bluuebunny/crossref_metadata_2025 huggingface dataset:
Turbulent Flame Speed and Flame Characteristics of Lean Premixed H2-CH4 Flames at Moderate Pressure Levels
Authors: Faldella Filippo , Eisenring Sebastian , Kim Taesung , Doll Ulrich , Jansohn Peter
Published: September 2023

Carbon dioxide emissions in gas turbine power generation can be reduced by adding an increasing amount of hydrogen to the existing natural gas-fueled combustion systems. To enable safe operation, more insight on how H2 addition affects turbulent flame speed and other important flame characteristics is needed. In this work, the investigation of hydrogen addition effects on certain flame properties has been carried out in a high-pressure axial-dump combustor at gas turbine relevant conditions. OH planar laser induced fluorescence (PLIF) was applied to retrieve flame front contours and turbulent flame speed. The results show that as the concentration of hydrogen in the fuel mixture increases, turbulent flame speed and flame characteristics change drastically. Two main regimes can be identified: From 0 to 50% vol. Hydrogen, the turbulent flame speed increases weakly in an almost linear fashion, while from 50% vol. to 100% vol. the trend sharply changes and the higher reactivity of hydrogen, combined with a lower Lewis number, cause thermal-diffusive instability and preferential diffusion effects to become increasingly strong, leading to very high burning rates. The presented results help to understand and to define the relevant modifications that are necessary to successfully operate gas turbine combustor systems with high H2 content fuels.
Integrated Aerodynamic and Mechanical Design of a Large-Scale Axial Turbine Operating With A Supercritical Carbon Dioxide Mixture
Authors: Abdeldayem Abdelrahman , Paggini Andrea , Diurno Tommaso , Orazi Claudio , White Martin , Ruggiero Marco , Sayma Abdulnaser
Published: September 2023

In this paper, the design of a large-scale axial turbine operating with supercritical carbon dioxide (sCO2) blended with sulfur dioxide (SO2) is presented considering aerodynamic and mechanical design aspects as well as the integration of the whole turbine assembly. The turbine shaft power is 130 MW, designed for a 100 MWe concentrated-solar power plant with turbine inlet conditions of 239.1 bar and 700 °C, total-to-static pressure ratio of 2.94, and mass-flow rate of 822 kg/s. The aerodynamic flow path, obtained in a previous study, is first summarized before the aerodynamic performance of the turbine is evaluated using both steady-state and unsteady three-dimensional numerical models. Whole-annulus unsteady simulations are performed for the last turbine stage and the exhaust section to assess the unsteady loads on the rotor due to downstream pressure field distortion and to assess the aerodynamic losses within the diffuser and exhaust section. The potential low engine order excitation at the last rotor stage natural frequency modes due to downstream pressure distortion is assessed. The design of the turbine assembly is constrained by current manufacturing capabilities and the properties of the proposed working fluid. High-level flow-path design parameters, such as pitch diameter and number of stages, are established considering a trade-off between weight and footprint, turbine efficiency, and rotordynamics. Rotordynamic stability is assessed considering the high fluid density and related cross coupling effects. Finally, shaft end sizing, cooling system design, and the integration of dry gas seals are discussed.
Performance Investigation of Stator-Less and Blade-Less Radial Expander
Authors: Renuke Avinash , Traverso Alberto , Reggio Federico , Pascenti Matteo , Silvestri Paolo
Published: September 2023

Interests in small-scale turbomachinery are gaining momentum, particularly around waste heat recovery using Organic Rankine Cycle (ORC), energy harvesting, pico-hydro, refrigeration and heat pumps and small-scale power generation. These applications demand to have economical, simple construction, and reasonably efficient machines. The performance of bladed turbomachine at a small scale is poor mainly due to viscous losses and relatively large clearances. In some cases, like ORC, it requires a lubrication system, making it complex and costly. Bladeless or Tesla turbomachinery is seen as one of the solutions for these applications due to its simple construction and cost-effectiveness. However, the experimental efficiency of the bladeless turbines/compressors is found in the low region, <40%. In this article, the performance of a bladeless turbine is investigated using a vaneless volute configuration, making the turbine stator-less (vaneless volute) and bladeless (vaneless rotor). This study presents numerical and experimental performance investigation with a volute as a stator of the bladeless rotor. Three-dimensional (3D) Numerical results show very promising performance of the turbine with total to static efficiencies calculated above 65%. In the second part of the article, turbine prototype components, assembly, and test setup are discussed. Experimental maximum efficiency of 41.5 ± 0.88% at 3.5 kg/s@5000 rpm and power of 915 W is obtained. This is the highest recorded efficiency for the Tesla turbine in peer-reviewed research. The overall turbine performance from 3D numerical simulation with ventilation and mechanical losses is compared with experimental results. This work demonstrates that the proposed stator-less/volute configuration provides an efficient way for bladeless or Tesla turbines, particularly for low-head applications.
Combined Joule-Humphrey-Recuperator Cycle: Performance and Parametric Analysis Evaluation Toward More Efficient Air Transportation
Authors: Saavedra Jorge , Cadarso Luis
Published: September 2023

