bluuebunny/crossref_metadata_2025 huggingface dataset:
A Torsional Negative Poisson’s Ratio Structure: Dynamics and Energy Absorption Performance
Authors: Wang Shuai , Chen Zhuo , Li Jialu , Wang Xin , Zhen Zixuan
Published: August 2023

The crash box’s internal structure can be designed to absorb more energy in a significant way. Using the finite element method, this paper investigates a structure with a negative Poisson ratio and a self-torsion effect. The arrangement and combination of eight structures have a torsional Poisson ratio that is negative. The optimal energy absorption of LCHC-B structures, as determined by simulation analysis, results in an excellent performance. Due to structural asymmetry, the LCHC-B structure has large deformation characteristics and self-torsion, making the structure’s displacement greater than that of the conventional negative Poisson ratio structure and exhibiting excellent energy absorption properties.
Heat treatment enhancing the hydraulic fracturing performances of Al-Cu-Ga-In-Sn alloys
Authors: Wang Shaocheng , Wang Sibo , Tu Dianya , Huang Linjiang , Qu Yijia
Published: August 2023

For improving the mechanical properties of Al-Ga-In-Sn alloys used to make dissolvable hydraulic fracturing tools, the effects of Cu and heat treatment on the microstructures and the Al-water reactivities of Alloys with Cu addition were investigated. The XRD and SEM were employed to investigate their microstructures. When the Cu content of alloys is above 1 wt%, Cu can dissolve in Al grains and form CuAl2 phases at Al grain boundaries, which can strengthen Al-Cu-Ga-In-Sn alloys. Cu will not form intermetallic compounds with Ga, In, and Sn, so liquid GIS phases are still observed at Al grain boundaries. The Cu and Ga atoms can diffuse from CuAl2 and GIS phases to Al grains during solution treatment. The CuAl2 phases can precipitate in Al grains during the artificial aging treatment of alloys. The increment of Cu, and Ga contents of Al grains, and the formed CuAl2 precipitates in Al grains will further strengthen the heat treatment alloys. Al-water reactivities of as-cast and heat treatment alloys were performed in different water temperatures. The solute Cu in Al grains and CuAl2 phases at Al grain boundaries will occupy the contacting sites for Al reacting with water, leading to H2 generation rates and H2 yield of reactivity of Cu-bearing alloys with water decreasing. After heat treatment, the increment of Cu content and CuAl2 precipitates in Al grains will occupy more contacting sites for Al reacting with water, resulting in a lower H2 yield of Al-water reaction of heat treatment alloys than that of as-cast alloys.
The Effect of Steel Fiber Length-to-Diameter Ratio and Dosing on the Mechanistic Characteristics of Concrete
Authors: Li Jiuyang , Wang Zhenwei , Chen Li , Guo Jinpeng , Hu Guangchao
Published: August 2023

In this paper, the effects of three kinds of steel fibers with different aspect ratios on the slump, compressive intensity, and splitting tensile strength of concrete were studied. The results show that the slump for the steel fiber-based polished concrete reduces with the amount of admixture of steel foundation. The slump of concrete with steel fibers of larger length and diameter is reduced at the same volume of admixture. The compressive intensity and the cleavage intensity of the concrete mixed with steel fibers are increased to different degrees than the vegetal one. Among them, the average decompressive force is increased by nearly 15%, and the cleavage tensile strength is significantly increased. It is indicated that the cracking characteristics of the steel fiber concrete have also been improved, and the toughness of the concrete has been enhanced.
Effect of Ultrasonic Treatment on Microstructure and Properties of Gray Cast Iron
Authors: Ya Bin , Ji Shengchen , Meng Linggang , Zhou Bingwen , Ning Hangbo , Lou Xinyu , Li Xiaoyan , Jiang Ailong , Du Jizhu , Zhang Xingguo
Published: August 2023

