophyll degradation and leaf senescence; however, the molecular mechanism remains poorly understood, especially in woody plants. In this study, we found that MdABI5 plays an essential role in the regulation of ABA‐triggered leaf senescence in Malus domestica (apple). Through yeast screening, three transcription factors, MdBBX22, MdWRKY40 and MdbZIP44, were found to interact directly with MdABI5 in vitro and in vivo. Physiological and biochemical assays showed that MdBBX22 delayed leaf senescence in two pathways. First, MdBBX22 interacted with MdABI5 to inhibit the transcriptional activity of MdABI5 on the chlorophyll catabolic genes MdNYE1 and MdNYC1, thus negatively regulating chlorophyll degradation and leaf senescence. Second, MdBBX22 interacted with MdHY5 to interfere with the transcriptional activation of MdHY5 on MdABI5, thereby inhibiting the expression of MdABI5, which also contributed to the delay of leaf senescence. MdWRKY40 and MdbZIP44 were identified as positive regulators of leaf senescence. They accelerated MdABI5‐promoted leaf senescence through the same regulatory pathways, i.e., interacting with MdABI5 to enhance the transcriptional activity of MdABI5 on MdNYE1 and MdNYC1. Taken together, our results suggest that MdABI5 works with its positive or negative interaction partners to regulate ABA‐mediated leaf senescence in apple, in which it acts as a core regulator. The antagonistic regulation pathways ensure that plants respond to external stresses flexibly and efficiently. Our results provide a concept for further study on the regulation mechanisms of leaf senescence.
Contribution of donor‐ and recipient‐associated factors to allergic transfusion reactions to platelets
Authors: Zheng Yan , Pei Deqing , Sweat Lori , Ryan Missy , Mestemacher Mark A. , Gann Maria , Cheng Cheng , Geiger Terrence L.
Published: December 2020

Background

Pediatric hematology‐oncology patients require frequent platelet transfusions to manage chemotherapy‐induced thrombocytopenia, and allergic transfusion reactions (ATRs) are common. Risk for platelet‐associated ATRs can result from recipient‐ or donor‐specific factors.

Study Design and Methods

We report a rare case in which an individual platelet donor caused repeated ATRs in multiple recipients. This observation led us to conduct a retrospective study at a pediatric hematology‐oncology center to identify donor‐ and recipient‐associated risk factors for ATRs.

Results

Single‐donor platelets from an individual donor precipitated ATRs in 78.6% (n = 11/14) of recipients and 66.7% (n = 12/18) of platelet transfusions. We found in a cohort of pediatric hematology‐oncology patients that 12.6% of recipients and 1.0% of platelet transfusions were associated with ATRs. Recipients who were aged 4 to 18 years, male, and those with central nervous system or solid tumors and with a history of ATRs to platelets were more likely to experience ATRs. Donor‐associated risk factors were not identified, and we did not implicate additional donors in our single‐center cohort with a frequency of ATRs comparable to the index donor. Based on our findings, we developed a novel statistical model to identify recipients and donors prone to experiencing or mediating ATRs.

Conclusions

Both donors and recipients contribute to ATRs. Identification of high‐risk donors and recipients for further scrutiny and potential interventions can improve the safety of platelet transfusions.
Inflation targeting adoption and institutional quality: Evidence from developing countries
Authors: Minea Alexandru , Tapsoba René , Villieu Patrick
Published: December 2020

Institutional quality is often emphasised as an engine of economic development in developing countries. However, most of the literature assumes that institutions are exogenous. In this paper, we adopt the opposite view, and study the way the design of the monetary regime, and specifically the adoption of an inflation targeting regime, can impact the quality of institutions. Using the propensity scores matching method, which allows controlling for self‐selection in policy adoption, along with a wide set of robustness checks, including GMM‐based estimations and controlling for unobserved heterogeneity, we find that the adoption of inflation targeting significantly improves the quality of institutions.
Proof of Concept for a Novel Interstage Injection Design in Axial Compressors
Authors: Doerr T. , Braun S. , Schuster S. , Brillert D.
Published: December 2020

