bluuebunny/crossref_metadata_2025 huggingface dataset:
Instability of the cosmological DBI-Galileon in the non-relativistic limit
Authors: Leloup C , Heitz L , Neveu J
Published: September 2023

The DBI-Galileon model is a scalar-tensor theory of gravity which is defined as the most general theory of the dynamics of a 4D brane embedded in a 5D bulk. It is of particular interest as it introduces only a few free parameters, all with a clear physical meaning, such as the brane tension which is related to the cosmological constant. From the tight constraints on the gravitational waves speed, we are naturally led to consider the non-relativistic limit of the model where the kinetic energy of the brane is small compared to its tension, that we study in the context of late-time cosmology. We show that the Dirac–Born–Infeld-Galileon in the non-relativistic limit is an expansion around General Relativity which can be expressed as a shift-symmetric Horndeski theory. We develop the description of this theory at the background and perturbation level. However, by studying the scalar and tensor perturbations around a flat FLRW background, we find that they contain a ghost degree of freedom leading to a fatal instability of the vacuum for every combination of the free parameters. In order to avoid it in the more general cases of shift-symmetric Horndeski theories, we emphasize which of the Horndeski terms are in competition to produce this instability.
A fast analytical dose calculation approach for MRI-guided proton therapy
Authors: Duetschler Alisha , Winterhalter Carla , Meier Gabriel , Safai Sairos , Weber Damien C , Lomax Antony J , Zhang Ye
Published: September 2023

Objective. Magnetic resonance (MR) is an innovative technology for online image guidance in conventional radiotherapy and is also starting to be considered for proton therapy as well. For MR-guided therapy, particularly for online plan adaptations, fast dose calculation is essential. Monte Carlo (MC) simulations, however, which are considered the gold standard for proton dose calculations, are very time-consuming. To address the need for an efficient dose calculation approach for MRI-guided proton therapy, we have developed a fast GPU-based modification of an analytical dose calculation algorithm incorporating beam deflections caused by magnetic fields. Approach. Proton beams (70–229 MeV) in orthogonal magnetic fields (0.5/1.5 T) were simulated using TOPAS-MC and central beam trajectories were extracted to generate look-up tables (LUTs) of incremental rotation angles as a function of water-equivalent depth. Beam trajectories are then reconstructed using these LUTs for the modified ray casting dose calculation. The algorithm was validated against MC in water, different materials and for four example patient cases, whereby it has also been fully incorporated into a treatment plan optimisation regime. Main results. Excellent agreement between analytical and MC dose distributions could be observed with sub-millimetre range deviations and differences in lateral shifts <2 mm even for high densities (1000 HU). 2%/2 mm gamma pass rates were comparable to the 0 T scenario and above 94.5% apart for the lung case. Further, comparable treatment plan quality could be achieved regardless of magnetic field strength. Significance. A new method for accurate and fast proton dose calculation in magnetic fields has been developed and successfully implemented for treatment plan optimisation.
DE-UFormer: U-shaped dual encoder architectures for brain tumor segmentation
Authors: Dong Yan , Wang Ting , Ma Chiyuan , Li Zhenxing , Chellali Ryad
Published: September 2023

Objective. In brain tumor segmentation tasks, the convolutional neural network (CNN) or transformer is usually acted as the encoder since the encoder is necessary to be used. On one hand, the convolution operation of CNN has advantages of extracting local information although its performance of obtaining global expressions is bad. On the other hand, the attention mechanism of the transformer is good at establishing remote dependencies while it is lacking in the ability to extract high-precision local information. Either high precision local information or global contextual information is crucial in brain tumor segmentation tasks. The aim of this paper is to propose a brain tumor segmentation model that can simultaneously extract and fuse high-precision local and global contextual information. Approach. We propose a network model DE-Uformer with dual encoders to obtain local features and global representations using both CNN encoder and Transformer encoder. On the basis of this, we further propose the nested encoder-aware feature fusion (NEaFF) module for effective deep fusion of the information under each dimension. It may establishe remote dependencies of features under a single encoder via the spatial attention Transformer. Meanwhile ,it also investigates how features extracted from two encoders are related with the cross-encoder attention transformer. Main results. The proposed algorithm segmentation have been performed on BraTS2020 dataset and private meningioma dataset. Results show that it is significantly better than current state-of-the-art brain tumor segmentation methods. Significance. The method proposed in this paper greatly improves the accuracy of brain tumor segmentation. This advancement helps healthcare professionals perform a more comprehensive analysis and assessment of brain tumors, thereby improving diagnostic accuracy and reliability. This fully automated brain model segmentation model with high accuracy is of great significance for critical decisions made by physicians in selecting treatment strategies and preoperative planning.
Quantum droplets in one-dimensional Bose-Bose mixtures: beyond the Lee-Huang-Yang description
Authors: Boudjemâa Abdelâali , Abbas Karima
Published: September 2023