A three-stream combined Joule-Humphrey cycle that employs a heat recovery stream to function as a recuperator is presented. Based on an in-house developed thermodynamic performance tool, the operation of a modified dual-shaft turbofan engine is proposed. The engine core is modified by adding an intercooler and a reheating chamber to approach isothermal compression and expansion processes. A fraction of the primary flow is introduced into a reheat chamber that uses rotating detonation combustion (RDC) technology. The outflow of the RDC is then merged with the rest of the nucleus current before being discharged to the next turbine stage. The overall system behavior is captured by means of a nonlinear mathematical model featuring eight decision variables, including mass flow rates and compression ratios. A parametric analysis identifies the operational and performance envelope of the proposed engine concept. Ultimately, the model is endowed with an objective function, which includes global efficiency and thrust looking for an operation regime that boosts the thermodynamic performance. A generalized reduced gradient based algorithm is used to solve the nonlinear model, where each iteration solves a linearly constrained subproblem to generate a search direction. The performance and operational envelope presented here could be used as guidance for others considering the implementation of any of the discussed Joule cycle modifications or assessing the cost-effective balance of their use.
A Computational Fluid Dynamics-Based Small-Scale Combustor Design Optimization Utilizing a Many-Objective Evolutionary Algorithm
Authors: Briones Alejandro M. , Paxton Brendan T. , Rankin Brent A.
Published: September 2023

This work demonstrates the capability of an open-source autonomous computational fluid dynamics (CFD) metamodeling environment (OpenACME) for optimizing small-scale combustor designs. OpenACME couples several object-oriented programing open-source codes for CFD-assisted design using a decomposition-based many-objective evolutionary algorithm. The CFD is based on steady, incompressible, three-dimensional simulations with k–ω SST RANS and flamelet/progress variable combustion model. There are five unconstrained design variables based on combustor liner dilution hole diameters. The CFD results are compared with existing experimental data in terms of combustion efficiency as a function of severity parameter. The comparison demonstrates that the CFD methods capture combustion efficiency trends. Next, more than 500 combustor designs are evaluated with OpenACME. A Pareto Frontier is generated in terms of combustion efficiency, pattern factor, and total pressure losses. Pseudo-weights are used to select a nondominated Pareto Frontier design point for future fabrication and experimental testing. OpenACME is demonstrated to be a viable tool for small-scale combustor design optimization.
Temperature-Humidity-Bias Testing and Life Prediction Modeling for Electrochemical Migration in Aerosol-Jet Printed Circuits
Authors: Zhao Beihan , Bharamgonda Aniket , Quinn Edwin , Stackhouse George , Fleischer Jason , Osterman Michael , Azarian Michael H. , Hines Daniel R. , Das Siddhartha , Dasgupta Abhijit
Published: September 2023

Aerosol-Jet Printing (AJP) technology, applied to the manufacturing of printed hybrid electronics (PHE) devices, has the capability to fabricate highly complex structures with resolution in the tens-of-microns scale, creating new possibilities for the fabrication of electronic devices and assemblies. The widespread use of AJP in fabricating PHE and package-level electronics necessitates a thorough assessment of not only the performance of AJP printed electronics but also their reliability under different kinds of life-cycle operational and environmental stresses. One important hindrance to the reliability and long-term performance of such AJP electronics is electrochemical migration (ECM). ECM is an important failure mechanism in electronics under temperature and humidity conditions because it can lead to conductive dendritic growth, which can cause dielectric breakdown, leakage current, and unexpected short circuits. In this paper, the ECM propensity in conductive traces printed with AJP process, using silver-nanoparticle (AgNP) based inks, was experimentally studied using temperature-humidity-bias (THB) testing of printed test coupons. Conductive dendritic growth with complex morphologies was observed under different levels of temperature, humidity, and electric bias in the THB experiments. Weibull statistics are used to quantify the failure data, along with the corresponding confidence bounds to capture the uncertainty of the Weibull distribution. A nonmonotonic relationship between time-to-failure and electric field strength was noticed. An empirical acceleration model for ECM is proposed, by combining the classical Peck's model with a quadratic polynomial dependence on electric field strength. This model provides good estimate of acceleration factors for use conditions where the temperature, humidity, and electrical field are within the tested range, but should be extrapolated with care beyond the tested range.
Damping and Stiffness Mistuning Effects in a Bladed Disk With Varied Disk Coupling
Authors: Krizak Troy , Kurstak Eric , D'Souza Kiran
Published: September 2023

Component mode mistuning (CMM) is a well-known, well documented reduced order modeling technique that effectively models small variations in blade-to-blade stiffness for bladed disks. In practice, bladed disks always have variations, referred to as mistuning, and are a focus of a large amount of research. One element that is commonly ignored from small mistuning implementations is the variation within the blade-to-blade damping values. This work seeks to better understand the effects of damping mistuning by utilizing both structural and proportional damping formulations. This work builds from previous work that implemented structural damping mistuning reduced order models formulated based on CMM. A similar derivation was used to create reduced order models with a proportional damping formulation. The damping and stiffness mistuning values investigated in this study were derived using measured blade natural frequencies and damping ratios from high-speed rotating experiments on freestanding blades. The two separate damping formulations that are presented give very similar results, enabling the user to select their preferred method for a given application. A key parameter investigated in this work is the significance of blade-to-blade coupling. The blade-to-blade coupling study investigates how the level of coupling impacts damping mistuning effects versus applying average damping to the bladed disk model. Also, the interaction of stiffness and damping mistuning is studied. Monte Carlo simulations were carried out to determine amplification factors, or the ratio of mistuned blade responses to tuned blade responses, for various mistuning levels and patterns.
Centrifugal Compressor Surge in Innovative Heat Pump: Fluid Dynamic and Vibrational Analysis
Authors: Ferrando Marco , Reboli Tommaso , Reggio Federico , Niccolini Carlo Alberto , Silvestri Paolo , Traverso Alberto , Sishtla Vishnu
Published: September 2023