A common technique to increase the thermal efficiency and the power output of gas turbines is to inject water upstream of the compressor section. Through the evaporation of the water throughout the compressor, an isothermal process is approached. A recently developed technology for this enhanced process is interstage injection in which water is injected directly between the stages. One advantage of this over wet compression is the avoidance of icing, since the local temperatures at the injection positions are already above melting point. Moreover, stage characteristics and load distribution can be rearranged within the compressor by individually adjusting the injection amount in different stages. However, there is little practical understanding of this process, and suitable injection methods have still to be found. This paper therefore demonstrates the implementation of a novel technology of interstage injection in an axial compressor test rig whereby twin jet nozzles are integrated directly into the trailing edge of the first stator row to deliver a homogenous spray over the entire radial span. Due to the resultant blade complexity, blades are manufactured by selective laser melting (SLM) and subsequently installed in an enhanced four-stage axial compressor. The installed control and measurement principles of the test rig are presented and results demonstrate the functionality of the innovative design.
Mechanics of Microspheres Reinforced Hollow Microcells
Authors: Youssef George , Nacy Somer , Huynh Nha Uyen
Published: December 2020

Emerging polymeric foams exhibiting unique microstructure of microspherical shells with reinforcing dense microspheres creates a new opportunity for impact-tolerant foam paddings in sport gears applications. This paper describes the static response of reinforced microcell consisting of an outer spherical shell and uniformly distributed microspheres while quantifying the stiffening effect. The distribution of the microspheres is illustrated using the Fourier series, allowing tuning of the reinforcing strategy. Expressions of the external and internal works are derived, whereas the Ritz energy method is adopted to calculate the deformations due to a compressive load distributed over a range of areas. Emphasis is given to the effect of the geometrical attributes of the microcell and the reinforcing microspheres on the resulting deformation response and stiffening effect. The framework is used to investigate the response of several case studies to elucidate the effects of relative radii ratio, reinforcement density, microcell wall thickness, and loading configurations on the stiffness. A new normalized strain energy parameter is introduced to simplify and accelerate the analysis while providing insights on the underpinnings of the observed buckling response. The results strongly suggest the viability of the newly discovered foam microstructure in managing static loads while providing an opportunity to strategically tune the mechanical response using the analytical framework presented herein.
Large Deformation and Instability of Soft Hollow Cylinder With Surface Effects
Authors: Wang Qitao , Liu Mingchao , Wang Zhenyu , Chen Changqing , Wu Jian
Published: December 2020

Surface stress, which is always neglected in classical elastic theories, has recently emerged as a key role in the mechanics of highly deformable soft solids. In this paper, the effect of surface stress on the deformation and instability of soft hollow cylinder is analyzed. By incorporating surface energy density function into the constitutive model of a hyper-elastic theory, explicit solutions are obtained for the large deformation of soft hollow cylinder under the uniform pressure loading and geometric everting. The surface tension and the residual surface stress have a significant effect on the large deformation and instability of the soft cylinder. When the pressure loading and geometric everting are applied on the soft hollow cylinder, significant changes in the critical condition of the creases are found by varying the surface parameters. Two models of instability, surface crease and global buckling behavior, will be generated on the soft hollow cylinder with the uniform pressure, and the formed instability model is dependent on the ratio of the thickness to the radius. The results in this work reveal that surface energy obviously influences both the deformation and the instability of soft hollow cylinder at finite deformation and will be helpful for understanding and predicting the mechanical behavior of soft structures accurately.
Magnetic Forces Enable Control of Biological Processes In Vivo
Authors: Bao Gang
Published: December 2020

Similar to mechanical forces that can induce profound biological effects, magnetic fields can have a broad range of implications to biological systems, from magnetoreception that allows an organism to detect a magnetic field to perceive direction, altitude, or location, to the use of heating induced by magnetic field for altering neuron activity. This review focuses on the application of magnetic forces generated by magnetic iron oxide nanoparticles (MIONs), which can also provide imaging contrast and mechanical/thermal energy in response to an external magnetic field, a special feature that distinguishes MIONs from other nanomaterials. The magnetic properties of MIONs offer unique opportunities for enabling control of biological processes under different magnetic fields. Here, we describe the approaches of utilizing the forces generated by MIONs under an applied magnetic field to control biological processes and functions, including the targeting of drug molecules to a specific tissue, increasing the vessel permeability for improving drug delivery, and activating a particular viral vector for spatial control of genome editing in vivo. The opportunities of using nanomagnets for a broad range of biomedical applications are briefly discussed.
The Influence of Cycle-to-Cycle Hydrocarbon Emissions on Cyclic NO:NO2 Ratio From a HSDI Diesel Engine
Authors: Leach Felix , Shankar Varun , Davy Martin , Peckham Mark
Published: December 2020

Knowledge of the NO:NO2 ratio emitted from a diesel engine is particularly important for ensuring the highest performance of SCR NOx aftertreatment systems. As real driving emissions from vehicles increase in importance, the need to understand the NO:NO2 ratio emitted from a diesel engine during transient operation similarly increases.

