bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly efficient sequestration of aqueous lead on nanostructured calcite substrates
Authors: Barelli Matteo , Casado Santiago , Cassin Felix , Pimentel Carlos , Pina Carlos M , Giordano Maria Caterina , Buatier de Mongeot Francesco , Gnecco Enrico
Published: June 2023

Following defocused ion beam sputtering, large area highly corrugated and faceted nanoripples are formed on calcite (10.4) faces in a self-organized fashion. High resolution atomic force microscopy (AFM) imaging reveals that calcite ripples are defined by facets with highly kinked (11.0) and (2

1

¯

.12) terminations. In situ AFM imaging during the exposure of such modified calcite surfaces to PbCl2 aqueous solution reveals that the nanostructured calcite surface promotes the uptake of Pb. In addition, we observed the progressive smoothing of the highly reactive calcite facet terminations and the formation of Pb-bearing precipitates elongated in registry with the underlying nanopattern. By SEM–EDS analysis we quantified a remarkable 500% increase of the Pb uptake rate, up to 0.5 atomic weight % per hour, on the nanorippled calcite in comparison to its freshly cleaved (10.4) surfaces. These results suggest that nanostructurated calcite surfaces can be used for developing future systems for lead sequestration from polluted waters.
Thin and thick bubble walls. Part I. Vacuum phase transitions
Authors: Mégevand Ariel , Membiela Federico Agustín
Published: June 2023

This is the first in a series of papers where we study the dynamics
of a bubble wall beyond usual approximations, such as the assumptions
of spherical bubbles and infinitely thin walls. In this paper, we
consider a vacuum phase transition. Thus, we describe a bubble as
a configuration of a scalar field whose equation of motion depends only
on the effective potential.
The thin-wall approximation allows obtaining both
an effective equation of motion for the wall position and
a simplified equation for the field profile inside the wall.
Several different assumptions are involved in this approximation.
We discuss the conditions for the validity of each of them.
In particular, the minima of the effective potential must
have approximately the same energy, and we discuss the correct implementation of this approximation.
We consider different improvements to the basic thin-wall approximation,
such as an iterative method for finding the wall profile
and a perturbative calculation in powers of the wall width.
We calculate the leading-order corrections.
Besides, we derive an equation of motion for the wall without any assumptions about its shape.
We present a suitable method to describe arbitrarily deformed walls from the spherical shape.
We consider concrete examples and compare our approximations with numerical
solutions. In subsequent papers, we shall consider higher-order finite-width corrections,
and we shall take into account the presence of the fluid.
Study on Laser Selective Curing Additive Manufacturing of Foamed Structural Ceramics
Authors: Zhang Geng , Chen Hua , Jin Xiyuan , Zhang Fan , Zhou Rongchang
Published: June 2023

An additive manufacturing method for ceramic materials with internally formed foaming structure was proposed in this paper with the adoption of ceramic powder and sodium silicate binder to prepare sizing agent. The forming process on each layer consists of three basic processes, including spreading, freezing and laser scanning. Foaming structure arises due to the foaming effect of the frozen sodium silicate caused by laser gasification. After 3D printing, the support material in frozen state will be removed when it has been melt in water. Then finally the green ceramic parts internally filled with foaming structures will come into being. Experimental results show that the laser parameters, the content of ceramic, the scanning spacing and other factors affect the interior appearance of the green part. At the scanning speed of 100 mm·s-1, laser power of 20 W, and 0.3 mm scanning spacing, the ceramic parts are processed with a slurry with 50% solid content. The support materials in the deep fine structure can be quickly removed without mechanical damage or swelling in the water. This new process can be used to process thermal insulation ceramic parts.
Research on the Strength Check of Sub-caliber Fragment Gun Barrel
Authors: Hu Jie , Chen Hua , Ma Ying , Feng Zhiwei
Published: June 2023

In order to consider the strength of gun barrel more accurately in the design of gun barrel, a virtual prototype of fragment gun barrel is established in this paper. The finite element simulation model of the strength of gun barrel considering the axial force and temperature change is established, and the finite element simulation model of the strength of gun barrel considering the axial force, temperature change and dynamic load is established. Through numerical calculation and finite element simulation, the changes of strength of barrel under axial force, temperature and dynamic loading of bore pressure were analysed. The results show that the maximum stress of the barrel decreases when considering the axial force, and the maximum stress of the barrel increases when considering the temperature change and the dynamic loading of the chamber pressure. The axial force has little effect on the strength of the barrel, and the dynamic load has a significant effect on the strength of the barrel. Through verification, it is found that the designed fragment gun barrel is reasonable and meets the strength requirement.
Research on the Flow Field of Electrolytic Processing for Shaped Holes with Large Depth-to-diameter Ratio
Authors: Ren Rongxiang , Fan Qingming , Wang Yubian , Zhang Chuanyun , Fang Yadong
Published: June 2023