The static and dynamic properties of self-bound quantum droplets in a one-dimensional Bose-Bose mixture are discussed in the spirit of the Hartree–Fock-Bogoliubov theory. This latter enables us to provide beyond the Lee-Huang-Yang (LHY) quantum corrections to the equation of state at both zero and finite temperatures. In the uniform case our results for the ground-state energy and the critical temperature are confirmed through comparison with Quantum Monte-Carlo simulation and with available theoretical results. The density profiles are supported by numerical simulations of the generalized Gross-Pitaevskii equation which selfconsistently includes higher-order terms originating from the normal and anomalous fluctuations under the local density approximation. We show that the density exhibits a dip near its center in the flat-top plateau region for large interspecies interactions. We exemplify the impact of the beyond LHY corrections on the spatiotemporal evolution of the self-bound droplet in the presence of excitation induced by periodic density modulation. It is found that higher-order corrections may lead to the formation of a train of small droplets. We then extend our study for the case of inhomogeneous droplets in quasi one-dimensional Bose mixtures.
Influence of the Spatial Position of the Semi-open Impeller on the Internal Flow Field in Centrifugal Fans
Authors: Zhao Xintong , Guan Jianhui
Published: September 2023

This paper takes as its background the study of centrifugal fans in powered air-purifying respirators. To improve the efficiency of the centrifugal fan and the uniformity of the internal flow field, a steady-state simulation based on the realizable k-ε turbulence model, using the “frozen rotor method”, was carried out to analyze the effect of the spatial position of the impeller in the centrifugal fan on the internal flow field by matching the impeller to the worm gear. The results show that varying the eccentric angle, eccentric distance, and longitudinal depth of the semi-open impeller in the volute affects the internal flow field of the centrifugal fan to varying degrees. The concentric arrangement was not found to be optimal, and when the impeller rotates slightly further away from the worm tongue, the flow field inside the centrifugal fan is more uniform and the phenomena such as “wake-jet” and boundary layer separation are significantly reduced. In addition, it was found that the pressure distribution at the inlet is approximately the same as the pressure distribution in the flow field.
Preparation of CuO/g-C3N4 and its effect on the removal of phenol
Authors: Chao Lei , Chen Shiyuan , Sun Fang , Mo Xiaoyun
Published: September 2023

In this paper, CuO/g-C3N4 catalyst was prepared by one-step hydrothermal calcination, characterized, and analyzed by scanning electron microscope, X-ray diffraction, and X-ray photoelectron technology to test the activation effect and regeneration properties, and to investigate the effect of photocatalytic removal of phenol from the water after activation of sulfate with this material. A xenon lamp was used to simulate the visible light source, and the self-prepared phenol wastewater was used as the treated water sample to observe the treatment effect of the test under different test systems. The results show that the morphology of CuO/g-C3N4 and various energy peaks meet the requirements and have good photoactivation characteristics. The stability and recyclability of the catalyst were good, and the treatment of phenol reached 76 % after five tests. The phenol removal rate was 86.71 % at a reaction temperature of 40 °C, a catalyst dosage of 1 g/L, a persulfate concentration of 4 mM, and pH=5. In conclusion, CuO/g-C3N4 has a broad application prospect as a catalyst.
Lightweight Optimization of Garbage Collection Truck Manipulator Based on Parametric Modelling
Authors: Luo Li , Li Xucheng , Yuan Mingxin
Published: September 2023

In order to improve the performance of garbage collection truck manipulators, a three-dimensional model of the garbage collection truck manipulator is established based on SolidWorks. The dynamic analysis of the garbage collection truck manipulator model is carried out using the ADAMS software according to its movement in different working conditions, obtaining the displacement, force, and speed curves. The model is identical to garbage collection truck manipulators used in real situations. The static characteristics of the garbage collection truck manipulator model are analyzed in HyperWorks, which provides the conditions for the subsequent optimization. Finally, based on parametric modeling, taking the volume minimum as the goa, keeping the deformation and stress to meet the requirements for use as constraints, a genetic algorithm is used to optimize the weight of the manipulator. The optimization results show that the mass of the manipulator can be reduced by 17 kg (16.73%) while the strength meets the requirements.
Design and Characteristics of Shape Memory Alloy Bidirectional Torsional Actuator
Authors: Shen Chuanliang , Zhan Jincheng , Deng Yifei , Gao Yaohui
Published: September 2023

To overcome the problems of the low power/weight ratio of traditional servo motors, complex transmission systems, and large space occupied by hydraulic drive systems, this paper designs a bidirectional torsional actuator using the shape memory effect of Ti-Ni shape memory alloy (SMA) wire, which aims to realize the folding and unfolding of the wings of flying cars. The model of the designed actuator was established and the theoretical calculation was analyzed, based on which the experimental verification was carried out. It is found that when the heating current is 1.6 A, the mechanism can take into account the economy under the premise of meeting a certain folding speed. When the pre-stretching amount of SMA wire is 3%, the residual strain corresponding to the wire is small, about 0.577%, and it can provide driving torque and torsion angle to meet the design requirements of the actuator. This verifies the feasibility of the actuator and obtains the driving characteristics of the actuator. Finally, the shortcomings and improvement measures of the actuator are analyzed briefly.
Experimental study of the double-layer cylindrical shell under uniform axial pressure
Authors: Nie Luqing , Wang Lihui
Published: September 2023