Previous work by the authors identified significant differences in NO:NO2 ratio throughout the exhaust period of a single engine cycle, with proportionally more NO2 being emitted during the blowdown period compared to the rest of the exhaust stroke. At the time it was not known what caused this effect.

In this study, crank-angle resolved NO and NO2 measurements using fast response CLD (for NO) and a new fast LIF instrument (for NO2) have been taken from a single cylinder high-speed light duty diesel engine at three different speed and load points including a point with and without EGR. In addition, crank-angle resolved unburned hydrocarbon (UHC) measurements have been taken simultaneously using a fast FID.

The NOx emitted per cycle and the peak cylinder pressure of that cycle have showed high correlation coefficients (R2 < 0.97 at all test points) in this work. In addition, a variation of the NO:NO2 ratio through the engine’s exhaust stroke is also observed indicative of in-cylinder stratification of NO and NO2. A new link between the NO:NO2 ratio and the UHC emissions from an individual engine cycle is observed — the results show that where there are higher levels of UHC emissions in the first part of the exhaust stroke (blowdown), perhaps caused by injector dribble or release from crevices, the proportion of NO2 emitted from that cycle is increased. This effect is observed and analysed across all test points and with and without EGR.

The performance of the new fast LIF analyser has also been evaluated, in comparison with the previous state-of-the-art and standard “slow” emissions measurement apparatus showing a reduction in the noise of the measurement by an order of magnitude.
Simultaneous High-Speed Formaldehyde PLIF and Schlieren Imaging of Multiple Injections From an ECN Spray D Injector
Authors: Maes Noud , Sim Hyung Sub , Weiss Lukas , Pickett Lyle
Published: December 2020

The interaction of multiple injections in a diesel engine facilitates a complex interplay between freshly introduced fuel, previous combustion products, and overall combustion. To improve understanding of the relevant processes, high-speed Planar Laser-Induced Fluorescence (PLIF) with 355-nm excitation of formaldehyde and Polycyclic Aromatic Hydrocarbon (PAH) soot precursors is applied to multiple injections of n-dodecane from Engine Combustion Network Spray D, characterized by a converging 189-μm nozzle. High-speed schlieren imaging is applied simultaneously with 50-kHz PLIF excitation to visualize the spray structures, jet penetration, and ignition processes. For the first injection, formaldehyde (as an indicator of low-temperature chemistry) is first found in the jet periphery, after which it quickly propagates through the center of the jet, towards the jet head prior to high-temperature ignition. At second-stage ignition, downstream formaldehyde is consumed rapidly and upstream formaldehyde develops into a quasi-steady structure for as long as the momentum flux from the injector continues. Since the first injection in this work is relatively short, differences to a single long injection are readily observed, ultimately resulting in high-temperature combustion and PAH structures appearing farther upstream after the end of injection. For the second injection in this work, the first formaldehyde signal is significantly advanced because of the entrained high-temperature combustion products, and an obvious premixed burn event does not occur. The propensity for combustion recession after the end of the first injection changes significantly with ambient temperature, thereby affecting the level of interaction between the first- and second injection.
Dynamic Mode Decomposition for Extracting Cycle-to-Cycle Variation of SIDI Engine In-Cylinder Flow Under Motoring Condition
Authors: Liu Mengqi , Zhao Fengnian , Li Xuesong , Xu Min , Hung David L. S.
Published: December 2020

Cycle-to-cycle variation (CCV) of in-cylinder flow strongly affects the performance and efficiency of spark ignition direct injection (SIDI) engines. In order to achieve a precise flow control inside the engine, the underlying dynamic features of flow field CCV must be thoroughly investigated. In this work, large-eddy simulations (LES) with 50 consecutive cycles are employed for high fidelity numerical realizations of engine flow under motoring condition. To supplement the numerical analysis, time-resolved particle image velocimetry (PIV) measurements are also conducted in several cutting planes. Although the velocity root mean square (RMS) is calculated to quantify the cyclic variation intensity of simulation and experiment results, some important dynamic characteristics cannot be observed directly from velocity data. Therefore, dynamic mode decompositions (DMD), which is a widely used modal decomposition algorithm on fluid study, is used to decompose flow fields into modes with specific frequencies and provide growth rates of corresponding flow structures. This spectral information of in-cylinder flow field is ponderable for uncovering dynamic features of engine CCV. In this study, DMD algorithm is applied on both LES and PIV datasets. The frequency and growth rate differences are employed to elucidate the CCV feature deviations captured by LES and PIV. This research provides a guideline for extracting engine flow field cyclic variability feature using DMD algorithm. Based on the discussion for spectral features and potential sources of flow field variation, the capability of LES to capture CCV features is evaluated. The DMD spectrum differences between PIV and LES can guide the boundary condition perturbations used for simulation fidelity improvements.
A Transported Livengood-Wu Integral Model for Knock Prediction in CFD Simulation
Authors: Yue Zongyu , Xu Chao , Som Sibendu , Sluder C. Scott , Edwards K. Dean , Whitesides Russell , Mcnenly Matthew J.
Published: December 2020