For parts with large deep-diameter ratio shaped hole features, the complex structure of the profile and large deep-diameter ratio led to poor profile machining accuracy. The shaped hole processing requires high efficiency, high precision and low cost. Therefore, it is difficult to use the traditional processing method, and the electrolysis method based on the anodic dissolution mechanism is adopted, which has no shear stress and accurate profile forming. The 3D model is established based on the part, and the cathode and tooling structure is designed. Based on COMSOL software, we designed the flow channel uniformity of electrolytic processing of shaped holes and analyzed the arrangement of cathode outlet holes in electrolytic processing, which affects the uniformity of the processed surface and flow field. The arrangement of cathode exits holes to meet the uniform distribution of electrolyte at the surface boundary and high-speed flow at the surface was obtained by simulation analysis. By analyzing the flow field of different inlets, the flow rate magnitude of the shaped boundary and surface of the surface shaped hole is positively correlated with the inlet pressure of the electrode liquid.
Electro-Mechanical Joint Simulation Technology of 3D Printing Equipment of Outer Space
Authors: Liu Haitao , Wang Lei
Published: June 2023

The outer space environment is complex, so the research and development of 3D printing equipment depends on the prototype test that is difficult to achieve on the ground, therefore, the performance of the equipment must be investigated by means of simulation. In this paper, the electro-mechanical joint simulation model of the outer space 3D printing equipment is established based on ADAMS and MATLAB/Simulink, which taking into account the overall micro-gravity environment, the nonlinear friction characteristics of each motion-axis, the inertia of each axis, and the overall frame vibration. Based on this model, the point-to-point control and the interpolation motion errors of X and Y axes with external disturbance is realized. At last the comparative control of motion error is realized, which provides a basis for the development of 3D printing equipment in outer space environment.
Thermal Error Modelling for the Parallelism Between the Gear Axis and the Z-axis of GMI
Authors: Ren Yanping , He Dongfeng , Du Hongda
Published: June 2023

Gear measuring instrument (GMI) is the mainstream equipment for gear measurement. As the measurement accuracy of gears improves and GMI is gradually used in production, thermal errors are becoming an important factor affecting the measurement accuracy of GMI. In the precision measurement of the gears, the parallelism errors between the gear axis and the Z-axis of the GMI are the major error source. This error is usually reduced by mechanical adjustment when a GMI is assembled. When the temperature of the GMI and its environment changes, the thermal deformation will lead to new parallelism errors between the gear axis and the Z-axis of the GMI, which will further cause errors in the GMI. In this paper, the effect of the parallelism thermal errors of the GMI is studied, and the parallelism thermal errors model under room temperature environment was established. First, the temperature field of the GMI and its environment and the parallelism thermal errors were measured; then, the TMP are grouped using the FCM, and the key TMP were selected by optimizing the group of the measurement points using Pearson correlation coefficient method; finally, the parallelism thermal errors were established by RBF (Radial Basis Function) neural network and tested by using the measured data. The experimental results show that the predictive accuracy of the established parallelism thermal error model can reach 60.89% in the X direction and 82.26% in the Y direction, indicating good generalization ability and robustness. The model can be used for subsequent thermal error compensation.
Super-twisting Sliding Mode Control Based on Electrostatic MEMS Micromirror Scanning
Authors: Lei Jue , Wang Chunyang , Li Fayuan , Liu Changjie
Published: June 2023

In this paper, a Super-twisting sliding-mode control method based on a nonlinear interference observer is proposed for the external perturbation of MEMS micromirrors during beam scanning. Developing a physical model of electrostatic MEMS micromirror, the Super-twisting sliding-mode control algorithm based on nonlinear interference observer is applied to the electrostatically driven MEMS scanning micromirror with side electrodes, with the demonstration on stability of the control system by Lyapunov theory. The method effectively improves the anti-disturbance performance of the system. The simulation results show that the Super-twisting sliding mode control method based on nonlinear disturbance observer can effectively enhance the disturbance inhibition of the system.
Research and Optimization of Machining Technology of Hammer Rod Subjected to Frequent Impact
Authors: Tian Chunlei , Cao Yan , Yuan Yan , Li Xiaoru , Zhang Runyan
Published: June 2023

In the oil exploration work, the hammer rod as the main component, due to the insufficient strength of the hammer rod, the hammer head falling off, the hammer body bending deformation and copper layer falling off and other problems often occur in the work, which not only affects the exploration progress but also causes huge economic losses. Aiming at the problem of insufficient strength of the hammer rod, through the analysis of the processing technology of the hammer rod and the working environment of the hammer rod, it is concluded that there are problems in the design of the hammer head, the material selection of the hammer body, and the processing technology of the copper layer. In this regard, the design of the hammer head is optimized, the depth of the inner hole of the hammer head is deepened, and the inner hole of the hammer head is changed to a taper hole; replace the 2CrMo alloy steel with higher strength as the main material of the hammer body, and add a heat treatment process after the rough turning to release the residual stress inside the hammer body; the processing process scheme for replacing the copper layer is attached to the surface of the hammer body by means of a hot-mounted copper sleeve. The improved hammer rod strength fully meets the needs of high-intensity impact work, shortens the exploration time, saves exploration costs, and makes great contributions to the exploration work.
Analysis and Research on Gap Model of Twisted Strand Steel Wire
Authors: Xue Guohua , Zhang Peng , Wang Yajuan
Published: June 2023