The effect of ultrasonic treatment on the microstructure and properties of gray cast iron was studied. The samples were analyzed by metallographic microscope, scanning electron microscope, Brinell hardness tester, electronic universal testing machine, etc. The results showed that ultrasonic treatment could improve the pearlite content in the microstructure. After ultrasonic treatment, the tensile strength of gray cast iron can be improved to 266 MPa, which is 11.60% higher than that of the samples without ultrasonic treatment. Ultrasonic treatment can refine the size of graphite, which can reduce the stress concentration. In addition, the pearlite lamellar spacing can also be reduced, which is the main reason for improving the mechanical properties of gray iron.
Stress evolution of TBCs considering the micro morphology characteristics with multi-oxides growth
Authors: Du Hao , Chai Yijun , Yang Xiongwei , Li Yueming
Published: August 2023

Thermal Barrier Coatings (TBCs) are a fundamental technology for safeguarding aircraft engine blades from high-temperature environments. Under long-term exposure to a high-temperature environment, breakaway oxidation of multi-metallic metals occurs in TBCs. The growth of multi-metal oxides and stress evolution in the TBCs after breakaway oxidation is very complex for a real coating microscopic morphology. In this paper, we use the CT image technology to construct the TBCs model of the reflective TBCs microscopic morphology and use a user-defined element (UEL) subroutine involving the growth of the multi-oxides model to calculate the stress. We focus on the evolution of interfacial stress in the first and second oxide stages. The results show that the micro defects will cause multiple increases in the maximum stress near the defects in TBCs. Meanwhile, microscopic defects near the interface can bring a sharp increase of tensile stress in the local area during the cooling stage, which can easily cause cracking and delamination of the interface.
Finite element research on anti-seismic property of precast reinforced concrete frame with damped joint of beam and column
Authors: Wu Zhong-tie , Xie Ning
Published: August 2023

To research the anti-seismic performance of prefabricated concrete structures with damped beam-column joints, several different types of finite element patterns were set up by ABAQUS finite element software. The analysis of the low-cycle repeated loading test was conducted. This paper mainly studied the lose efficacy mode, hysteresis loop, skeleton curve, drawability, rigidity degeneration, and energy consumption ability of a prefabricated concrete frame with a damped beam-column joint. It discussed the influence of different forms of filling materials and axial pressure ratio on their seismic performance. The results showed that the rubber hardness had a minor effect on the nonlinear mechanical properties of the frame. The larger the axial pressure ratio is, the greater the bearing ability of the damping frame is. The smaller the stiffness degradation is, the lower the ductility performance is. When the axial pressure ratio is small to a certain numerical value, the frame lose efficacy will change. The prefabricated frame with a damped beam-column joint has good seismic performance.
Experimental Study on Mechanical Response of Oil and Gas Pipelines under Ground Subsidence
Authors: Lin Liang , Lou Yuhuai , Guan Enjun , Ding Fengbin , Ding Xiaolin , Zhang Yu
Published: August 2023

At present, accidents of buried pipelines caused by localized ground subsidence are reported frequently. Understanding the mechanical response of pipe soil during subsidence is of great significance to the safe operation of buried pipelines. This paper studies the stress state of buried oil and gas pipelines and their surrounding soil through a series of large-scale model tests in the process of localized ground subsidence. The experiment results show that during the process of subsidence, the axial and hoop strain of the pipeline increases with the expansion of the subsidence area and the subsidence amount. The subsidence amount has a relatively greater influence, and the distribution characteristics of the pipeline strain present obvious regional characteristics. The earth pressure around the pipe shows different changes in the process of subsidence, among which the earth pressure on the upper part of the pipe is the main one. The research results can provide a certain reference for the design and calculation of oil and gas pipelines under foundation settlement.
Application of laser cable measuring systems in production
Authors: Ma Yue , Yue Mingkai , Li Hongda
Published: August 2023

In order to meet the need of testing cable quality parameters during the production process and make the cable parameters reach the allowable error of the national standard, a design scheme of a laser cable measurement system is proposed. The laser cable measurement system consists of the laser measurement system and data processing system. With ARM as the core controller, the laser and linear CCD sensor are used for online detection and data processing of the cable outer diameter, and the cable outer diameter can be accurately measured without contact. The laser cable measurement system can be directly applied to the cable production line to measure the cable in real time. Under the working conditions of the production line, the system has a simple structure, high precision and good application prospect.
Design of strain sensors using highly entangled hydrogel: high resolution, large detection range, and low hysteresis
Authors: Zheng Haotian , Han Yuwei , Wang Zhigang , Li Wei , Lu Yifei , Zhang Shuwen , Jia Kun
Published: August 2023