In the current energy scenario, it is necessary to reduce fossil fuel consumption to achieve the far-sighted and stringent decarbonization goals. To date, heat is mainly produced through fossil fuels. Alternatively, electrically driven heat pumps can exploit renewable power to recover environmental and waste heat, offering energy efficient and environmentally friendly heating and cooling for applications ranging from domestic and commercial buildings to process industries. For this reason, they are expected to play a primary role in complementing or displacing natural gas boilers in the residential and industrial sectors in the near future. Centrifugal compressors are already used as prime movers of the working fluid in heat pumps, thanks to their industrial replicability, compact size, affordable costs, and good performance in terms of efficiency and low noise. However, they are subject to instabilities such as surge and stall like any other dynamic compressor and these phenomena develop quite differently than in classic open-loop systems such as gas turbines. In fact, such peculiarity is mainly due to the closed-loop configuration with real gases in two-phase conditions, occurring in typical heat pump cycles. In addition, heat exchangers also contribute to make these phenomena different from what is commonly studied. Compressor surge in closed-loop heat pump systems has received lower attention than other applications by the engineering community, lacking dedicated experimental characterization, and clear exposition of the phenomenon. The aim of this paper is to experimentally investigate the behavior of a centrifugal compressor installed into an innovative close loop heat pump system under stable and unstable conditions from both vibrational and fluid-dynamic points of view. The impact of the main process parameters on the evolution of the instability is shown, highlighting how surge cycles change by varying system operating conditions. The energy contents of surge cycles and pressure fluctuations are highlighted, using data postprocessing techniques such as fast Fourier transform and phase locked average. The vibro-acoustic analysis enrich the comprehension of the phenomena. The experimental results shown in this paper can be a basis for the future development of validated mathematical models of closed-loop heat pumps systems equipped with dynamic compressors operating under stable and unstable operating conditions.
Techno-Economic Analysis of a Physisorption-Based Hydrogen Storage System
Authors: Schueler Yannik , Otto Marcel , Kapat Jayanta , Schmitt Joshua
Published: September 2023

Alternative long-term storage of energy is becoming increasingly important due to climate change. Hydrogen-based storage technologies have long been considered promising alternatives to batteries. However, the different forms of hydrogen storage have various disadvantages and are still comparatively expensive. As an alternative, this paper deals with a new concept for hydrogen storage, the Cryogenic Flux Capacitor (CFC). It is intended as an intermediate between high-pressure and liquid storage to exploit the advantages and reduce the disadvantages. This paper ranks the CFC technology against the others. For this purpose, it investigates the economic viability and the specific application as a grid-connected system. A complete system from hydrogen production and storage to conversion into electrical energy is considered. In detail, the costs for storage and storage time are compared, and the size scaling of a CFC-based system as a grid-connected system is examined. The Levelized Costs of Energy (LCOE) are calculated and compared as a benchmark. It turns out that a CFC-based storage system also requires a tremendous amount of energy in the form of liquid nitrogen and the associated operational costs for cooling down the hydrogen. Nevertheless, the overall operating costs are between high-pressure and liquid hydrogen storage. Most surprising is the LCOE, which, at 0.192 $/kWh–0.234 $/kWh, is well within the range of the other storage technologies. As a grid-connected storage system, CFC technology can be used as a small- to a medium-scale energy storage system, e.g., to serve smaller neighborhoods.
Performance Evaluation of Additively Manufactured and Hybrid Indexable Milling Tools in Machining of AISI4140+QT and Ti-6Al-4V
Authors: Kelliger Tobias , Meurer Markus , Bergs Thomas
Published: September 2023

Additively manufactured (AM) cutting tools enable new design concepts in tool development concerning lightweight construction, damping behavior, and internal cutting fluid supply. So far, the impact of the layer-by-layer manufacturing technique onto the tool performance during machining of aerospace materials is widely unknown. In this study, the performance characteristics of AM indexable milling tools were investigated and compared to a conventionally manufactured tool of the same geometry. The AM tools were manufactured by laser powder bed fusion (LPBF) from a newly developed bainitic steel alloy. All tools were analyzed with two main focuses. Outside the machine tool, geometrical characteristics and mechanical properties were taken into account. Inside the machine tool, during roughing of AISI4140+QT (42CrMo4+QT) and Ti-6Al-4V (ASTM Ti-Grade 5), tool wear, cutting forces, surface roughness and vibration behavior were evaluated. Three tool concepts were compared, a conventional tool, an AM tool, and a hybrid tool with a conventionally manufactured preform and an AM head. Differences in the performance behavior could be traced back mainly to geometrical inaccuracies caused during postprocessing of the tools. Thus, LPBF-manufactured basic bodies seem to meet the requirements as applications for indexable milling tools. Based on this work, future investigations using AM cutting tools can be carried out assuming a negligible influence of the manufacturing technique onto the tool performance during machining.
A Novel Port to Facilitate Magnetic Hyperthermia Therapy for Glioma
Authors: Rodriguez Benjamin , Campbell Peter , Borrello Joseph , Odland Ian , Williams Tyree , Hrabarchuk Eugene I. , Young Tirone , Sharma Anirudh , Schupper Alexander J. , Rapoport Benjamin , Ivkov Robert , Hadjipanayis Constantinos
Published: September 2023