The breaking of steel core in the early stage of steel wire rope is a very important factor that restricts the service life of steel wire rope. By analyzing the failure of steel core broken wire, it is found that the key factor affecting the force of twisted strands is the establishment of wire gap model. Based on this, two mathematical models of the elliptic hypothesis and the non-elliptic hypothesis of the steel wire section in twisted strands are established, and two formulas for calculating the steel wire gap are derived. When the steel wire twist Angle is within a certain range, the gap of these two models is very close, but when the twist Angle exceeds a certain value, the difference between the steel wire gap becomes larger and larger. Based on this, the non-elliptic model is used to design different steel core lay lengths, and the experiment verifies that the elastic modulus of the elastic model is close to that of the steel wire rope, which reduces the tensile stress on the steel core when the steel wire rope is used, and improves the phenomenon of steel core breaking.
Finite Element Simulation and Structural Optimization of Structural Flow Sequential Field for Sequential Boost Switching Valve
Authors: Wang Lijun , Jia Jianli , Zhong Yi , Zhou Xueying , Xu Jiang , Hao Yajing
Published: June 2023

Turbocharging technology is an important part of engine technology. Under the working condition of 730 °C and 0.5 MPa, the valve plate opening and closing will bear the high pressure of the internal fluid medium, resulting in the deformation of the switching valve. In this paper, ANSYS finite element simulation software is used to establish the valve fluid domain model, and the stress field and deformation law of the valve under the valve plate opening of 0 °~ 90 °are simulated and analyzed. Based on the fluid-solid coupling theory, the deformation and stress distribution of the valve plate structure are obtained by simulation analysis. The simulation results show that the smaller the opening of the valve plate, the more disordered the flow condition. As the opening increases, the flow tends to be stable. When the opening is 30 °, the negative pressure inside the valve is the largest; combined with the fluid-solid coupling analysis, the maximum stress load on the valve plate appears at the connection between the valve plate and the long valve shaft and the short valve shaft, and the maximum pressure appears at the opening of 60 °, which is 37.144 MPa; the maximum deformation occurs at the outer edge of the valve plate. Based on the results of this simulation analysis, the corresponding multi-objective structural optimization of the valve structure is carried out to provide technical reference for the structural design of similar valves.
Study on Delay Release Time of Fuze Based on ADAMS
Authors: Zhang Yinhuan , Xiao Qinkun , Liu Xing , Zhao Wenhuang , Xue Jingyun
Published: June 2023

In order to study the arming process of electromechanical fuze security mechanism, a dynamic simulation method using ADAMS software is proposed; The simulation model of the security mechanism is established, and the existence of complex factors such as contact and collision between the rotor and adjacent components is considered in the calculation process. The time of the horizontal rotor is simulated, and the flexibility and rapidity of the rotor rotation are verified, as well as the reliability of the locking mechanism; The simulation results are compared with the statistical results of high-speed camera test, and the correctness of ADAMS software simulation results is verified.
Simulation Study of Semi-active Suspension Fuzzy Adaptive PID Control System
Authors: Wu Jianfeng , Yang Daizhe , Cao Wei , Sun Jing , Wang Yifan , Cao Zhiyang
Published: June 2023

This work develops a mathematical model of a quarter car suspension system with two degrees of freedom and suggests a fuzzy adaptive PID controller by assessing the drawbacks of conventional control methods. The three PID parameters are automatically modified by fuzzy control, and the PID parameters are adjusted in real time. The Matlab/Simulink platform is used to create the relevant simulation model. The simulation results demonstrate the superiority of the fuzzy adaptive PID control system suggested in this study by demonstrating a reduction in the Sprung Mass Acceleration by 17.85%, the Suspension Working Space by 14.42%, and the Dynamic Tyre Load by 9.48%.
Research on Aging State Detection Method of Rubber O-ring Sealing Structure
Authors: Huang Jiaqi , Qu Jinxiu , Guo Jinzhu , Shi Xiaowei , Bai Yumei , Cao Wei
Published: June 2023

The rubber seal structure is used extensively in mechanical devices, long-term use may bring major safety hazards and economic losses. In order to ensure the healthy operation of machinery and equipment, it is necessary to test the aging condition of the rubber sealing structure nondestructive online. In order to address the problem of unsteady vibration signals, a complex nonstationary signal is degraded into the sum of multiple product functions by means of global local mean decomposition, and then the energy features in these PF components are extracted, and the first three components with the largest energy eigenvalues are selected to form a sensitive feature vector set. Overall, the results of the search data show that the proposed method can efficiently extract energy features from a large set of original features, and the first three largest energy features can be selected to form a sensitive feature set, which can provide effective data information for the detection of the aging state of Rubber O-ring Sealing Structure (ROSS) in the next step.
Investigation of the supersonic flow past a wedge-shaped geometry using pressure sensitive paints technique
Authors: Hála J , Šimurda D , Lepičovský J , Luxa M
Published: June 2023

This study aims to present results of an investigation of the supersonic flow past a wedge-shaped geometry using the pressure sensitive paints technique (PSP). The wedge-shaped geometry was chosen as a canonical case for the investigation of the supersonic flow involving shock waves and strong expansion making it a convenient case to build a first practical experience with this technique, further intended for use in the investigation of linear blade cascades in high speed laboratory of the Institute of Thermomechanics of the Academy of Sciences of the Czech Republic. The tests on the wedge-shaped geometry were complemented with the numerical simulations and static pressure taps measurements. The resulting static pressure distribution obtained using the PSP on the wedge-shaped model revealed all main flow structures including positions of the separation and reattachment shocks providing a good picture of the whole flow field.
Half-scale transonic compressor rapid testing rig
Authors: Wang T , Taylor J V
Published: June 2023