In this paper, the buckling performance of the double-layer cylindrical structure with different layers of materials under uniform axial pressure is studied. Three identical double-layer and single-layer cylindrical thin shells are fabricated, measured, and tested respectively. The results indicate that the average ultimate strength of the double-layer cylinder is about 1.91 times that of the single-layer cylinder.
Oxide Inclusions in Aluminum-deoxidized Ultra-low CarbonSteel
Authors: Yang Chengwei , Liu Yi
Published: September 2023

RH (Ruhrstahl-Heraeus) degassing process was confirmed to be an effective method for making the steel cleaner by comparing the samples before and after RH degassing, mainly on the area of the total inclusion, the total number of inclusions, the mean area of inclusions, and inclusion size distribution. Four main types of inclusions including alumina and titanium oxides, and Al-Ti-O complex oxides were studied by analyzing their formation mechanisms, compositions, and morphology using SEM (scanning electron microscope) and EDS (energy-dispersive X-ray spectroscopy). Thermodynamic analysis through kinetic simulations of the different stages of RH degassing was conducted by the FactSageTM software package. Based on the equilibrium amount of oxides in the liquid steel, the effects of system temperature, oxygen contents, and alloy additions on the formation of inclusions and nozzle clogging were discussed to improve the steel’s cleanliness.
Tests and dynamic simulation analysis of an automatic instrument
Authors: Chen Qiangqiang , He Lei
Published: September 2023

To better study the dynamic characteristics of an automatic instrument and establish a realistic simulation model of automatic instruments, this paper has carried out movement tests of crucial parts under fixed conditions and recoil tests and collected the speed-time and recoil-time curves. Based on ADAMS software, the virtual prototype model of the key parts of the instrument is established, and the dynamic simulation is carried out. The different simulation results are separately compared with the experimental data, which verifies the accuracy of the recoil simulation model and provides a reference for the optimal design and improvement of the automatic instrument.
The synthesis of high-strength monolithic Al2O3-SiO2 aerogels through increased solid content and high-temperature calcination
Authors: Li Guoqi , Hu Li , Zhang Kai , Hou Sifan , Fan Jinpeng
Published: September 2023

High-strength Al2O3-SiO2 aerogels were synthesized by simultaneously increasing the solid content and high-temperature calcination. The effects of solid content and high-temperature calcination on mechanical properties, thermal conductivity, and microstructure of Al2O3-SiO2 aerogels were studied. The increase in solid content can improve the mechanical properties of aerogels. High-temperature calcination can further improve mechanical properties and reduce thermal conductivity. Finally, we fabricated a high-strength monolithic Al2O3-SiO2 aerogel with a high Young’s modulus of 127.45 MPa, room temperature thermal conductivity of 29.15 mW·m−1·K−1, and density of 252 mg·cm−3. This work is significant to the adhibition of Al2O3-SiO2 aerogels as high-strength thermal insulation materials.
Optimal Trajectory Planning Control for Quadruped Robot
Authors: Ren Dongyi , Cui Yushu
Published: September 2023

The posture information of the quadruped robot changes in real-time during its movement, and the trajectory planning method in view of trunk posture feedback is proposed. The kinematics equations of the mobile robot are built. The transformation matrix between the robot trunk posture and the foot-leg joint displacement is obtained. The feedback information of the body posture is integrated when planning motion trajectory. The motion trajectory of the robot according to the feedback information of the trunk posture is planned. The trajectories of the robot in the forward, lateral, and vertical directions are planned, respectively. The effectiveness and rationality of the optimal trajectory planning strategy are tested by the quadruped robot simulation platform.
Construction Method of Loop-Watt Mechanism Based on Watt Six-bars Units
Authors: Sun Xuemin , Yu Biao , Yu Zhiguo
Published: September 2023

In this paper, three Watt six-bar units are proposed to construct a loop connection mechanism (Loop-Watt mechanism) with a single degree of freedom (DOF) through the loop connection of rotating joints, and the constructed mechanism can complete the turnover motion. First of all, by analyzing the characteristics of the Watt six-bars unit and the theme idea of loop connection, the concrete method of loop connection is proposed, and the construction method of the Loop-Watt mechanism (LW-M) is obtained. Secondly, the DOF, motion forms, and motion characteristics of the Loop-Watt mechanism are analyzed, and its motion modes are obtained. Finally, the correctness of the analysis results is verified by establishing a 3D model in SolidWorks software. The Loop-Watt mechanism constructed in this paper is expected to have important application prospects in sealing mechanisms and large deployable mechanisms.
Research on automatic assembly technology of complex curved composite components
Authors: Zhang Tianzhu , Gao Aijuan , Wang Qi , Zhang Pin
Published: September 2023