High-grade gliomas (HGG) are the most common primary brain malignancy and continue to be associated with a dismal prognosis (median survival rate of 15–18 months) with standard of care therapy. Magnetic hyperthermia therapy (MHT) is an emerging intervention that leverages the ferromagnetic properties of magnetic iron-oxide nanoparticles (MIONPs) to target cancer cells that are otherwise left behind after resection. We report a novel port device to facilitate localization, delivery, and temperature measurement of MIONPs within a target lesion for MHT therapy. We conducted an in-depth literature and intellectual property review to define specifications of the conceived port device. After setting the design parameters, a thorough collaboration with neurological surgeons guided the iterative modeling process. A prototype was developed using Fusion 360 (Autodesk, San Rafael, CA) and printed on a Form 3 printer (Formlabs, Medford, MA) in Durable resin. The prototype was then tested in a phantom skull printed on a Pro-Jet 660Pro 3D printer (3D Systems, Rock Hill, SC) and a brain model based on mechanical and electrochemical properties of native brain tissue. This phantom underwent MHT heating tests using an alternating magnetic field (AMF) sequence based on current MHT workflow. Successful localization, delivery, and temperature measurement were demonstrated. The purpose of this study was twofold: first, to create and validate the procedural framework for a novel device, providing the groundwork for an upcoming comprehensive animal trial and second, to elucidate a cooperative approach between engineers and clinicians that propels advancements in medical innovation.
A Novel Fiber-Reinforced Poroviscoelastic Bovine Intervertebral Disc Finite Element Model for Organ Culture Experiment Simulations
Authors: Ristaniemi Aapo , Šećerović Amra , Grad Sibylle , Ferguson Stephen J.
Published: September 2023

Intervertebral disc (IVD) degeneration and methods for repair and regeneration have commonly been studied in organ cultures with animal IVDs under compressive loading. With the recent establishment of a novel multi-axial organ culture system, accurate predictions of the global and local mechanical response of the IVD are needed for control system development and to aid in experiment planning. This study aimed to establish a finite element model of bovine IVD capable of predicting IVD behavior at physiological and detrimental load levels. A finite element model was created based on the dimensions and shape of a typical bovine IVD used in the organ culture. The nucleus pulposus (NP) was modeled as a neo-Hookean poroelastic material and the annulus fibrosus (AF) as a fiber-reinforced poroviscoelastic material. The AF consisted of 10 lamella layers and the material properties were distributed in the radial direction. The model outcome was compared to a bovine IVD in a compressive stress-relaxation experiment. A parametric study was conducted to investigate the effect of different material parameters on the overall IVD response. The model was able to capture the equilibrium response and the relaxation response at physiological and higher strain levels. Permeability and elastic stiffness of the AF fiber network affected the overall response most prominently. The established model can be used to evaluate the response of the bovine IVD at strain levels typical for organ culture experiments, to define relevant boundaries for such studies, and to aid in the development and use of new multi-axial organ culture systems.
Native mitral valve infective endocarditis: a significant contribution of 3d-transthoracic echocardiography
Authors: Becic Tina , Perkovic-Avelini Ruzica , Fabijanic Damir
Published: September 2023

.
Recurrent right atrial thrombosis in Ebstein's anomaly
Authors: Jiang Fenglin , Zhu Jingjun
Published: September 2023

.
Optical and atomic decoherence in quantum nondemolition measurement induced atomic ensemble entanglement
Authors: Gao Shuai , Li Shuang , Chaudhary Manish , Prest Matthew , Ilo-Okeke Ebubechukwu O. , Ivannikov Valentin , Byrnes Tim
Published: September 2023

We study the effects of optical and atomic decoherence in entangled atomic ensembles produced via quantum nondemolition (QND) measurements. We examine potentially experimentally detrimental effects, such as optical phase diffusion, photon loss and gain, and atomic dephasing. For the optical decoherence channels, we use the technique of integration within ordered operators to obtain the associated Kraus operators. We analyze the effect of different decoherence channels on various quantities, such as the variances of the spin operators, entanglement and correlation criteria, logarithmic negativity, and the Bell–CHSH inequality. We generally find a smooth decay of correlations and entanglement in the presence of decoherence. In the short interaction time range, we find that various quantities show signals consistent with, and showing that entanglement exists under all three types of decoherence. Our results show that QND measurements are one of the most promising methods for entanglement generation between two Bose–Einstein condensates.
Solid-source metal-organic MBE for elemental Ir and Ru films
Authors: Nair Sreejith , Noordhoek Kyle , Lee Dooyong , Bartel Christopher J. , Jalan Bharat
Published: September 2023

Thin films of elemental metals play a very important role in modern electronic nano-devices as conduction pathways, spacer layers, spin-current generators/detectors, and many other important functionalities. In this work, by exploiting the chemistry of solid metal-organic source precursors, we demonstrate the molecular beam epitaxy synthesis of elemental Ir and Ru metal thin films. The synthesis of these metals is enabled by thermodynamic and kinetic selection of the metal phase as the metal-organic precursor decomposes on the substrate surface. Film growth under different conditions was studied using a combination of in situ and ex situ structural and compositional characterization techniques. The critical role of substrate temperature, oxygen reactivity, and precursor flux in tuning film composition and quality is discussed in the context of precursor adsorption, decomposition, and crystal growth. Computed thermodynamics quantifies the driving force for metal or oxide formation as a function of synthesis conditions and changes in chemical potential. These results indicate that bulk thermodynamics are a plausible origin for the formation of Ir metal at low temperatures, while Ru metal formation is likely mediated by kinetics.
Cortical circuits modulate mouse social vocalizations
Authors: Gan-Or Benjamin , London Michael
Published: September 2023