High-speed compressor testing is costly due to mechanical complexity and hazardous due to the high energy involved. In the past this has limited the speed and amount of testing. In this paper a new rig architecture is presented that aims to test a scaled transonic compressor stage rapidly. It builds upon the low-speed rapid testing developments made at the Whittle Laboratory and has potential to accelerate technology development. The power input requirement is reduced by testing at half-scale and reduced Reynolds number while maintaining the Mach number. Further power saving and mechanical simplification is achieved by employing a turbo-expander architecture with no shaft-power input, only the aerodynamic losses in system must be overcome. The aerodynamic and mechanical design of the rig is presented. Safe operation and rapid access and rebuild times are critical. The test hardware is machined from solid and bladed disks and rings can be manufactured in days. Only standard instrumentation is required, although a novel control loop is employed to achieve the same accuracy in rotational speed as an electric motor driven compressor rig. Experiments up to 25% design rotational speed were conducted, and the results presented here show that the rig is controllable and inherently safe if the research compressor fails. The rig will be run to full speed in the immediate future and extension to the capability is planned with multi-stage high-speed testing in a second machine.
CFD-supported data reduction of hot-wire anemometry signals for compressible organic vapor flows
Authors: Hake L , Sundermeier S , Wiesche S aus der , Bienner A. , Gloerfelt X , Matar C , Cinnella P
Published: June 2023

For obtaining turbulent fluctuations in compressible organic vapor flows, computational fluid dynamics (CFD) analysis tools were used to support the data reduction process of hot-wire anemometry signals. It was found that CFD can help during the calibration process of actual hot-wire probes operated in the constant-temperature mode. Such an approach is beneficial for determining the dependency of the sensitivity coefficients on Reynolds and Mach numbers. Due to the small Kolmogorov scales, corrections are needed for probes with finite wire lengths. The experimental and numerical analysis considering the decay of turbulence downstream a grid indicated that the correction scheme proposed by Wyngaard leads to consistent results for compressible organic vapors. The new developments provide recommendations for obtaining turbulent quantities of compressible organic vapor flows utilizing hot-wire anemometry.
Experimental monitoring of vibrations and the problem of amplitude quantification
Authors: Schneider Alexandra P. , Paoletti Benoit , Ottavy Xavier , Brandstetter Christoph
Published: June 2023

Experimental monitoring of blade vibration in turbomachinery is typically based on blade-mounted strain gauges. Their signals are used to derive vibration amplitudes which are compared to previously determined modal scope limits, including a safety factor. According to industrial guidelines, this factor is chosen conservatively to ensure safe operation of the machine.

For the experimental campaign with the open test case fan ECL5, which is representative for modern lightweight UHBR architectures, it is planned to conduct measurements close to the stability limit. These investigations require a close approach to the limit and hence demand for accurate quantification of vibration amplitudes to ensure secure operation without exhaustive safety margins. It is required that the surveillance is possible in real time and not only in post-processing.

Historically, short-time Fourier transformations of vibration sensors are used, but the complex nature of coupled phenomena near the stability limit has an influence on the amplitude accuracy, depending on evaluation parameters. This was demonstrated in a previous study using fast response wall pressure transducers. The present study investigates the influence on blade vibration data of a modern composite material transonic fan. Different methods are compared, sensitivity to evaluation parameters is analyzed and guidelines are given for fast and robust surveillance of critical vibration modes.
Infrared thermography techniques for boundary layer state visualisation
Authors: Davis William , Atkins Nicholas R
Published: June 2023

Decarbonising power generation and aviation requires step changes in aerothermal technology. This necessitates working in large design spaces where boundary layer state and resulting loss and heat transfer characteristics are difficult to predict. Standard measurement techniques such as thin-film gauges and oil flow visualisation are intrusive and time consuming, so there is a need for rapid testing methods to diagnose boundary layer state and develop physical understanding. Infrared (IR) thermography has found wide use in aerothermal research and IR measurements of boundary layer state have been demonstrated in many experiments, however there is minimal literature on the best practices for fast and accurate measurements. IR transition measurements rely on temperature differences between laminar and turbulent regimes which are dependent on the thermal characteristics of the system. This paper shows how a 1D heat transfer analysis can be used to maximise the signal-to-noise ratio (SNR) of IR measurements. This can improve measurement quality and minimise complexity. Experimental validation is presented along with a demonstration of the value of IR in rapid testing.
Nitrogen Experiments on a Supersonic Linear Cascade For ORC Applications
Authors: Manfredi Marco , Spinelli Andrea , Persico Giacomo , Gaetani Paolo , Dossena Vinenzo
Published: June 2023