Sophisticated composite materials have a range of outstanding broad merits such as high particular strength, high specific stiffness, powerful designability, excellent tiredness resistance, excellent durability, are widely used in transportation, medical, electronics and other area. The assembly process of the composite surface components has large assembly stress, which affects the assembly accuracy. At the same time, the manual assembly cycle is elongated, the efficiency is low, and the quality stability is impoverished, which constraints the assembly mass and assembly power of the complex curved composite components. To improve the assembly power and carry out automatic assembly, this paper designs the automatic assembly technology scheme of the complex curved composite components, designs the automatic assembly scheme verification device, and conducts the automatic assembly test to verify the feasibility of the scheme.
Study on Failure Mode of Cast Aluminum Alloy in Marine Environment
Authors: Li Xiangyu , Zhao Yapeng , Wang Yong
Published: September 2023

Aluminum alloy is an important metal material in the industrial field. With good mechanical properties, the ZL205A high-strength casting aluminum alloy has been widely used in aviation, aerospace, and other fields. In this paper, the erosion phenomenon of the ZL205A cast aluminum alloy on a certain type of marine equipment is described, and the failure mode of the ZL205A cast aluminum alloy in the marine environment is analyzed by simulation calculation and experimental verification. It provides technical support for the antierosion treatment and structural optimization of subsequent casting aluminum alloy equipment.
Analysis of cable eccentric diameter measurement based on the production line
Authors: Li Hongda , Jia Wentao
Published: September 2023

In order to meet the requirements of real-time monitoring and timely adjustment of cable diameter, a laser caliper is installed on the cable production line. Based on the laser diffraction measurement technology, the related laser diameter measuring instrument was developed. This equipment adopts a CCD array sensor and two mutually perpendicular pulse laser light sources, with a single exposure of only 0.1μs. It can identify the measuring objects with instantaneous changes, such as jittery workpieces, and obtain the outer diameter of the measured object through complex algorithm processing and relevant data calculation. The equipment is designed by relying on the laser diffraction measurement method and electromagnetic induction technology and using the CCD laser diffraction principle. In addition, the error can also be introduced into the linear array CCD image collector. TCD1703C is used for the linear array CCD, and the size length of each pixel is 7μm. If the measurement result is not processed by edge subdivision, the maximum measurement accuracy can only reach 7μm resolution.
Development and Research on Localization of Coal Machine Reducer Based on Reverse Engineering
Authors: Liu Xiaoxia
Published: September 2023

With the trend of localization of imported coal machine reducers being imperative, the traditional reducer development method has the problems of a high failure rate in the design stage, a long development cycle, and high manufacturing costs. Based on reverse engineering, this paper discusses the process of localization and development of imported coal machine reducers and focuses on the five steps from the reducer design stage. The determination of the boundary parameters of the reducer, the acquisition of the surface data and performance data of the reducer parts, the three-dimensional modeling, the virtual assembly, and the interference inspection are analyzed. This paper summarizes the key technologies of the localization development of the reducer and forms an effective method for the localization development of the imported coal machine reducer. Finally, the feasibility and effectiveness of the localization development method of the reducer are verified by an example.
Harnessing of the low energy wind potential
Authors: Iliev R , Tsalov Ts
Published: September 2023

This paper analyzes the wind energy parameters for different areas with low wind energy potential using the data from the global online wind map. The performance characteristics of different types of wind turbines are reviewed. The generated theoretical electric energy within one year for 9 types of wind turbines is presented. Suitable wind turbines for harnessing low wind potential, that can cover the electrical needs of one household are proposed.
A possibility of harnessing the heat discarded into the environment using thermoelectric generators.
Authors: Danca Paul Alexandru , Babutanu Corina , Bunea Florentina , Dogeanu Angel
Published: September 2023

Energy demand from the last decade combined with the requirement of lowering pollutant emissions, created the need to harvest energy which normally is not used. Some of the harvesting elements are thermoelectric generators which have become used nowadays. The purpose of this study is to use thermoelectric generators, to capitalize heat release in nature by an air conditioning system. An experimental study was concluded and the mean temperature difference Δt between the hot and cold source was 70°C. According to a chosen thermoelectric module, the energy produced at this Δt is around 1.85W.
Research of the energy parameters of the most demanded wood biomass pellets on Bulgarian market
Authors: Murzova M , Zlateva P
Published: September 2023

The following research focuses on exploring the energy parameters of the most demanded wood biomass pellets on the Bulgarian market. To assess the accuracy and reliability of the information provided on the packaging of wood pellets, a comparative analysis was conducted. The initial step involved conducting experimental tests to determine the energy characteristics of the most demanded brands of waste wood raw materials, as reported by the surveyed customers. These parameters included diameter, calorific value, ash content, and moisture content. By comparing the data obtained from the experiments with the information stated on the packaging, it was observed that all analysed parameters met the requirements outlined in the ENplus quality certificate. Additionally, the results confirmed that the wood pellets belonged to class A1, indicating their high quality and adherence to the specified standards.
Uncertainty Assessment in the Prediction of Selected Fission Products in the Case of a Postulated Severe Accident Scenario at VVER-1000
Authors: Groudev P. , Petrova P. , Vryashkova P.
Published: September 2023