Stretchable strain sensors with high performance are desirable for sports health monitoring, human-computer interaction, and soft machines. Sensors using polyacrylamide hydrogels with long chains have good stretchability and low hysteresis but limited resolution at small deformation. Here, we design stretchable strain sensors using highly entangled polyacrylamide hydrogels with high modulus and low hysteresis. The high modulus ensures the solid behavior of the material, making the elongation at small deformation detectable, and the resolution can be up to 0.2%. The sensor can measure the elongation of elastomers within the range of 200%. The change of relative resistance maintains low hysteresis and is repeatable over tests of 1000 cycles. The hydrogel sensor with water-retaining encapsulation exhibits electrical stability for a long time.
P … π Bonds in Complexes of C2H2 … PH2X (X = H, F, Cl, Br, I): Quantum Chemical Analysis
Authors: Luo Jun , Li Xiaofeng , Xiang Dingding , Zeng Chenglu , Dai Hongjing , Wu Dawang , Cao Maoqi
Published: August 2023

Non-covalent bonds take a strong in numerous chemical and biological phenomena, bringing them to the forefront of research. We studied the structure and interaction properties of C2H2 and PH2X using quantum chemistry following the Moller-Plesset method (MP2). The results showed that C2H2 and PH2X could form a stable complex (C2H2 … PH2X (X= H, F, Cl, Br, I)) of Cs symmetry. The halogen X was far away from the C2H2 molecule, and the P atom was not directly above the center of the C≡C bond. The molecular interaction energy of C2H2 … PH2X varied between -6.3 and -14.5 kJ/mol. This revealed the generation of a long-range weak interaction. Analysis of the interaction energy revealed that the substitution of halogen atoms promoted the formation of the complex (C2H2 … PH2X). The interaction energy of the complex decreased in the order F>Cl>Br>I, which was consistent with the change in electronegativity of the halogen atoms. Independent Gradient Model (IGM) analysis calculations showed that van der Waals interaction was the dominant weak interaction in C2H2 … PH2X. The symmetry-adapted perturbation theory (SAPT) was used to study the system, and the results revealed that the interactions in C2H2 … PH3, C2H2 … PH2I were primarily dispersive, and the interactions in C2H2 … PH2F, C2H2 … PH2Cl, C2H2 … PH2Br were primarily electrostatic.
In Situ SEM Compression Study on Micro-mechanical Behavior of Electron Beam Melted Ti-6Al-4V Alloy
Authors: Li Zhenkai , Yan Yabin
Published: August 2023

To investigate the mechanical properties of electron beam melted (EBM) Ti-6Al-4V alloy at the microscale, a series of in situ scanning electron microscope (SEM) compression experiments were performed in the current study. Firstly, a reconstruction of the original β phase of Ti-6Al-4V alloy was conducted using electron backscattering diffraction (EBSD) analysis. Micro-pillars were subsequently fabricated with a diameter of 2 μm within the same original β phase grain, and yield strength was measured using an in-situ mechanical compression device. The mechanical response of each micro-pillar was found to vary, and potential reasons for this phenomenon were discussed, including the impact of α-phase and β-dispersion on the material’s mechanical properties. Moreover, a clear size effect was observed when comparing the yield strength of the bulk material. Furthermore, the plastic deformation behavior of Ti-6Al-4V alloy was also investigated through compression tests on the micro-pillars.
Construction of Graphene-Paper Flexible Pressure Sensor
Authors: Feng Yanqing , Sun Junhui , Zhang Guocai , Shen Yang , You Yong
Published: August 2023

Combining with flexible materials, two-dimensional nanomaterial graphene can effectively improve the mechanical and electrical properties of composites for flexible sensors, which has broad application prospects in health monitoring and human wearable devices. Here, we designed a sandwich paper-based flexible graphene sensor. The amplification and circuit were constructed to realize the acquisition and display of voltage signals caused by micro-strain to achieve the purpose of pulse signal detection. The qualitative and quantitative fabrication process parameters studies were conducted through experiments to make the sensor have high conductivity and sensitivity.
Reinforcing Poly (Metaphenylene Isophthalamide) Fibers by Cellulose Nanocrystal
Authors: Song Qingquan , Yu Junrong , Wang Yan
Published: August 2023