A novel experiment has been conceived at Politecnico di Milano for the study of the flow within and downstream of supersonic cascades of Organic Rankine Cycle (ORC) turbines. This paper documents the first phase of the research, focused on the preliminary tests and studies performed by operating the facility with nitrogen as working fluid, to demonstrate the technical relevance of the experiment and the validity of the measurement system in a simplified thermodynamic condition. The set of measured data includes, beside the inlet total thermodynamic state, eight static pressure values obtained via taps manufactured on the test section rear end-wall, both within the bladed and semi-bladed region of the cascade, as well as a total pressure probe to retrieve the cascade performance. A double-passage Schlieren equipment was also employed to visualize the density gradients. Experiments show an outstanding repeatability, indicate a quasi-steady cascade operation during the blow-down process for all the pressure signal considered, and demonstrate a remarkable periodicity among two consecutive channels also in off-design conditions. Experimental data were also compared with CFD simulations, resulting in an excellent agreement for the pressure data acquired both within and downstream of the cascade.
Measure of the solar flux conveyed onto a lambertian target by a novel bi-axial fresnel concentrator
Authors: Antonelli M , Caposciutti G
Published: June 2023

This paper deals with the optical analysis of a prototype of a novel concentrator, named as Bi-Axial Fresnel (BAF). This concentrator aims at reducing production and installation costs, as well as keeping as low as possible the weight and the bulk of the mirrors field, making it suitable for building small-dimensions systems, able to be placed on industrial roofs, as an example. The prototype is composed as an array of 3x3 mirrors. Its theoretical concentration is therefore 9. The experiment made use of a very basic equipment, which included a thermal flux sensor and a simple webcam, properly equipped for distinguish grey scales under quite high solar intensities. The concentrator was governed by an Arduino card, while the acquisition took place by means of a National Instruments acquisition board and Labview software. The aim of this experimental setup was the reconstruction of the solar flux on a fixed Lambertian target, based on the grey-scale maps gathered through the webcam and properly scaled accordingly to the punctual solar flux measured by the sensor. This way, the experimental apparatus was able to get an estimation of the solar power conveyed to the target.
Water-Cooled Fast-Response Wall-Static Pressure Probes for Harsh Combustor Environment Applications
Authors: Clinckemaillie Julien , Fontaneto Fabrizio , Champion-Réaud Jean-Louis , Bouty Eric , Mendes Carlos
Published: June 2023

The present paper discusses the design methodology for a water-cooled fast-response wall-static pressure probe intended for measurements in the combustion chamber of gas turbines, as well as the results from a series of tests performed with the prototype of the probe mounted in the primary zone of the combustion chamber of a turboshaft engine test rig. The first part of the present paper reviews the design methodology of a water-cooled fast-response wall static pressure probe intended for measurements of combustion noise and instabilities in gas turbine combustors, describing the optimization of measurement performance in terms of frequency bandwidth ([0 – 40kHz]) as well as the design of the cooling layout ensuring the sensor’s integrity within a harsh environment. The second part of the paper focuses on the analysis of the results obtained from trial tests performed using the probe prototype mounted in the primary zone of the combustion chamber of a helicopter engine test rig. The strengths and strong potential for further growth of the current probe design are highlighted, while its shortcomings and (short-term) solutions to these shortcomings are also discussed.
High-order field theory and a weak Euler–Lagrange–Barut equation for classical relativistic particle-field systems
Authors: FAN Peifeng , CHEN Qiang , XIAO Jianyuan , YU Zhi
Published: June 2023

In both quantum and classical field systems, conservation laws such as the conservation of energy and momentum are widely regarded as fundamental properties. A broadly accepted approach to deriving conservation laws is built using Noether’s method. However, this procedure is still unclear for relativistic particle-field systems where particles are regarded as classical world lines. In the present study, we establish a general manifestly covariant or geometric field theory for classical relativistic particle-field systems. In contrast to quantum systems, where particles are viewed as quantum fields, classical relativistic particle-field systems present specific challenges. These challenges arise from two sides. The first comes from the mass-shell constraint. To deal with the mass-shell constraint, the Euler–Lagrange–Barut (ELB) equation is used to determine the particle’s world lines in the four-dimensional (4D) Minkowski space. Besides, the infinitesimal criterion, which is a differential equation in formal field theory, is reconstructed by an integro-differential form. The other difficulty is that fields and particles depend on heterogeneous manifolds. To overcome this challenge, we propose using a weak version of the ELB equation that allows us to connect local conservation laws and continuous symmetries in classical relativistic particle-field systems. By applying a weak ELB equation to classical relativistic particle-field systems, we can systematically derive local conservation laws by examining the underlying symmetries of the system. Our proposed approach provides a new perspective on understanding conservation laws in classical relativistic particle-field systems.
A remark on the category of graded 𝐹-modules
Authors: Gray McKinley
Published: June 2023

Let

R
=
k
[
x
,
y
]

R=k[x,y]

be a polynomial ring over a field

k
k

of prime characteristic

p
p

and let

E
E

denote the injective hull of

k
k

(which is isomorphic to

H

(
x
,
y
)

2

(
R
)

H^2_{(x,y)}(R)

). We prove that

E
E

is not an injective object in the category of graded

F
F

-modules over

R
R

. This answers in the negative a question raised by Lyubeznik-Singh-Walther [J. Eur. Math. Soc. (JEMS) 18 (2016), pp. 2545- 2578].
The equivariant Ehrhart theory of polytopes with order-two symmetries
Authors: Clarke Oliver , Higashitani Akihiro , Kölbl Max
Published: June 2023