The aim of the paper is to present the results and insights gained from the analysis of the postulated severe accident scenario for the Nuclear Power Plant (NPP) equipped with a VVER-1000, focusing on the uncertainty assessment in the prediction of selected Fission Products (FPs). To this end, the simulation of the Large Break Loss of Coolant Accident (LB LOCA) along with a Station Blackout (SBO) scenario was carried out. The capabilities of the ASTECv2.2.0.1 [1] severe accident (SA) code along with the uncertainty quantification tool – SUNSET [2] in the coupled mode was used. The analysis was carried out for the eight input variables and ten output variables. The uncertainty quantification method incorporated within the SUNSET statistical tool was used in order to conduct the present analysis. Based on the Wilks’ formula, the number of ASTEC code runs was determined. The main statistical data are obtained for the selected fission products as figures of merit. The main steps of the analysis are outlined. Furthermore, a brief overview of the SUNSET/ASTECv2.2.0.1 coupling procedures [3] is also presented and discussed. This work demonstrates the application of the uncertainty quantification methodology in the analyses of the severe accidents in the Nuclear Power Plants and provides the specific recommendations of its use. The main outcomes from the assessment provided will be useful and may be a base for the future analyses related to the evaluation of the safety of the VVER-1000.
Feasibility Study for Minor Actinides Transmutation in Conventional Power Reactors
Authors: Mitev M , Filipov K
Published: September 2023

The handling and storage of the spent fuel from the current nuclear power reactors is one of the major ecological challenges in front of the nuclear energy industry, due to its long period of high radiotoxicity. It is mainly caused by the long-lived minor actinides generated in the nuclear fuel. Therefore profound study of the possibilities for shortening the terms of storage of spent nuclear fuels and some of high radioactive waste through the currently available technologies is necessary. The possibility for transmutation of Neptunium, Americium and Curium isotopes, as most abundant in the spent nuclear fuel of the wide-spread Light Water Reactors is evaluated in the paper using one of the most recent tools, available for the purpose. The most technologically accessible option, the current nuclear power reactors is analysed. The fuel in the cores of the LWR (PWR) and the PHWR (CANDU) type of reactors are modelled and the variation of the quantity of Neptunium, Americium and Curium isotopes after typical fuel campaigns for these reactors is estimated. The obtained results show that under the investigated conditions both types of reactors show potential for decrease of the minor actinides quantity in spent fuel before its final disposal, therefore provide a vital option toward sustainable and environmentally friendly nuclear spent fuel management.
A study on the design and production of sustainable accessories for children’s clothing
Authors: Atanasova Radka , Ivanova Miroslava , Merkova Monika
Published: September 2023

The present study directs research and creative development towards the potential of producing sustainable accessories for children’s clothing. Proposed fashion collection consists of ten models of hood-scarf. Designed hood-scarfs are “sustainable”, because they have two “faces” and are able to be combined with jackets, sweaters, vests or sweatshirts to obtain a variety of different outfits, without having to buy a number of different clothes. This leads to reducing fabric consumption. The models consist of relatively small details so that residual/waste pieces of fabric can be used for their sewing. The accuracy of the fit of products is inspected with the help of 3D virtual clothing software. This eliminates the need to sew a physical fabric sample which again leads to resource saving. The use of 3D visualization of models saves time and manpower and thus increases production efficiency. Another ecological effect is achieved, because by means of the virtual sample, the purchase decision will be made before the real product is sewn and the percentage of unrealized production in the commercial network is greatly reduced.
Flood risk assessment in urban areas in Bulgaria
Authors: Velichkova Rositsa , Angelova Radostina , Simova Iskra , Gieva Elitsa
Published: September 2023

Flooding is a phenomenon that cannot be prevented. Some human activities, such as the growth of settlements and economic assets in the floodplains, as well as the declining natural capacity of the soil to retain water caused by land use and climate change, are key factors in increasing the likelihood of floods and their adverse effects. The study is based on the data published in the National Statistical Institute Annual Reports, aiming to analyse and summarise the cases of floods in the urban areas in Bulgaria. The flood risk in the country in the period 2007-2021 is assessed for the urban areas near 17 hydrometric stations (HS). The flood index K is used to determine the areas with the highest sensitivity to floods as well as to extreme floods with significant adverse effects. The results have shown that only particular areas occasionally show high sensitivity to floods. As an average, however, for the study period, there is no area (HS) with river basins that are very sensitive to floods (K≥0.3) for the investigated period (2007-2021). Seven of the nineteen HS are sensitive to floods: Glozhene (HS2), Targovishte (HS6), Varna (HS8), Sofia-Orlandovtsi (HS12), Yambol (HS15), Burgas (HS17) and Kardzhali (HS19).
State of the Art - Drones/Surface Platforms and Green Energy
Authors: Popa Nicolae-Silviu , Popescu Mihai-Octavian , Mocanu Vlad
Published: September 2023