This work describes the development of a transported Livengood-Wu (L-W) integral model for computational fluid dynamics (CFD) simulation to predict auto-ignition and engine knock tendency. The currently employed L-W integral model considers both single-stage and two-stage ignition processes, thus can be generally applied to different fuels such as paraffin, olefin, aromatics and alcohol. The model implementation is first validated in simulations of homogeneous charge compression ignition combustion for three different fuels, showing good accuracy in prediction of auto-ignition timing for fuels with either single-stage or two-stage ignition characteristics. Then, the L-W integral model is coupled with G-equation model to indicate end-gas auto-ignition and knock tendency in CFD simulations of a direct-injection spark-ignition engine. This modeling approach is about 10 times more efficient than the ones that based on detailed chemistry calculation and pressure oscillation analysis. Two fuels with same Research Octane Number (RON) but different octane sensitivity are studied, namely Co-Optima Alkylate and Co-Optima E30. Feed-forward neural network model in conjunction with multi-variable minimization technique is used to generate fuel surrogates with targets of matched RON, octane sensitivity and ethanol content. The CFD model is validated against experimental data in terms of pressure traces and heat release rate for both fuels under a wide range of operating conditions. The knock tendency — indicated by the fuel energy contained in the auto-ignited region — of the two fuels at different load conditions correlates well with the experimental results and the fuel octane sensitivity, implying the current knock modeling approach can capture the octane sensitivity effect and can be applied to further investigation on composition of octane sensitivity.
Gasoline Compression Ignition (GCI) on a Light-Duty Multi-Cylinder Engine Using a Wide Range of Fuel Reactivities and Heavy Fuel Stratification
Authors: Dempsey Adam B. , Curran Scott , Wagner Robert , Cannella William , Ickes Andrew
Published: December 2020

Many research studies have focused on utilizing gasoline in modern compression ignition engines to reduce emissions and improve efficiency. Collectively, this combustion mode has become known as gasoline compression ignition (GCI). One of the biggest challenges with GCI operation is maintaining control over the combustion process through the fuel injection strategy, such that the engine can be controlled on a cycle-by-cycle basis. Research studies have investigated a wide variety of GCI injection strategies (i.e., fuel stratification levels) to maintain control over the heat release rate while achieving low temperature combustion (LTC). This work shows that at loads relevant to light-duty engines, partial fuel stratification (PFS) with gasoline provides very little controllability over the timing of combustion. On the contrary, heavy fuel stratification (HFS) provides very linear and pronounced control over the timing of combustion. However, the HFS strategy has challenges achieving LTC operation due to the air handling burdens associated with the high EGR rates that are required to reduce NOx emissions to near zero levels. In this work, a wide variety of gasoline fuel reactivities (octane numbers ranging from < 40 to 87) were investigated to understand the engine performance and emissions of HFS-GCI operation on a multi-cylinder light-duty engine. The results indicate that over an EGR sweep at 4 bar BMEP, the gasoline fuels can achieve LTC operation with ultra-low NOx and soot emissions, while conventional diesel combustion (CDC) is unable to simultaneously achieve low NOx and soot. At 10 bar BMEP, all the gasoline fuels were compared to diesel, but using mixing controlled combustion and not LTC.
Statistical Quantification of Knock With Spark Ignition and Pre-Chamber Jet Ignition in a Light Duty Gasoline Engine
Authors: Yu Xin , Zhang Anqi , Baur Andrew , Voice Alexander , Engineer Nayan
Published: December 2020