Vocalizations provide a means of communication with high fidelity and information rate for many species. Diencephalon and brainstem neural circuits have been shown to control mouse vocal production; however, the role of cortical circuits in this process is debatable. Using electrical and optogenetic stimulation, we identified a cortical region in the anterior cingulate cortex in which stimulation elicits ultrasonic vocalizations. Moreover, fiber photometry showed an increase in Ca
2+
dynamics preceding vocal initiation, whereas optogenetic suppression in this cortical area caused mice to emit fewer vocalizations. Last, electrophysiological recordings indicated a differential increase in neural activity in response to female social exposure dependent on vocal output. Together, these results indicate that the cortex is a key node in the neuronal circuits controlling vocal behavior in mice.
Emotional content and sharing on Facebook: A theory cage match
Authors: Paletz Susannah B. F. , Johns Michael A. , Murauskaite Egle E. , Golonka Ewa M. , Pandža Nick B. , Rytting C. Anton , Buntain Cody , Ellis Devin
Published: September 2023

While emotional content predicts social media post sharing, competing theories of emotion imply different predictions about how emotional content will influence the virality of social media posts. We tested and compared these theoretical frameworks. Teams of annotators assessed more than 4000 multimedia posts from Polish and Lithuanian Facebook for more than 20 emotions. We found that, drawing on semantic space theory, modeling discrete emotions independently was superior to models examining valence (positive or negative), activation/arousal (high or low), or clusters of emotions and was on par with but had more explanatory power than a seven basic emotion model. Certain discrete emotions were associated with post sharing, including both positive and negative and relatively lower and higher activation/arousal emotions (e.g., amusement, cute/kama muta, anger, and sadness) even when controlling for number of followers, time up, topic, and Facebook angry reactions. These results provide key insights into better understanding of social media post virality.
Structural characterization of human urea transporters UT-A and UT-B and their inhibition
Authors: Chi Gamma , Dietz Larissa , Tang Haiping , Snee Matthew , Scacioc Andreea , Wang Dong , Mckinley Gavin , Mukhopadhyay Shubhashish M. M. , Pike Ashley C. W. , Chalk Rod , Burgess-Brown Nicola A. , Timmermans Jean-Pierre , van Putte Wouter , Robinson Carol V. , Dürr Katharina L.
Published: September 2023

In this study, we present the structures of human urea transporters UT-A and UT-B to characterize them at molecular level and to detail the mechanism of UT-B inhibition by its selective inhibitor, UTB
inh
-14. High-resolution structures of both transporters establish the structural basis for the inhibitor’s selectivity to UT-B, and the identification of multiple binding sites for the inhibitor will aid with the development of drug lead molecules targeting both transporters. Our study also discovers phospholipids associating with the urea transporters by combining structural observations, native MS, and lipidomics analysis. These insights improve our understanding of urea transporter function at a molecular level and provide a blueprint for a structure-guided design of therapeutics targeting these transporters.
The illusory end of stop and frisk in Chicago?
Authors: Hausman David , Kronick Dorothy
Published: September 2023

Critics of stop and frisk have heralded its recent demise in several large U.S. cities. Proponents of stop and frisk respond that when the practice ends, crime increases. Both groups typically assume that the end of stop and frisk reduces the number of police-civilian interactions. We find otherwise in Chicago: The decline in pedestrian stops coincided with an increase in traffic stops. Qualitative evidence suggests that the Chicago Police deliberately switched from pedestrian to traffic stops. Quantitative data are consistent with this hypothesis: As stop and frisk ended, Chicago Police traffic stops diverged (in quantity and composition) from those of another enforcement agency in Chicago, and the new traffic stops affected the same types of Chicagoans who were previously subject to pedestrian stops.
Aquatic plant wax hydrogen and carbon isotopes in Greenland lakes record shifts in methane cycling during past Holocene warming
Authors: McFarlin Jamie M. , Axford Yarrow , Kusch Stephanie , Masterson Andrew L. , Lasher G. Everett , Osburn Magdalena R.
Published: September 2023

Predicting changes to methane cycling in Arctic lakes is of global concern in a warming world but records constraining lake methane dynamics with past warming are rare. Here, we demonstrate that the hydrogen isotopic composition (δ
2
H) of mid-chain waxes derived from aquatic moss

clearly decouples from precipitation during past Holocene warmth and instead records incorporation of methane in plant biomass. Trends in δ
2
H
moss
and δ
13
C
moss
values point to widespread Middle Holocene (11,700 to 4200 years ago) shifts in lake methane cycling across Greenland during millennia of elevated summer temperatures, heightened productivity, and lowered hypolimnetic oxygen. These data reveal ongoing warming may lead to increases in methane-derived C in many Arctic lakes, including lakes where methane is not a major component of the C cycle today. This work highlights a previously unrecognized mechanism influencing δ
2
H values of mid-chain wax and draws attention to the unquantified role of common aquatic mosses as a potentially important sink of lake methane across the Arctic.
Microevolutionary patterns in ecotypes of the symbiotic cyanobacterium UCYN-A revealed from a Northwest Atlantic coastal time series
Authors: Robicheau Brent M. , Tolman Jennifer , Desai Dhwani , LaRoche Julie
Published: September 2023