This paper presents a summary of what surface drones mean and the possibility of using these platforms in pollution problems. Also, in this paper, the authors have proposed to predict (in the form of a review) the possibility of producing the electricity needed for these platforms with the help of photovoltaic panels and the storage of energy in different types of batteries. This paper is a summary of what drones/surface platforms entail, the production of electricity using photovoltaic panels and an overview of battery types.
Influence of geography and weather conditions on the navigation and seaborne trade in the Black Sea
Authors: Bosneagu Romeo , Lupu Sergiu , Scurtu Ionut Cristian , Lupu Carmen Elena , Patrau Daniel Daneci , Coca Carmen Elena
Published: September 2023

The navigation on the Black Sea raises some specific issues that need to be considered, to ensure maximum safety conditions for the ship, crew, and cargo throughout the voyage. Under the current conditions of the global maritime market having a high degree of concurrency, respectively the problem of reducing fuel consumption and reducing the time needed for performing various voyages, especially in crossing the ocean on different routes, is particularly important for ship owners. The economic effect is determined by converting this time into the corresponding cost price, fuel consumption having the main percentage; to these is added the benefits increase by reducing the period of undertaking the transport contract.
An interrupted time series study of electronic health record clinical decision support for providers caring for patients with atrial fibrillation at increased stroke risk
Authors: Osterland Andrew J , Yasuda Marie , Widmer Robert J , Colavecchia Anthony C , Gums Tyler , Emir Birol , Nolen Kim , MacLean Elizabeth , Godley Paul J
Published: September 2023

Purpose

To measure the effect of clinical decision support (CDS) on anticoagulation rates in patients with atrial fibrillation (AFib) or atrial flutter (AFlut) at high stroke risk and receiving care in outpatient settings, and to assess provider response to CDS.

Methods

This observational, quasi-experimental, interrupted time series study utilized electronic health record data at a large integrated delivery network in Texas from April to November 2020. CDS consisted of an electronic Best Practice Advisory (BPA)/alert (Epic Systems Corporation, Verona, WI) with links to 2 AFib order sets displayed to providers in outpatient settings caring for non-anticoagulated patients with AFib and elevated CHA2DS2VASc scores. Weekly outpatient anticoagulation rates were assessed in patients with high stroke risk before and after implementation of CDS. Alert actions and acknowledgment reasons were evaluated descriptively.

Results

Mean (SD) weekly counts of eligible patients were 8,917 (566) before and 8,881 (811) after implementation. Weekly anticoagulation rates increased during the pre-BPA study period (β1 = 0.07%; SE, 0.02%; P = 0.0062); however, there were no significant changes in the level (β2 = 0.60%; SE, 0.42%; P = 0.1651) or trend (β3 = –0.01%; SE, 0.05%; P = 0.8256) of anticoagulation rates associated with CDS implementation. In encounters with the BPA/alert displayed (n = 17,654), acknowledgment reasons were provided in 4,473 (25.3%) of the encounters, with prescribers most commonly citing bleeding risk (n = 1,327, 7.5%) and fall risk (n = 855, 4.8%).

Conclusion

There was a significant trend of increasing anticoagulation rates during the pre-BPA period, with no significant change in trend during the post-BPA period relative to the pre-BPA period.
Seasonal variation in the xylem sap composition of six Australian trees and shrubs
Authors: Losso Adriano , Gauthey Alice , Choat Brendan , Mayr Stefan
Published: September 2023

In recent years, xylem sap composition has been shown to affect xylem hydraulics. However, information on how much xylem sap composition can vary across seasons and specifically under drought stress is still limited. We measured xylem sap chemical composition ([Ca2+], [K+], [Na+], electrical conductivity EC and pH) and surface tension (γ) of six Australian angiosperm trees and shrubs over 1 year, which comprised of exceptional dry and wet periods. Percentage losses of hydraulic conductivity and predawn leaf water potential were also monitored. In all species, measured parameters changed considerably over the annual time course. Ions and pH tended to decrease during winter months whereas γ showed a slight increase. No clear correlation was found between sap and hydraulic parameters, except for pH that was higher when plants suffered higher drought stress levels. Results indicate xylem sap composition to be complex and dynamic, where most variation in its composition seems to be dictated by season, even under severe dry conditions. However, pH might play a role as signals of drought stress.
XIII—Dear Octavia Butler
Authors: Dotson Kristie
Published: September 2023