Typical poly (metaphenylene isophthalamide) fibers exhibit excellent heat resistance and excellent flame retardancy but very poor breaking strength, which limits their diversified applications severely. Therefore, it becomes urgently important to develop new strategies to improve their breaking strength. In this regard, a new composite fiber was prepared by wet spinning through a blend solution of poly (metaphenylene isophthalamide) and cellulose nanocrystals. Poly (metaphenylene isophthalamide) composite fibers with excellent breaking strength blended with cellulose nanocrystals were prepared through a simple and scalable blending strategy. In contrast to the pristine poly (metaphenylene isophthalamide) fiber, its mechanical properties were significantly improved, such as maximum breaking strength of 4.89 cN/dtex, which is 86.8% higher than pristine poly (metaphenylene isophthalamide) fiber. This work provides a new way of thinking to fabricate high-performance poly (metaphenylene isophthalamide) fibers for high-tech applications.
Selective extraction of lithium from spent LiCoO2 cathodes by two-step calcination with ammonium chloride
Authors: Wei Dai-xiang , Wang Wei , Jiang Long-jin , Chang Zhi-dong , Dong Bin , Gao De-kun , Anwar Hira
Published: August 2023

This paper reported a strategy for selective lithium extraction from spent LiCoO2 (LCO) cathodes by two-step chlorination calcination combined with water-leaching. The feasibility of selective lithium extraction by two-step chlorination calcination was predicted by the thermodynamic analysis. The elements of Li and Co in the LiCoO2 cathode material were converted into water-soluble LiCl and CoCl2 respectively after pretreatment at 350 °C. Afterward, the generated CoCl2 reacted with the remaining LiCoO2 and converted into water-soluble LiCl and water-insoluble Co3O4 with temperatures increased. The results showed that 96.56% of the lithium can be recovered as LiCl and 95.23% Co in the form of Co3O4.
MPPT study of PV cells in complex environments
Authors: Zhou Haoran , Zhang Xiaohong
Published: August 2023

In operation, the solar power generating system’s output power from the photovoltaic array is sensitive to external conditions including light intensity and temperature, and displays typical non-linear characteristics. Hence, monitoring the maximum output power of PV cells in real time is necessary to guarantee that the maximum power output of PV cells is constantly maintained, enhancing the efficiency with which PV cells are used. Therefore, this paper is based on the immune algorithm, simulates that the biological immune system will be affected by the antigen infestation and produce resistance to carry out antigen recognition, memory, and other immune response reactions through MATLAB / Simulink simulation, and adopts the traditional perturbation observation method. The results of the simulation show that the Composite algorithm has the benefits of high tracking accuracy, fast tracking speed, stable tracking, and low false positives.
The effect of the degree of sulphenylation on the stability of reduced graphene oxide nanofluids
Authors: Wang Yi
Published: August 2023

Dispersion stability of nanoparticles in nanofluids is a prerequisite for allowing the nanofluids to act as convection heat transfer working fluids. This research prepared multiple types of sulfophenylated graphene (PSG) nanoparticles. Two samples subjected to different degrees of sulfophenylation were chosen to formulate different nanofluids with varying sulfophenylated particle concentrations. The nanofluids’ measured Zeta potential, electric conductivity, and thermal conductivity coefficients were used to investigate the stability. The research indicates the increase in the degree of sulfophenylation can improve the stability of nanofluids while exerting little influence on thermal conductivity; on the premise of ensuring stability, the number of nanoparticles added in base fluids can increase thermal conductivity. After that, high-sulfophenylated particle concentration nanofluids (2 mg/mL) were formulated using sulfonated-reduced graphene oxide (s-rGO) nanoparticles prepared to demonstrate excellent stability, and their thermal conductivity reached 0.773 W/m. K (55 °C).
Synthesis and application of mixed conductive and oxygen-permeable materials based on BaFeO3-δ
Authors: Shao Yan , Fu Zaiguo , Yuan Binxia , Lei Yanhua , Quan Changling , Zhu Qunzhi
Published: August 2023