We study the equivariant Ehrhart theory of families of polytopes that are invariant under a non-trivial action of the group with order two. We study families of polytopes whose equivariant

H
∗

H^\ast

-polynomial both succeed and fail to be effective, in particular, the symmetric edge polytopes of cycle graphs and the rational cross-polytope. The latter provides a counterexample to the effectiveness conjecture if the requirement that the vertices of the polytope have integral coordinates is loosened to allow rational coordinates. Moreover, we exhibit such a counterexample whose Ehrhart function has period one and coincides with the Ehrhart function of a lattice polytope.
Methylocystis iwaonis sp. nov., a type II methane-oxidizing bacterium from surface soil of a rice paddy field in Japan, and emended description of the genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993
Authors: Kaise Hirotaka , Sawadogo Joseph Benewindé , Alam Mohammad Saiful , Ueno Chihoko , Dianou Dayéri , Shinjo Rina , Asakawa Susumu
Published: June 2023

A novel methane-oxidizing bacterial strain SS37A-ReT was isolated from surface soil of a rice paddy field in Japan. Cells were Gram-stain-negative, motile rods with single polar flagellum and type II intracytoplasmic membrane arrangement. The strain grew on methane or methanol as the sole carbon and energy source. It grew at 15–37 °C (optimum 25–30 °C), pH 6.0–9.0 (optimum 7.0–8.0) and with 0–0.1 % (w/w) NaCl (no growth at 0.5 % or above). Cells formed cysts, but not exospores. The results of sequence analysis of the 16S rRNA gene indicated that SS37A-ReT represented a member of the family

Methylocystaceae

, with the highest similarity (98.9 %) to Methylocystis parva corrig. OBBPT. Phylogenetic analysis of pmoA and mxaF genes and core genes in the genome indicated that the strain was closely related to the members of the genus

Methylocystis

, while the analysis of the mmoX gene indicated the close relationships with the genus

Methylosinus

. The values of genome relatedness between SS37A-ReT and species of the genera

Methylocystis

and

Methylosinus

were 78.6–82.5% and 21.7–24.9 % estimated by the average nucleotide identity and digital DNA–DNA hybridisation, respectively, showing the highest values with

Methylocystis echinoides

LMG 27198T. The DNA G+C content was 63.2 mol% (genome). The major quinone and fatty acids were Q-8 and, C18 : 1 (C18 : 1ω8t and C18 : 1ω8c) and C18 : 2, respectively. On the basis of the phenotypic and phylogenetic features, the strain represents a novel species of the genus

Methylocystis

, for which the name Methylocystis iwaonis sp. nov. is proposed. The type strain is SS37A-ReT (=JCM 34278T =NBRC 114996T=KCTC 82710T).
Cross-modal sensory boosting to improve high-frequency hearing loss
Authors: Kohler Izzy , Perrotta Michael V. , Ferreira Tiago , Eagleman David M.
Published: June 2023

High frequency hearing loss is one of the most common problems in the aging population and with those who have a history of exposure to loud noises. To address high-frequency hearing loss, we developed a multi-motor wristband that uses machine learning to listen for specific high frequency phonemes. The wristband vibrates in spatially unique locations to represent which phoneme was present, in real time. We recruited 16 participants with high frequency hearing loss and asked them to wear the wristband for six weeks. Their degree of disability associated with hearing loss was measured weekly using the Abbreviated Profile of Hearing Aid Benefit (APHAB). Our findings show that vibrotactile sensory substitution delivered by a wristband that produces spatially distinguishable vibrations in correspondence with high frequency phonemes helps individuals with high frequency hearing loss improve their understanding of verbal communication. We find that vibrotactile feedback provides benefits whether or not a person wears hearing aids, albeit in slightly different ways. Finally, our results also demonstrate that individuals with the greatest difficulty understanding speech prior to the study experience the greatest amount of benefit from vibrotactile feedback.
Using Polygenic Scores for Circadian Rhythm to predict Wellbeing, Depressive Symptoms, Chronotype, and Health
Authors: Landvreugd A. , Pool R. , Nivard M. , Bartels M.
Published: June 2023

The association between the circadian rhythm and diseases has been well-established, while the association with mental health is less explored. Given the heritable nature of the circadian rhythm, this study aimed to investigate the relationship between genes underlying the circadian rhythm and mental health outcomes, as well as a possible gene-environment correlation for circadian rhythm. In a sample from the Netherlands Twin Register (N= 14,021), polygenic scores (PGSs) were calculated for two circadian rhythm measures: Morningess and Relative Amplitude. The PGSs were used to predict mental health outcomes such as subjective happiness, quality of life, and depressive symptoms In addition, we performed the same prediction analysis in a within-family design in a subset of dizygotic twins. The PGS for Morningness significantly predicted Morningness (R2= 1.55%,) and Depressive Symptoms (R2= 0.22%,). The PGS for Relative Amplitude significantly predicted General Health (R2= 0.12%,) and Depressive Symptoms (R2= 0.20%,). Item analysis of the depressive symptoms showed that 4/14 items were significantly associated with the PGSs. The within-family results hinted at a gene-environment correlation for Morningness. Overall, the results showed that people with a genetic predisposition of being a morning person or a high relative amplitude are likely to have fewer depressive symptoms. Contrarily to our hypotheses, the four associated depressive symptoms described symptoms related to decision-making, energy, and feeling worthless, rather than sleep. Our findings plead for a substantial role for the circadian rhythm in depression research, and to further explore the gene-environment correlation in the circadian rhythm.
Rapid and Multiplexed Nucleic Acid Detection using Programmable Aptamer-Based RNA Switches
Authors: Yan Zhaoqing , Tang Anli A. , Eshed Amit , Ticktin Zackary M. , Chaudhary Soma , Ma Duo , McCutcheon Griffin , Li Yudan , Wu Kaiyue , Saha Sanchari , Alcantar-Fernandez Jonathan , Moreno-Camacho Jose L. , Campos-Romero Abraham , Collins James J. , Yin Peng , Green Alexander A.
Published: June 2023