One of Octavia Butler’s common sites of exploration concerns the impact of parenting on her main characters. She appeared to locate reproduction and child-rearing as parts of human life with great potentials for transformed futures. From a perspective of intergenerational survival, that hope appears perfectly reasonable. In this letter to Butler, I put the goal of intergenerational survival into question as an existential mandate by querying its relationship to gestative capture. Gestative capture here refers to the ready capacity to reduce an existent to immanence via their abilities to gestate ‘human’ or ‘human-like’ progeny. The conversation this letter stages with Butler and her work, which is only possible because of how clearly Butler understood gestative capture and how much she built it into her stories, asks the questions: What is ‘transcendence’ for Black women who can bear children? How ought we to imagine intergenerational survival? And when, if ever, should we put down ‘survival at all costs’ commitments?
Food supply and provisioning behavior of parents: Are small hoopoe nestlings condemned to die?
Authors: Ferrer-Pereira Paula , Martínez-Renau Ester , Martín-Vivaldi Manuel , José Soler Juan
Published: September 2023

Parents might use signals of need or of quality to decide food provisioning among their offspring, while the use of one or another signal might depend on food availability. Begging success of nestlings of different quality (i.e., body size) would also depend on food availability, and we here explore the effect of experimental food supply in begging success of nestlings and in provisioning of female hoopoes (Upupa epops), a species with extreme hatching asynchrony and nestlings size hierarchy. We video-recorded food allocation of females, begging success of nestlings of different size, and the social context (i.e., the size category of the other nestlings that were begging for food) during periods when experimental food supply was or was not available in the same nests. We found that when experimental food supplementation was present, begging success of the intermediate, but not that of large or small-sized nestlings, increased. The experiment, however, did not affect the feeding preferences of females toward nestlings of different size. Moreover, when small nestlings were the only ones that were begging for food, their begging success decreased in the experimental period, and females used supplemented prey to feed themselves. Those results, on one hand, confirm the importance of food availability for the begging success of nestlings of particular sizes and, on the other, indicate that females prefer to use extra food for their own rather than for the smallest nestlings. We discuss possible mechanisms explaining the detected experimental effects and the adaptive and nonadaptive explanations of mothers ignoring the small nestlings.
cloneRate: fast estimation of single-cell clonal dynamics using coalescent theory
Authors: Johnson Brian , Shuai Yubo , Schweinsberg Jason , Curtius Kit
Published: September 2023

Motivation

While evolutionary approaches to medicine show promise, measuring evolution itself is difficult due to experimental constraints and the dynamic nature of body systems. In cancer evolution, continuous observation of clonal architecture is impossible, and longitudinal samples from multiple timepoints are rare. Increasingly available DNA sequencing datasets at single-cell resolution enable the reconstruction of past evolution using mutational history, allowing for a better understanding of dynamics prior to detectable disease. There is an unmet need for an accurate, fast, and easy-to-use method to quantify clone growth dynamics from these datasets.

Results

We derived methods based on coalescent theory for estimating the net growth rate of clones using either reconstructed phylogenies or the number of shared mutations. We applied and validated our analytical methods for estimating the net growth rate of clones, eliminating the need for complex simulations used in previous methods. When applied to hematopoietic data, we show that our estimates may have broad applications to improve mechanistic understanding and prognostic ability. Compared to clones with a single or unknown driver mutation, clones with multiple drivers have significantly increased growth rates (median 0.94 versus 0.25 per year; P = 1.6×10−6). Further, stratifying patients with a myeloproliferative neoplasm (MPN) by the growth rate of their fittest clone shows that higher growth rates are associated with shorter time to MPN diagnosis (median 13.9 versus 26.4 months; P = 0.0026).

Availability and implementation

We developed a publicly available R package, cloneRate, to implement our methods (Package website: https://bdj34.github.io/cloneRate/). Source code: https://github.com/bdj34/cloneRate/.
VoDEx: a Python library for time annotation and management of volumetric functional imaging data
Authors: Nadtochiy Anna , Luu Peter , Fraser Scott E , Truong Thai V
Published: September 2023

In functional imaging studies, accurately synchronizing the time course of experimental manipulations and stimulus presentations with resulting imaging data is crucial for analysis. Current software tools lack such functionality, requiring manual processing of the experimental and imaging data, which is error-prone and potentially non-reproducible. We present VoDEx, an open-source Python library that streamlines the data management and analysis of functional imaging data. VoDEx synchronizes the experimental timeline and events (e.g. presented stimuli, recorded behavior) with imaging data. VoDEx provides tools for logging and storing the timeline annotation, and enables retrieval of imaging data based on specific time-based and manipulation-based experimental conditions.

Availability and implementation

VoDEx is an open-source Python library and can be installed via the “pip install” command. It is released under a BSD license, and its source code is publicly accessible on GitHub (https://github.com/LemonJust/vodex). A graphical interface is available as a napari-vodex plugin, which can be installed through the napari plugins menu or using “pip install.” The source code for the napari plugin is available on GitHub (https://github.com/LemonJust/napari-vodex). The software version at the time of submission is archived at Zenodo (version v1.0.18, https://zenodo.org/record/8061531).
Acoustic wave propagation in a porous medium saturated with a Kelvin–Voigt non-Newtonian fluid
Authors: Ba Jing , Fang Zhijian , Fu Li-Yun , Xu Wenhao , Zhang Lin
Published: September 2023