Knock is a major challenge for high load operation of spark ignited gasoline engines with higher compression ratios, since the end-gas undergoes higher temperature and pressure trajectories during combustion. Pre-chamber combustion creates long-reach ignition jets that have the potential to mitigate knock due to their rapid consumption of end-gas. However, conventional pressure oscillation-based knock metrics may not accurately capture the end-gas autoignition severity in pre-chamber systems due to differences in ignition and combustion behavior. This work investigates the knock behavior of both traditional spark ignition and pre-chamber combustion (including different nozzle designs) in a high compression ratio engine fueled with regular octane certification gasoline. The data was analyzed using statistical methods to show the random nature of knock events. Detailed analysis was used to explain the pressure oscillations of both knocking and non-knocking cycles of pre-chamber jet combustion and show that conventional pressure oscillation-based knock metrics may not adequately quantify end-gas autoignition severity. A novel knock metric is introduced to avoid consideration of the non-knock related pressure oscillation and better quantify the end-gas autoignition severity. The new metric was used to explain the knock mitigation mechanism for pre-chamber jet combustion and demonstrate an additional pre-chamber jet ignition benefit of reduced combustion variability during engine operation with cooled exhaust gas circulation within its dilution limit.
The Sensitivity Study of a Mechanical Loss Model in Turbocharger System
Authors: Wang Haizhu , Burke Richard , Copeland Colin
Published: December 2020

3D modelling can be a very useful tool for optimising the design of turbocharger turbines. However, it is difficult to achieve high levels of correlation with experimental data which can undermine confidence in the 3D model results. A key difference between modelling and experiments is the way turbine efficiency is estimated: in CFD this is estimated directly from the shaft torque created by the turbine, however in experiments this is usually estimated based on the enthalpy rise measured at the compressor. This means that there is an inherent offset between the two which is the mechanical losses of the bearing system used to support the connecting shaft. The accuracy of the mechanical loss estimate can therefore play a critical role in the correlation of 3D modelling with experiments.

A 3D CFD model of a turbocharger turbine of a 1.5L gasoline engine has been coupled with a 0D mechanical losses model. The model comprises of seven parameters that characterise the bearing losses such as oil film thickness, bearing surface finish and clearances. A sensitivity study is conducted on these parameters to understand which are the critical aspects that should be parameterised and what relationship these parameters may have with the operating state of the turbocharger (shaft speed, shaft torque etc.). Experimental measurements were conducted for the same turbocharger to provide a baseline for assessing the impact of the mechanical losses model. These provide the boundary conditions to the CFD by ignoring the effects of heat transfer, and the results were compared to the 3D simulation results.
Design, Actuation, Experimental Setup and Testing of a 4-Cylinder Gasoline Spark Ignited Variable Compression Ratio Engine
Authors: Miller Tyler , Duncan Joel , Hensley William , Beard John , Worm Jeremy , Naber Jeffrey
Published: December 2020

The thermal efficiency of an Otto cycle engine is directly related to the compression ratio (CR). However, in a spark-ignited engine, the CR is often restricted by full load knock, thus limiting part load efficiency. A proof of concept design and experimental study has been conducted on a 4-cylinder naturally aspirated spark-ignited (SI) engine whereby a four-bar linkage mechanism has been implemented to vary the CR. The base engine selected was a production 2.0L GM-LNF SI 4-cylinder engine with a stock CR of 9.2:1 and with a bore and stroke of 86mm and 86mm, respectively. The engine was modified to allow the centerline axis of rotation of the crankshaft to translate in an arc about a fixed point. With the use of the four-bar mechanism, and larger dome volume pistons, a range of 8:1 to 11.5:1 CR was achieved.

The prototype VCR engine was tested and analyzed at three different CR’s at a fixed load of 600 kPa net indicated mean effective pressure gross (IMEPGROSS) at an engine speed of 1000 revolutions per minute (RPM). At this condition, a sweep of combustion phasing was conducted. with a stoichiometric air to fuel mixture for each case. The CR’s selected for engine testing were 8.7:1, 10.2:1, and 11.1:1. The processed data includes averaged cycle analysis of each of the test conditions including combustion phasing, combustion duration, and cycle variation. The combustion data was also analyzed to determine overall heat release, indicated gross, net, pumping mean effective pressures, and indicated fuel conversion efficiency for each of the CR’s. The studies show an indicated fuel conversion efficiency of 31.2% for the 8.7:1 CR. As the CR was increased to 10.2:1 and 11.1:1 the relative increase in efficiency was 7.1% and 9.7% respectively at MBT combustion phasing.
Modeling Nanosecond-Pulsed Spark Discharge and Flame Kernel Evolution
Authors: Kim Joohan , Gururajan Vyaas , Scarcelli Riccardo , Biswas Sayan , Ekoto Isaac
Published: December 2020