Rapid, simple, and low-cost diagnostic technologies are crucial tools for combatting infectious disease. Here, we describe a class of aptamer-based RNA switches called aptaswitches that recognize specific target nucleic acid molecules and respond by initiating folding of a reporter aptamer. Aptaswitches can detect virtually any sequence and provide a fast and intense fluorescent readout, generating signals in as little as 5 minutes and enabling detection by eye with minimal equipment. We demonstrate that aptaswitches can be used to regulate folding of six different fluorescent aptamer/fluorogen pairs, providing a general means of controlling aptamer activity and an array of different reporter colors for multiplexing. By coupling isothermal amplification reactions with aptaswitches, we reach sensitivities down to 1 RNA copy/µL in one-pot reactions. Application of multiplexed one-pot reactions against RNA extracted from clinical saliva samples yields an overall accuracy of 96.67% for detection of SARS-CoV-2 in 30 minutes. Aptaswitches are thus versatile tools for nucleic acid detection that can be readily integrated into rapid diagnostic assays.
A Multi-Ancestry Polygenic Risk Score for Coronary Heart Disease Based on an Ancestrally Diverse Genome-Wide Association Study and Population-Specific Optimization
Authors: Smith Johanna L. , Tcheandjieu Catherine , Dikilitas Ozan , Iyer Kruthika , Miyazawa Kazuo , Hilliard Austin , Lynch Julie , Rotter Jerome I. , Chen Yii-Der Ida , Sheu Wayne Huey-Herng , Chang Kyong-Mi , Kanoni Stavroula , Tsao Phil , Ito Kaoru , Kosel Matthew , Clarke Shoa L. , Schaid Daniel J. , Assimes Themistocles L. , Kullo Iftikhar J.
Published: June 2023

Background

Predictive performance of polygenic risk scores (PRS) varies across populations. To facilitate equitable clinical use, we developed PRS for coronary heart disease (PRSCHD) for 5 genetic ancestry groups.

Methods

We derived ancestry-specific and multi-ancestry PRSCHDbased on pruning and thresholding (PRSP+T) and continuous shrinkage priors (PRSCSx) applied on summary statistics from the largest multi-ancestry genome-wide meta-analysis for CHD to date, including 1.1 million participants from 5 continental populations. Following training and optimization of PRSCHDin the Million Veteran Program, we evaluated predictive performance of the best performing PRSCHDin 176,988 individuals across 9 cohorts of diverse genetic ancestry.

Results

Multi-ancestry PRSP+Toutperformed ancestry specific PRSP+Tacross a range of tuning values. In training stage, for all ancestry groups, PRSCSxperformed beter than PRSP+Tand multi-ancestry PRS outperformed ancestry-specific PRS. In independent validation cohorts, the selected multi-ancestry PRSP+Tdemonstrated the strongest association with CHD in individuals of South Asian (SAS) and European (EUR) ancestry (OR per 1SD[95% CI]; 2.75[2.41-3.14], 1.65[1.59-1.72]), followed by East Asian (EAS) (1.56[1.50-1.61]), Hispanic/Latino (HIS) (1.38[1.24-1.54]), and weakest in African (AFR) ancestry (1.16[1.11-1.21]). The selected multi-ancestry PRSCSxshowed stronger association with CHD in comparison within each ancestry group where the association was strongest in SAS (2.67[2.38-3.00]) and EUR (1.65[1.59-1.71]), progressively decreasing in EAS (1.59[1.54-1.64]), HIS (1.51[1.35-1.69]), and lowest in AFR (1.20[1.15-1.26]).