UCYN-A is a globally important nitrogen-fixing symbiotic microbe often found in colder regions and coastal areas where nitrogen fixation has been overlooked. We present a 3-year coastal Northwest Atlantic time series of UCYN-A by integrating oceanographic data with weekly
nifH
and16
S
rRNA gene sequencing and quantitative PCR assays for UCYN-A ecotypes. High UCYN-A relative abundances dominated by A1 to A4 ecotypes reoccurred annually in the coastal Northwest Atlantic. Although UCYN-A was detected every summer/fall, the ability to observe separate ecotypes may be highly dependent on sampling time given intense interannual and weekly variability of ecotype-specific occurrences. Additionally, much of UCYN-A’s rarer diversity was populated by short-lived neutral mutational variants, therefore providing insight into UCYN-A’s microevolutionary patterns. For instance, rare ASVs exhibited community composition restructuring annually, while also sharing a common connection to a dominant ASV within each ecotype. Our study provides additional perspectives for interpreting UCYN-A intraspecific diversity and underscores the need for high-resolution datasets when deciphering spatiotemporal ecologies within UCYN-A.
N-linked glycoproteins and host proteases are involved in swine acute diarrhea syndrome coronavirus entry
Authors: Chen Ying , Liu Xi , Zheng Jiang-Nan , Yang Li-Jun , Luo Yun , Yao Yu-Lin , Liu Mei-Qin , Xie Ting-ting , Lin Hao-Feng , He Yan-Tong , Zhou Peng , Hu Ben , Tian Rui-Jun , Shi Zheng-Li
Published: September 2023

Swine acute diarrhea syndrome coronavirus (SADS-CoV) is highly pathogenic to piglets and poses a major threat to the swine industry. SADS-CoV has a wide cell tropism and pathogenic potential in younger animals. Therefore, understanding how SADS-CoV enters cells is essential for curbing its re-emergence and spread. Here, we report that tunicamycin, an N-linked glycoprotein inhibitor, inhibited the attachment of SADS-CoV to host cells, suggesting that the SADS-CoV receptor may be an N-linked glycoprotein but not Neu5Gc or Neu5Ac. Moreover, we found that exogenous trypsin, endogenous serine protease, cathepsin B, cathepsin L, and lysosomal acidification triggered SADS-CoV entry into cells. These findings improve our understanding of the molecular mechanisms underlying SADS-CoV entry and provide insights into the development of potential antiviral targets against SADS-CoV.

IMPORTANCE

Gaining insight into the cell-entry mechanisms of swine acute diarrhea syndrome coronavirus (SADS-CoV) is critical for investigating potential cross-species infections. Here, we demonstrated that pretreatment of host cells with tunicamycin decreased SADS-CoV attachment efficiency, indicating that N-linked glycosylation of host cells was involved in SADS-CoV entry. Common N-linked sugars Neu5Gc and Neu5Ac did not interact with the SADS-CoV S1 protein, suggesting that these molecules were not involved in SADS-CoV entry. Additionally, various host proteases participated in SADS-CoV entry into diverse cells with different efficiencies. Our findings suggested that SADS-CoV may exploit multiple pathways to enter cells, providing insights into intervention strategies targeting the cell entry of this virus.
Interferon regulatory factor 7 modulates virus clearance and immune responses to alphavirus encephalomyelitis
Authors: Troisi Elizabeth M. , Nguyen Benjamin H. , Baxter Victoria K. , Griffin Diane E.
Published: September 2023

Central nervous system (CNS) infection with Sindbis virus (SINV), the prototypic alphavirus, results in encephalomyelitis in a well-established mouse model that is used to characterize immune factors important in controlling viral infection in neurons. We have previously shown that interferon regulatory factor (IRF) 7 is required for survival from SINV encephalomyelitis, as mice deficient in IRF7 (
Irf7
−/−
) develop paralysis and fatal disease within 7–8 days after infection without clearing infectious virus from the CNS. To determine the contributions of this innate immune factor in the prevention of fatal disease, we characterized the antiviral immune response to SINV infection in
Irf7
−/−
and C57BL/6J [wild-type (WT)] mice.

Irf7
−/

−
mice had prolonged and widespread viral infection in motor neuron-rich regions of the CNS associated with more rapid and severe immunopathology in these regions. Proportions of CD8
+
T cells and inflammatory macrophages were higher in
Irf7
−/−
mice following infection, but T cells infiltrating the CNS produced fewer antiviral cytokines than in WT mice. Levels of IFN-γ and SINV-specific antibody in motor neuron-rich regions of the brain were comparable or higher than WT, indicating that IRF7 deficiency does not impair expression of these immune factors important in facilitating viral clearance. Therefore, IRF7 is required for the clearance of SINV from motor neuron-rich regions of the CNS through a mechanism that either is necessary for the neuronal response to currently identified mediators of infectious virus clearance or enables the production of additional antiviral factor(s) needed for clearance.