Wave propagation in anelastic rocks is a relevant scientific topic in basic research with applications in exploration geophysics. The classical Biot theory laid the foundation for wave propagation in porous media composed of a solid frame and a saturating fluid, whose constitutive relations are linear. However, reservoir rocks may have a high-viscosity fluid, which exhibits a non-Newtonian (nN) behaviour. We develop a poroelasticity theory, where the fluid stress-strain relation is described with a Kelvin–Voigt mechanical model, thus incorporating viscoelasticity. First, we obtain the differential equations from first principles by defining the strain and kinetic energies and the dissipation function. We perform a plane-wave analysis to obtain the wave velocity and attenuation. The validity of the theory is demonstrated with three examples, namely, considering a porous solid saturated with a nN pore fluid, a nN fluid containing solid inclusions and a pure nN fluid. The analysis shows that the fluid may cause a negative velocity dispersion of the fast P(S)-wave velocities, that is velocity decreases with frequency. In acoustics, velocity increases with frequency (anomalous dispersion in optics). Furthermore, the fluid viscoelasticity has not a relevant effect on the wave responses observed in conventional field and laboratory tests. A comparison with previous theories supports the validity of the theory, which is useful to analyse wave propagation in a porous medium saturated with a fluid of high viscosity.
A geraniol synthase regulates plant defense via alternative splicing in tea plants
Authors: Jiang Hao , Zhang Mengting , Yu Feng , Li Xuehui , Jin Jieyang , Zhou Youjia , Wang Qiang , Jing Tingting , Wan Xiaochun , Schwab Wilfried , Song Chuankui
Published: September 2023

Geraniol is an important contributor to the pleasant floral scent of tea products and one of the most abundant aroma compounds in tea plants; however, its biosynthesis and physiological function in response to stress in tea plants remain unclear. The proteins encoded by the full-length terpene synthase (CsTPS1) and its alternative splicing isoform (CsTPS1-AS) could catalyze the formation of geraniol when GPP was used as a substrate in vitro, whereas the expression of CsTPS1-AS was only significantly induced by Colletotrichum gloeosporioides and Neopestalotiopsis sp. infection. Silencing of CsTPS1 and CsTPS1-AS resulted in a significant decrease of geraniol content in tea plants. The geraniol content and disease resistance of tea plants were compared when CsTPS1 and CsTPS1-AS were silenced. Down-regulation of the expression of CsTPS1-AS reduced the accumulation of geraniol, and the silenced tea plants exhibited greater susceptibility to pathogen infection than control plants. However, there was no significant difference observed in the geraniol content and pathogen resistance between CsTPS1-silenced plants and control plants in the tea plants infected with two pathogens. Further analysis showed that silencing of CsTPS1-AS led to a decrease in the expression of the defense-related genes PR1 and PR2 and SA pathway-related genes in tea plants, which increased the susceptibility of tea plants to pathogens infections. Both in vitro and in vivo results indicated that CsTPS1 is involved in the regulation of geraniol formation and plant defense via alternative splicing in tea plants. The results of this study provide new insights into geraniol biosynthesis and highlight the role of monoterpene synthases in modulating plant disease resistance via alternative splicing.
Safety and Immunogenicity of a Revaccination With a Respiratory Syncytial Virus Prefusion F Vaccine in Older Adults: A Phase 2b Study
Authors: Leroux-Roels Isabel , Van Ranst Marc , Vandermeulen Corinne , Abeele Carline Vanden , De Schrevel Nathalie , Salaun Bruno , Verheust Céline , David Marie-Pierre , Kotb Shady , Hulstrøm Veronica
Published: September 2023

Background

In the previous (parent) study, 2 doses of different formulations of an investigational vaccine against respiratory syncytial virus (RSVPreF3 OA) were well tolerated and immunogenic in older adults. This multicenter phase 2b extension study assessed safety and immunogenicity of a revaccination (third) dose of the 120 μg RSVPreF3-AS01E formulation.

Methods

In total, 122 older adults (60–80 years), previously vaccinated with 2 doses of RSVPreF3-AS01E formulations (containing 30, 60, or 120 μg RSVPreF3 antigen), received an additional 120 μg RSVPreF3-AS01E dose 18 months after dose 2. Vaccine safety was evaluated in all participants up to 6 months and immunogenicity in participants who received 120 μg RSVPreF3-AS01E doses until 1 month after dose 3.

Results

Similar to the parent study, mostly mild-to-moderate solicited adverse events and no vaccine-related serious adverse events or potential immune-mediated disorders were reported. Neutralizing titers and cell-mediated immune responses persisted for 18 months after 2-dose vaccination. Dose 3 increased RSV-specific neutralizing titers against RSV-A and RSV-B and median CD4+ T-cell frequencies. After dose 3, RSV-specific neutralizing titers but not CD4+ T-cell frequencies were below levels detected 1 month after dose 1.

Conclusions

Revaccination with 120 μg RSVPreF3-AS01E 18 months after dose 2 is well tolerated and immunogenic in older adults.

Clinical Trials Registration

NCT04657198; EudraCT, 2020-000692-21.