Conclusions

Utilizing diverse summary statistics from a large multi-ancestry genome-wide meta-analysis led to improved performance of PRSCHDin most ancestry groups compared to single-ancestry methods. Improvement of predictive performance was limited, specifically in AFR and HIS, despite use of one of the largest and most diverse set of training and validation cohorts to date. This highlights the need for larger GWAS datasets of AFR and HIS individuals to enhance performance of PRSCHD.
Graph representations of iEEG data for seizure detection with graph neural networks
Authors: Díaz-Montiel Alan A. , Lankarany Milad
Published: June 2023

Epilepsy is a neurological disorder that affects over 50 million individuals worldwide. Today, the gold-standard treatment for those who are drug resistant, meaning that symptoms cannot be controlled with medication, is to surgically remove the seizure onset zone (SOZ), the area of the brain believed to cause seizures: the main symptom of epilepsy. Unfortunately, around 50% of drug resistant patients are not resective candidates, which can be attributed in part to poor SOZ localization. SOZ localization is a complex and lengthy procedure, requiring visual inspection and manual processing by human experts that first need to localize and isolate seizure events. The intracranial electroencephalography (iEEG) is a tool that records electrophysiological activity of the inner brain at different regions and depths, and provides critical information on the SOZ. However, iEEG data processing methodologies are not standardized, and practice and resources vary across hospitals and clinics. To assist human experts with systematic processing of iEEG data, we propose a data processing pipeline that generates graph representations of iEEG data. We evaluate 9 different graph representations of publicly available iEEG data from 25 patients with epilepsy with a graph neural network model trained to detect seizures. Our results suggest that graph representations of iEEG data that leverage electrode and functional connectivity features are powerful data structures to analyze and interpret iEEG data in the context of epilepsy. We anticipate that our data pipeline that provides a systematic processing of neural data with graphs can integrate other data modalities like neuroimaging data. Moreover, methods used in the data pipeline have potentials to apply to other neurological disorders such as Parkinson’s disease or major depression disorder.
Forecasting fish recruitment using machine learning methods: A case study of arabesque greenling
Authors: Okamura Hiroshi , Morita Shoko , Kuroda Hiroshi
Published: June 2023

Fish recruitment prediction is a central topic in fisheries science. We use a machine learning method for predicting the recruitment of Arabesque greenling in Hokkaido, Japan. Biological, fisheries-related, and environmental factors were included in the predictive models as feature variables. A gradient boosting model (GBM) showed better predictive performance compared with a linear regression model (LRM) and a random forest model (RFM) in terms of relative bias and relative root mean square error for recruitment prediction in the last 5 years. The most influential feature for GBM was spawning stock biomass in the last year, followed by the fishing rate for older fish. The sea surface temperature (SST) was a very weak predictor in the GBM but was the most influential feature in the LRM. The difference among models suggests the importance of nonlinearity and variable interactions. Machine learning methods will greatly contribute to fish recruitment forecast and thereby sustainable fisheries management.
A novel deep proteomic approach in human skeletal muscle unveils distinct molecular signatures affected by aging and resistance training
Authors: Roberts Michael D. , Ruple Bradley A. , Godwin Joshua S. , McIntosh Mason C. , Chen Shao-Yung , Kontos Nicholas J. , Agyin-Birikorang Anthony , Michel J. Max , Plotkin Daniel L. , Mattingly Madison L. , Mobley C. Brooks , Ziegenfuss Tim N. , Fruge Andrew D. , Kavazis Andreas N.
Published: June 2023

We examined the myofibrillar (MyoF) and non-myofibrillar (non-MyoF) proteomic profiles of the vastus lateralis (VL) muscle of younger (Y, 22±2 years old; n=5) and middle-aged participants (MA, 56±8 years old; n=6), and MA following eight weeks of knee extensor resistance training (RT, 2d/week). Shotgun/bottom-up proteomics in skeletal muscle typically yields wide protein abundance ranges that mask lowly expressed proteins. Thus, we adopted a novel approach whereby the MyoF and non-MyoF fractions were separately subjected to protein corona nanoparticle complex formation prior to digestion and Liquid Chromatography Mass Spectrometry (LC-MS) analysis. A total of 10,866 proteins (4,421 MyoF and 6,445 non-MyoF) were identified. Across all participants, the number of non-MyoF proteins detected averaged to be 5,645±266 (range: 4,888–5,987) and the number of MyoF proteins detected averaged to be 2,611±326 (range: 1,944–3,101). Differences in the non-MyoF (8.4%) and MyoF (2.5%) proteome were evident between age cohorts. Further, most of these age-related non-MyoF proteins (447/543) were more enriched in MA versus Y. Several biological processes in the non-MyoF fraction were predicted to be operative in MA versus Y including (but not limited to) increased cellular stress, mRNA splicing, translation elongation, and ubiquitin-mediated proteolysis. Non-MyoF proteins associated with splicing and proteostasis were further interrogated, and in agreement with bioinformatics, alternative protein variants, spliceosome-associated proteins (snRNPs), and proteolysis-related targets were more abundant in MA versus Y. RT in MA non-significantly increased VL muscle cross-sectional area (+6.5%, p=0.066) and significantly increased knee extensor strength (+8.7%, p=0.048). However, RT modestly altered the MyoF (∼0.3%, 11 upregulated and two downregulated proteins) and non-MyoF proteomes (∼1.0%, 56 upregulated and eight downregulated proteins, p<0.01). Further, RT did not affect predicted biological processes in either fraction. Although participant numbers were limited, these preliminary results using a novel deep proteomic approach in skeletal muscle suggest that aging and RT predominantly affects protein abundances in the non-contractile protein pool. However, the marginal proteome adaptations occurring with RT suggest either: a) this may be an aging-associated phenomenon, b) more rigorous RT may stimulate more robust effects, or c) RT, regardless of age, subtly affects skeletal muscle protein abundances in the basal state.