IMPORTANCE

Viral encephalomyelitis outcome is dependent on host responses to neuronal infection. Interferon (IFN) is an important component of the innate response, and IFN regulatory factor (IRF) 7 is an inducible transcription factor for the synthesis of IFN-α. IRF7-deficient mice develop fatal paralysis after CNS infection with Sindbis virus, while wild-type mice recover.
Irf7
−/−
mice produce low levels of IFN-α but high levels of IFN-β with induction of IFN-stimulated genes, so the reason for this difference is not understood. The current study shows that
Irf7
−/−
mice developed inflammation earlier but failed to clear virus from motor neuron-rich regions of the brainstem and spinal cord. Levels of IFN-γ and virus-specific antibody were comparable, indicating that IRF7 deficiency does not impair expression of these known viral clearance factors. Therefore, IRF7 is either necessary for the neuronal response to currently identified mediators of clearance or enables the production of additional antiviral factor(s) needed for clearance.
MicroRNA-25/93 induction by Vpu as a mechanism for counteracting MARCH1-restriction on HIV-1 infectivity in macrophages
Authors: Lodge Robert , Xu Zaikun , Eklund Mckenna , Stürzel Christina , Kirchhoff Frank , Tremblay Michel J. , Hobman Tom C. , Cohen Éric A.
Published: September 2023

The type 1 interferon-regulated E3 ubiquitin ligase MARCH1 reduces surface expression of HIV-1 envelope glycoproteins (Env) and their packaging into nascent virions, a condition that restricts viral infectivity. However, how HIV-1 counters this restriction, notably during infection of macrophages, remains unclear. Here, we show that the HIV-1 accessory protein Vpu increases the levels of microRNAs-25 and -93 to target
MARCH1
mRNA. By recruiting β-TRCP, a component of the SCF
β-TRCP
E3 ligase complex that targets phosphorylated β-catenin for degradation, Vpu increases β-catenin levels, which, in concert with TCF4/LEF, drives transcription of the
MARCH1
-targeting microRNAs. This potentiates HIV-1 infectivity as a result of increased Env incorporation into nascent virions. Pharmacological targeting of the β-catenin pathway inhibits Vpu-mediated upregulation of microRNAs-25 and -93 and restores MARCH1 restriction on HIV-1 infectivity. Overall, our findings highlight a novel mechanism by which HIV-1 counteracts MARCH1 by downregulating its expression via Vpu-mediated induction of microRNAs-25 and -93.

IMPORTANCE

In order to efficiently produce infectious viral particles, HIV must counter several restrictions exerted by host cell antiviral proteins. MARCH1 is a member of the MARCH protein family that restricts HIV infection by limiting the incorporation of viral envelope glycoproteins into nascent virions. Here, we identified two regulatory RNAs, microRNAs-25 and -93, induced by the HIV-1 accessory protein Vpu, that downregulate
MARCH1
mRNA. We also show that Vpu induces these cellular microRNAs in macrophages by hijacking the cellular β-catenin pathway. The notion that HIV-1 has evolved a mechanism to counteract MARCH1 restriction on viral infectivity underlines the importance of MARCH1 in the host antiviral response.
Complete genome sequence of
Kosakonia pseudosacchari
RX.G5M8, a putative methylotroph isolated from Hong Kong soil
Authors: Xu D. Y. , Leung K. M. , Lai G. K. K. , Griffin S. D. J.
Published: September 2023

Kosakonia pseudosacchari
RX.G5M8, a putative methylotroph, was isolated from garden soil in Hong Kong. Its complete genome, a single chromosome of 4,953,935 bp (GC content 53.91%), was established through hybrid assembly.
Draft genome sequences of four
Staphylococcus hyicus
strains, SC302, SC304, SC306, and SC310, isolated from swine from Eastern Canada
Authors: Gagné-Thivierge Cynthia , Vincent Antony T. , Paquet Valérie E. , Gauthier Marie-Lou , Denicourt Martine , Lambert Marie-Ève , Charette Steve J.
Published: September 2023

The bacterium
Staphylococcus hyicus
causes porcine exudative epidermitis in piglets, which represents both health and welfare concerns. Few genome sequences of this pathogen are published. We provide four additional ones to help future genomic analysis of
S. hyicus
. These are genomes of strains isolated from Canadian swine.
Complete genome sequence of
Edwardsiella
sp. NBRC12716 isolated in 1962 from the liver of diseased eel
Authors: Lanza Andre , Mizobata Hideaki , Yonezawa Ryo , Yoshitake Kazutoshi , Shigeharu Kinoshita , Asakawa Shuichi
Published: September 2023

We report the complete genome sequence of
Edwardsiella
sp. NBRC12716 isolated from a diseased eel in 1962. The genome consists of a single, circular chromosome 3,771,060 bp in length with 59.74% GC content and encodes 25 rRNA, 96 tRNA, and 3,182 protein-coding genes.
Emergence of KPC-134, a KPC-2 variant associated with ceftazidime-avibactam resistance in a ST11
Klebsiella pneumoniae
clinical strain
Authors: Huang Xiangning , Shen Siquan , Chang Fan , Liu Xin , Yue Jinxi , Xie Ning , Yin Lin , Hu Fupin , Xiao Daiwen
Published: September 2023