Dilute combustion, either using exhaust gas recirculation or with excess-air, is considered a promising strategy to improve the thermal efficiency of internal combustion engines. However, the dilute air-fuel mixture, especially under intensified turbulence and high-pressure conditions, poses significant challenges for ignitability and combustion stability, which may limit the attainable efficiency benefits. In-depth knowledge of the flame kernel evolution to stabilize ignition and combustion in a challenging environment is crucial for effective engine development and optimization. To date, comprehensive understanding of ignition processes that result in the development of fully predictive ignition models usable by the automotive industry does not yet exist. Spark-ignition consists of a wide range of physics that includes electrical discharge, plasma evolution, joule-heating of gas, and flame kernel initiation and growth into a self-sustainable flame. In this study, an advanced approach is proposed to model spark-ignition energy deposition and flame kernel growth. To decouple the flame kernel growth from the electrical discharge, a nanosecond pulsed high-voltage discharge is used to trigger spark-ignition in an optically accessible small ignition test vessel with a quiescent mixture of air and methane. Initial conditions for the flame kernel, including its thermodynamic state and species composition, are derived from a plasma-chemical equilibrium calculation. The geometric shape and dimension of the kernel are characterized using a multi-dimensional thermal plasma solver. The proposed modeling approach is evaluated using a high-fidelity computational fluid dynamics procedure to compare the simulated flame kernel evolution against flame boundaries from companion schlieren images.
Impact of face masks on voice radiation
Authors: Pörschmann Christoph , Lübeck Tim , Arend Johannes M.
Published: December 2020

With the COVID-19 pandemic, the wearing of face masks covering mouth and nose has become ubiquitous all around the world. This study investigates the impact of typical face masks on voice radiation. To analyze the transmission loss caused by masks and the influence of masks on directivity, this study measured the full-spherical voice directivity of a dummy head with a mouth simulator covered with six masks of different types, i.e., medical masks, filtering facepiece respirator masks, and cloth face coverings. The results show a significant frequency-dependent transmission loss, which varies depending on the mask, especially above 2 kHz. Furthermore, the two facepiece respirator masks also significantly affect speech directivity, as determined by the directivity index (DI). Compared to the measurements without a mask, the DI deviates by up to 7 dB at frequencies above 3 kHz. For all other masks, the deviations are below 2 dB in all third-octave frequency bands.
Individual variability in auditory feedback processing: Responses to real-time formant perturbations and their relation to perceptual acuity
Authors: Nault Daniel R. , Munhall Kevin G.
Published: December 2020

In this study, both between-subject and within-subject variability in speech perception and speech production were examined in the same set of speakers. Perceptual acuity was determined using an ABX auditory discrimination task, whereby speakers made judgments between pairs of syllables on a /ɛ/ to /æ/ acoustic continuum. Auditory feedback perturbations of the first two formants were implemented in a production task to obtain measures of compensation, normal speech production variability, and vowel spacing. Speakers repeated the word “head” 120 times under varying feedback conditions, with the final Hold phase involving the strongest perturbations of +240 Hz in F1 and −300 Hz in F2. Multiple regression analyses were conducted to determine whether individual differences in compensatory behavior in the Hold phase could be predicted by perceptual acuity, speech production variability, and vowel spacing. Perceptual acuity significantly predicted formant changes in F1, but not in F2. These results are discussed in consideration of the importance of using larger sample sizes in the field and developing new methods to explore feedback processing at the individual participant level. The potential positive role of variability in speech motor control is also considered.
A Second-Generation Fungerp Analog, SCY-247, Shows Potent
In Vivo
Activity in a Murine Model of Hematogenously Disseminated Candida albicans
Authors: Chu Sherman , Long Lisa , McCormick Thomas S. , Borroto-Esoda Katyna , Barat Stephen , Ghannoum Mahmoud A.
Published: December 2020

Echinocandins are a first-line therapy for
Candida
infections through their ability to inhibit the synthesis of polymer β-(1,3)-
d
-glucan. However, there has been an emergence of multidrug-resistant fungal species necessitating the development of novel antifungal agents to combat invasive fungal infections.
Encapsulation and Delivery of Therapeutic Phages
Authors: Loh Belinda , Gondil Vijay Singh , Manohar Prasanth , Khan Fazal Mehmood , Yang Hang , Leptihn Sebastian
Published: December 2020