Cobalt-free perovskite oxide BaFeo3-δ (BFO) exists in mixtures with various phase structures and exhibits poor oxygen ion conductivity, thereby limiting its application as a cathode material in solid oxide fuel cells (SOFC). In this study, the stabilization of a single cubic phase structure of BFO through doping with Gd at the A-site or Cu at the B-site and the lowest temperature required for the synthesis of such a structure are investigated. A large fraction of adsorbed oxygen atoms and a low valence state of Fe are found in BaFe0.9Cu0.1O3-δ, resulting in improved performance. Furthermore, the ideal sintering temperatures for Ba0.9Gd0.1FeO3-δ cathode and BaFe0.9Cu0.1O3-δ cathode are 900 °C and 850 °C, respectively. At 700 °C, the polarization resistance of the BaFe0.9Cu0.1O3-δ cathode is 0.439 Ω·cm2 and that of the Ba0.9Gd0.1FeO3-δ cathode is 0.545 Ω·cm2.
Design and preparation of carbon fiber, carbon particle doped C4H10O4 phase change thermal storage materials and performance
Authors: Chen Bingnan , Liu Jun
Published: August 2023

C4H10O4 is an environmentally friendly phase change material that can release high phase change enthalpy, but its high super-cooling degree and low thermal conductivity hinder its wide application. This paper adopted C4H10O4 as a phase change material, and the composite phase change material was prepared by melting and blending C4H10O4 with carbon fiber, carbon particles. The results indicate that the composite phase change material with 1.5% filler has better comprehensive properties. Compared with pure C4H10O4, 167% improvement in thermal conductivity, the under-cooling decreases by 42%, and 3% increase in enthalpy of phase change. FT-IR analysis shows that no new substances are produced, and TG analysis shows that the chemical stability is good. Heat storage/release analysis shows that the exothermic time reaches 4 hours, and the exothermic time is 5 °C higher.
Optimal scheduling of integrated energy systems with carbon and hydrogen storage based on IGDT
Authors: Qu Meining , Bai Di
Published: August 2023

To deal with the uncertainties that the integrated energy system will encounter during operation, we propose an optimal scheduling strategy for the integrated energy system considering carbon and hydrogen storage. First, a comprehensive energy system containing a carbon capture system (CCS), power-to-gas technology (P2G), photothermal power station, and other equipment is established, and the combined operation of CCS and P2G is considered. Secondly, the carbon storage device and hydrogen storage device were respectively applied to the carbon capture system and P2G device, and the optimal scheduling model of the comprehensive energy system containing carbon storage and hydrogen storage was constructed. The operational constraints of the energy system will be integrated and the flexibility of the system will be improved. Finally, considering the dual uncertainties of the system source and load, a robust model and a chance model are constructed based on the Information Gap Decision Theory (IGDT). The economy of the real model and the influence of uncertainty on the whole system can be verified by close to real examples.
Facile Synthesis of Nitrogen Doped Porous Carbon Supported Platinum Catalyst and Improvement of Electrocatalytic Ethanol Performance
Authors: Ren Guohong , Chen Yuting , Liu Chunyu , Dong Xingzheng , Xu Yi , Chen Hong , Chen Qianqian , Shi Xiaohua , Liu Zhongsu
Published: August 2023

Direct ethanol fuel cells (DEFCs) have become an alternative to traditional fossil fuels because of their low emissions, fast start-up and high energy density. Platinum (Pt)-based catalysts are the most effective catalysts for DEFCs, but their high cost and poor electrocatalytic performance hinder their practical application. Therefore, there is an urgent need to design Pt-based catalysts with low platinum content, high electrochemical activity and stability. Herein, nitrogen-doped porous carbon-loaded Pt catalysts (Pt@Co-CN) were prepared by in situ polymerization and high-temperature calcination using the metal-organic framework materials (MOFs) ZIF-8@ZIF-67 as the carriers. The effects of the addition of pyrrole monomer on the morphology and electrocatalytic properties of the samples were investigated. The sample with the complete coating layer and uniformly dispersed Pt nanoparticles (Pt@Co-CN) could be obtained by adding an appropriate amount of pyrrole monomer. The results of the electrochemical tests showed that the electrochemical activity of Pt@Co-CN catalytic ethanol is superior to that of commercial catalysts and samples with insufficient or excessive addition of pyrrole monomers. The content of this study provides a new method for the electrocatalyst of DEFCs.
The effect of the backfill on the integrity of a buried pipeline upon heavy-duty vehicle crossings
Authors: Gajdoš Ľ , Šperl M , Slížková Z , Drdlová M
Published: August 2023