The emergence of various new
Klebsiella pneumoniae
carbapenemase (KPC) variants leading to ceftazidime-avibactam treatment failure is a new challenge in current clinical anti-infection treatment. Here, we report a ceftazidime-avibactam-resistant
K. pneumoniae
1072–2 clinical strain carrying a novel KPC variant, KPC-134, which differs from KPC-2 by both single mutation (D178A) and 8-amino acid insertions (asp-asp-asn-arg-ala-pro-asn-lys). The results of antimicrobial susceptibility testing showed that the isolate was resistant to meropenem (MIC = 4 mg/L), ceftazidime (MIC ≥ 32 mg/L), cefepime (MIC ≥128 mg/L), aztreonam (MIC ≥128 mg/L), and ceftazidime-avibactam (MIC ≥128 mg/L) but sensitive to imipenem (MIC = 0.5 mg/L), imepenem-relebactam (MIC = 0.5 mg/L), meropenem-vaborbactam (MIC = 2 mg/L), and aztreonam-avibactam (MIC = 4 mg/L). The plasmid containing
bla
KPC-134
was isolated from
K. pneumoniae
, and the
bla
KPC-134
gene was cloned into plasmid pHSG398 and transformed into an
Escherichia coli
DH5α to observe changes in antimicrobial resistance. The results indicated that the transformant was positive for
bla
KPC-134
and increased MICs of ceftazidime-avibactam, ceftazidime, cefepime, and aztreonam by 512-fold, 256-fold, 16-fold, and 4-fold, respectively, compared with the recipient. The results of third-generation sequencing showed that the
bla
KPC-134
gene was carried by a 133,789 bp IncFII-IncR plasmid, and many common resistance genes (including
bla
CTX-M-65
,
bla
TEM-1B
,
bla
SHV-12
,
rmtB
, and
catB4
) along with the IS
26
,
tnpR
,
ISkpn8
, IS
kpn6
-like, and Tn
1721
elements were identified.

IMPORTANCE

The emergence of various new KPC variants leading to ceftazidime-avibactam treatment failure is a new challenge for clinical anti-infection treatment. Here, we describe the characterization of a ceftazidime-avibactam-resistant blaKPC-134-positive
Klebsiella pneumoniae
clinical strain for the first time.
K. pneumoniae
bearing with KPC variant often mislead clinical anti-infection treatment because of their unique antimicrobial susceptibility profile and the tendency of conventional carbapenemase assays to give false negative results. Therefore, timely identification of KPC variants and effective anti-infective therapy are key to saving infected patients.
Procedural sedation programme minimising adverse events: a 3-year experience from a tertiary paediatric emergency department
Authors: Erumbala Gokul , Anzar Sabu , Deiratany Samir , Blackie Barbara , Powell Colin , Al Ansari Khalid
Published: September 2023

Introduction

A well-developed procedural sedation programme in the paediatric emergency department can minimise adverse events. We examined how adherence to current best evidence ensures safe delivery of paediatric sedation in a newly established tertiary paediatric hospital.

Methods

Our sedation service uses a robust provider training and privileging system, standardised policy and procedures and rigorous data collection all within an evidence-based clinical governance process. We examined sedation data from the first 3 years of operation.

Results

From July 2018 to May 2022, ketamine was used in 3388 of the 3405 sedations. The mean age of sedated children was 5.5 years (range 6 months to 17.8 years) and common indications were closed reduction of fractures and laceration repairs. A total of 148 (4.37%, 95% CI 3.68% to 5.06%) adverse events were documented, including 88 (2.59%, 95% CI 2.06% to 3.13%) cases of vomiting, 50 (1.48%, 95% CI 1.07% to 1.88%) cases related to airway and breathing with 40 (1.18%, 95% CI 0.82% to 1.54%) cases of oxygen desaturation, 6 (0.18%, 95% CI 0.04% to 0.32%) cases of laryngospasm, 4 (0.12%, 95% CI 0% to 0.23%) cases of apnoea.

Conclusion

This study presents a large single-centre dataset on the use of intravenous ketamine in paediatric procedural sedation. Adhering to international standards and benchmarks for provider skills and training, drug administration and monitoring facilities, with a strict clinical governance process, optimizes patient safety.
Pulmonary tumour thrombotic microangiopathy mimicking immunotherapy-associated pneumonitis
Authors: McKenzie Hayley , Scott Deborah , Bateman Adrian C , De La Pena Gomez Hugo
Published: September 2023

We present a case of pulmonary tumour thrombotic microangiopathy (PTTM) in a patient on adjuvant immunotherapy for resected triple negative breast cancer. The patient presented with deranged liver function tests and subsequently developed severe hypoxia and thrombocytopaenia, with right heart failure. The primary differential diagnosis considered was immunotherapy-associated hepatitis and pneumonitis. Despite organ support, the patient deteriorated rapidly and died of respiratory failure. As is often the case with PTTM, the diagnosis was only found at postmortem. PTTM should be considered in patients with a background of cancer (and may be more common in certain subtypes) who present with this unusual combination of clinical features. While the condition carries an extremely poor prognosis, prompter recognition for future patients may allow consideration of novel treatments.
Histologically atypical case of Gaucher disease type 1
Authors: Sabljak Jessica , Heath Oliver , Halligan Rebecca , Cheng Daryl R
Published: September 2023

This report presents a case of childhood Gaucher disease type 1, a rare inherited metabolic disorder. Although the clinical symptoms were classical, the histological findings in this case were atypical and initially led to diagnostic uncertainty. The pathognomonic histological finding on bone marrow is Gaucher cells, which are lipid-engorged phagocytes secondary to the accumulation of glucosylceramide. These cells typically demonstrate diffuse and avid iron staining using a Prussian blue iron stain. In this case, although the histiocytes seen on bone marrow were abnormal, the absence of iron staining on bone marrow led to a large range of other diagnoses being considered. In retrospect, this anomaly was likely in the setting of prolonged iron deficiency and anaemia as a result of the insidious nature of this presentation. The prognosis of type 1 Gaucher disease is favourable, with current treatments significantly improving duration and quality of life. We explore the utility of a collaborative multidisciplinary approach in addressing diagnostic uncertainty and the importance in making a diagnosis for Gaucher disease type 1 in order to provide appropriate and targeted treatment.