Delivery of therapeutic compounds to the site of action is crucial. While many chemical substances such as beta-lactam antibiotics can reach therapeutic levels in most parts throughout the human body after administration, substances of higher molecular weight such as therapeutic proteins may not be able to reach the site of action (e.g., an infection) and are therefore ineffective.
Alteration of the Premature tRNA Landscape by Gammaherpesvirus Infection
Authors: Tucker Jessica M. , Schaller Aaron M. , Willis Ian , Glaunsinger Britt A.
Published: December 2020

Viral infection can dramatically change the gene expression landscape of the host cell, yet little is known regarding changes in noncoding gene transcription by RNA polymerase III (RNAPIII). Among these are transfer RNAs (tRNAs), which are fundamental in protein translation, yet whose gene regulatory features remain largely undefined in mammalian cells.
Poles Apart: Where and How Cells Construct Nisin
Authors: Hill Colin
Published: December 2020

Nisin is a 34-amino-acid lantibiotic that has been used commercially for almost a century as a food preservative. In order to produce active nisin,
Lactococcus lactis
requires an 11-gene operon that encodes proteins involved in modification, processing, transport, immunity, and regulation.
The Bactericidal Fatty Acid Mimetic 2CCA-1 Selectively Targets Pneumococcal Extracellular Polyunsaturated Fatty Acid Metabolism
Authors: Reithuber Elisabeth , Nannapaneni Priyanka , Rzhepishevska Olena , Lindgren Anders E. G. , Ilchenko Oleksandr , Normark Staffan , Almqvist Fredrik , Henriques-Normark Birgitta , Mellroth Peter
Published: December 2020

Fatty acid biosynthesis is an attractive antibiotic target, as it affects the supply of membrane phospholipid building blocks. In
Streptococcus pneumoniae
, it is not sufficient to target only the endogenous fatty acid synthesis machinery, as uptake of host fatty acids may bypass this inhibition.
Merkel Cell Polyomavirus Encodes Circular RNAs (circRNAs) Enabling a Dynamic circRNA/microRNA/mRNA Regulatory Network
Authors: Abere Bizunesh , Zhou Hongzhao , Li Jinghui , Cao Simon , Toptan Tuna , Grundhoff Adam , Fischer Nicole , Moore Patrick S. , Chang Yuan
Published: December 2020

Covalently closed circular RNAs were recently described in the human DNA tumor viruses Epstein-Barr virus (EBV), Kaposi’s sarcoma-associated herpesvirus (KSHV), and human papillomavirus (HPV). Here, we show that MCV, another DNA tumor virus, generates circRNAs from its early regulatory region in concert with T antigen linear transcripts.
Comprehensive Bioenergetic Evaluation of Microbial Pathway Variants in Syntrophic Propionate Oxidation
Authors: Patón Mauricio , Hernández Héctor H. , Rodríguez Jorge
Published: December 2020

In this work, an original methodology was developed that quantifies bioenergetically and physiologically feasible net ATP yields for large numbers of microbial metabolic pathways and their variants under different conditions. All variants are evaluated, which ensures global optimality in finding the pathway variant(s) leading to the highest ATP yield.
A Subset of Roux-en-Y Gastric Bypass Bacterial Consortium Colonizes the Gut of Nonsurgical Rats without Inducing Host-Microbe Metabolic Changes
Authors: Liu Zhigang , Coales Isabelle , Penney Nicholas , McDonald Julie A. K. , Phetcharaburanin Jutarop , Seyfried Florian , Li Jia V.
Published: December 2020

Roux-en-Y gastric bypass (RYGB) surgery results in a long-term gut bacterial shift toward
Gammaproteobacteria
in both patients and rodents. The contribution of this compositional shift, or the RYGB bacterial consortium, to the metabolic benefit of the surgery remains debatable.
Supplemental Material: A detrital zircon test of large-scale terrane displacement along the Arctic margin of North America
Authors: Gibson Timothy , al. et
Published: December 2020

Supplemental methods, sample descriptions, and U-Pb results, as well as Figures S1 and S2 and Tables S1–S3.
Supplemental Material: Anisovolumetric weathering in granitic saprolite controlled by climate and erosion rates
Authors: Riebe Clifford , al. et
Published: December 2020

Supplemental methods and Tables S1–S4.
Supplemental Material: Total organic carbon and the preservation of organic-walled microfossils in Precambrian shale
Authors: Woltz Christina , al. et
Published: December 2020