The aim of this work was to determine stresses in the wall of a buried empty gas pipeline caused by the weight of backfill as well as by heavy-duty vehicles crossing the pipeline, and, on their basis to assess the applicability of protective sleeves. A buried pipeline with zero internal pressure of transported medium (empty pipeline) differs from an unburied pipeline by the vertical load due to the weight of the backfill which causes an ovalness of the circular cross section of the pipeline. This leads to the rise of through-wall bending stresses with the tensile stress at the outside surface at the 3 and 9 o´clock positions and compressive stress at the inside surface. At the 6 and 12 o´clock positions the stresses are tensile at the inside surface and compressive at the outside surface. The current depth of soil cover above gas pipelines is 0.5 m. For pipes DN500, t ~ 6.5 mm the through-wall bending stress is found to be σb ≈ ±10 MPa. In comparison with the yield stress of pipeline material, this stress is negligible. The situation is changed when heavy-duty vehicles cross the pipeline. For example, when a MAN truck with the mass load 3270 kg acting on a single wheel of the front axle crosses this pipeline, the pressure transmitted to the pipe will cause the through-wall bending stress σb ≈ ±76 MPa. This stress is superimposed to that of the backfill to give the total value ±86 MPa. When dead loads, imposed by backfill cover, together with live loads, caused by truck-wheel loads, are excessive a crushing of side walls of the pipeline and/or ring buckling of the pipe cross section can happen.
Accumulated dose implications from systematic dose-rate transients in gated treatments with Viewray MRIdian accelerators
Authors: Klavsen M F , Ankjærgaard C , Boye K , Behrens C P , Vogelius I R , Ehrbar S , Baumgartl M , Rippke C , Buchele C , Renkamp C K , Santurio G V , Andersen C E
Published: August 2023

The combination of magnetic resonance (MR) imaging and linear accelerators (linacs) into MR-Linacs enables continuous MR imaging and advanced gated treatments of patients. Previously, a dose-rate transient (∼8% reduced dose rate during the initial 0.5 s of each beam) was identified for a Viewray MRIdian MR-Linac (Klavsen et al 2022 Radiation Measurement 106759). Here, the dose-rate transient is studied in more detail at four linacs of the same type at different hospitals. The implications of dose-rate transients were examined for gated treatments. The dose-rate transients were investigated using dose-per pulse measurements with organic plastic scintillators in three experiments: (i) A gated treatment with the scintillator placed in a moving target in a dynamic phantom, (ii) a gated treatment with the same dynamic conditions but with the scintillator placed in a stationary target, and (iii) measurements in a water-equivalent material to examine beam quality deviations at a dose-per-pulse basis. Gated treatments (i) compared with non-gated treatments with a static target in the same setup showed a broadening of accumulated dose profiles due to motion (dose smearing). The linac with the largest dose-rate transient had a reduced accumulated dose of up to (3.1 ± 0.65) % in the center of the PTV due to the combined dose smearing and dose-rate transient effect. Dose-rate transients were found to vary between different machines. Two MR-Linacs showed initial dose-rate transients that could not be identified from conventional linearity tests. The source of the transients includes an initial change in photon fluence rate and an initial change in x-ray beam quality. For gated treatments, this caused a reduction of more than 1% dose delivered at the central part of the beam for the studied, cyclic-motion treatment plan. Quality assurance of this effect should be considered when gated treatment with the Viewray MRIdian is implemented clinically.
Fast assessment of the voltage stability using reconfigured power system network and artificial neural network approaches
Authors: Gupta Santosh Kumar , Mallik Sanjeev Kumar
Published: August 2023