Sample information, methodology, TOC analyses, criteria for preservational quality, Figures S1–S8, and Tables S1–S4.
Supplemental Material: Experimental constraints on nonskeletal CaCO3 precipitation from Proterozoic seawater
Authors: Roest-Ellis Sascha , al. et
Published: December 2020

Experimental method with figures, solution compositions, and solid sample characterization.
Supplemental Material: Timing and amount of southern Cascadia earthquake subsidence over the past 1700 years at northern Humboldt Bay, California, USA
Authors: Padgett Jason S. , al. et
Published: December 2020

Tables S1–S32 and Figures S1–S7.
Comprehensive evaluation of bone health using DXA and pQCT in an Indian boy with osteogenesis imperfecta
Authors: Karguppikar Madhura Bharat , Ekbote Veena , Khadilkar Anuradha , Khadilkar Vaman
Published: December 2020

We present a 9-year-old male child having history of fractures on trivial trauma with a family history of the same. He was treated for osteogenesis imperfecta (OI; zolendronate, calcium and vitamin D) and showed clinical improvement. On evaluating his bone health using dual energy X-ray absorptiometry and peripheral quantitative CT, we found that the child had bone density within the reference range but a smaller bone mass for his height, low muscle mass and thin bones with a lower strength strain index in comparison with healthy children. Our case suggests that treatment with bisphosphonates results in increase in bone density; however, bones remain thin and the lean body mass in these children may also be low. Controlled physical activity to improve muscle health and newer approaches to improve bone geometry would result in better bone health in children with OI.
Poorly differentiated mucoepidermoid carcinoma of the thyroid
Authors: Lee Kristina , Mirza Omar , Dobbs Sian , Jayaram Sharan
Published: December 2020

Mucoepidermoid carcinomas (MECs) are the most common malignant tumour of the salivary glands. MECs have also been reported to occur in atypical sites. Primary MECs of the thyroid gland are extremely rare, accounting for 0.5% of thyroid malignancies with approximately 48 cases reported in the literature. In most cases, these are low-grade neoplasms with good long-term prognosis. We present the case of a 74-year-old patient with poorly differentiated MEC of the thyroid gland, which behaved aggressively resulting in rapid decline and death of the patient. The exact pathophysiology of the disease remains unclear and there is no consensus on the optimal treatment for this histological subtype. Recognition and diagnosis of this rare neoplasm are important as this can help guide optimal treatment, although in high-grade poorly differentiated cases, treatment options remain limited.
A novel case of congenital spinocerebellar ataxia 5: further support for a specific phenotype associated with the p.(Arg480Trp) variant inSPTBN2
Authors: Zonta Andrea , Brussino Alessandro , Dentelli Patrizia , Brusco Alfredo
Published: December 2020

A 4-year-old girl was referred to the geneticist with a history of ataxia associated with intention tremor of the hands, strabismus and hypermetropy. Her symptoms presented about 2 years earlier with inability to walk unaided and lower limbs hypotonia. Cognitive functions were normal. Brain MRI showed a cerebellar and vermian hypoplasia with enlargement of both the cerebrospinal fluid spaces and the IV brain ventricle. Family history was unremarkable. A genetic screening using a 42-gene panel for hereditary ataxia/spastic paraparesis identified ade novoc.1438C>T - p.(Arg480Trp) missense change in theSPTBN2gene (NM_006946.2). This variant is reported to be associated with congenital ataxia, later evolving into ataxia and intellectual disability. This case further supports the existence of a specificSPTBN2p.(Arg480Trp)-associated phenotype, with ade novorecurrence of this variant in the heterozygous state.
Non-bacterial thrombotic endocarditis: a rare presentation and literature review
Authors: Patel Maulin J , Elzweig Joel
Published: December 2020

A 66-year-old woman with a remote history of breast cancer and prior tobacco use presented to the hospital with chest pain. She was found to have an elevated troponin consistent with a diagnosis of a non-ST segment elevation myocardial infarction (NSTEMI). A left heart catheterisation revealed non-obstructive coronary disease, and subsequent transthoracic and transoesophageal echocardiograms demonstrated vegetations on both the mitral and aortic valves. Multiple blood cultures showed no growth raising suspicion for non-bacterial thrombotic endocarditis (NBTE). A CT of the chest, abdomen and pelvis was obtained that was consistent with metastatic pancreatic cancer. Her hospital course was complicated by recurrent embolic strokes leading to a rapid clinical deterioration. As a result, she was transitioned to comfort measures and passed away shortly thereafter. To our knowledge, this is the first reported case of an NSTEMI as the initial presentation of NBTE due to underlying malignancy.