Planning and running power systems must take voltage stability into account. Instability is mostly caused by the power system’s failure to supply the demand for reactive power. The voltage stability margin must be understood by utilities if they are to operate the power system with the highest level of security and dependability. This paper uses reconfigured 12 bus, 10 bus, and 8-bus reconfigured networks of the interconnected IEEE 14 bus system to demonstrate the proposed quick method for assessing the voltage stability. The original (IEEE 14 bus) and the reconfigured (12 bus, 10 bus, and 8-bus) systems’ voltage stability has been evaluated using the line stability index indicators: fast voltage stability index (FVSI), line voltage stability index (LVSI), and line stability index (Lmn). Based on the maximum loadability factor, the contingencies for the original and reconfigured systems are ranked. The system loadability factor is used as the input parameter, and the LVSI, Lmn, and FVSI indices for the critical line under critical contingency are used as an output to train the ANN network. It has been found that there is no discernible difference between the actual (NR method) and predicted (ANN approach) output. For accessing the voltage stability of the IEEE 14 bus system by its reconfigured networks using the proposed approach, the computational time and error are very low, showing the effectiveness, rapidity, and accuracy of the suggested approach.
Diversity of free-living flatworms (Platyhelminthes) in Cuba
Authors: Diez Yander L , Sanjuan Claudia , Bosch Camila , Catalá Alejandro , Monnens Marlies , Curini-Galletti Marco , Artois Tom
Published: August 2023

Cuban biodiversity is characterized by high species richness and endemism; however, free-living flatworms have been neglected in studies of the fauna of the archipelago. These animals constitute an essential component of marine and freshwater ecosystems as top predators and secondary producers. In this contribution, we provide the first comprehensive analysis of turbellarian diversity in Cuba based on a long-term sampling effort in marine, brackish, freshwater and terrestrial environments. We used observed and estimated species richness as indicators of alpha diversity. As a result, we have collected, for the first time, 279 species in Cuba, including 189 species of rhabdocoels, 33 species of polyclads, 21 species of macrostomorphs, 14 species of proseriates, 12 species of prolecithophorans, seven species of triclads and one representative each of Prorhynchida, Gnosonesimida and Bothrioplanida. At least 184 species (67%) are new to science. Fifty of these species have been recorded in published journal contributions. The remainder are pending formal identification and/or description. We demonstrate the turbellarian fauna of Cuba to be one of high diversity and endemism. Estimated species richness is much higher than that observed, exemplifying the taxonomic impediments and stressing the need for more intense sampling campaigns in the archipelago.
Burdened but Meaningful?: How Gender Role Attitudes Influence the Complex Links between Care-giver Self-Efficacy, Formal Support Utilisation and Benefit-Finding among Spousal Care-givers
Authors: Yan Zi , Zhang Jiyuan , Sun Xin
Published: August 2023

To foster family caregiving resilience, helping care-givers find benefits to further promoting care-giver and care-recipient well-being has emerged as an efficacious intervention in geriatric social work practice. This cross-sectional mixed-methods study investigates how gender role attitudes influence the complex associations between care-giver self-efficacy, formal support utilisation and benefit-finding among spousal care-givers. A total of 210 spousal care-giver/care-recipient dyads from four Chinese cities participated in a survey from July to August 2021. The survey used the Positive Aspects of Caregiving Scale, Caregiver Task Inventory Scale and Gender Role Attitude Scale. Mediation and moderated mediation analysis found that care-giver self-efficacy partially mediated the path of the primary stressor and benefit-finding; formal support utilisation directly moderated the mediated pathways linking primary stressor, care-giver self-efficacy and benefit-finding; and gender role attitudes moderated these intersections. Qualitative analysis revealed that spousal care-givers with high self-efficacy, who used formal support services, and who had modern gender role attitudes found the most benefits in caregiving. The findings also suggested that professionals should recognise the influence of gender role attitudes in spousal caregiving and incorporate this understanding into the development of tailored psychoeducational interventions aimed at promoting care-giver well-being.
Limitation of gene flow by distance in the common yellow jasmine (Chrysojasminum fruticans, Oleaceae): implications for the study of its mating strategies
Authors: Puyoou Aurore , Gryta Hervé , Fuchs Anne-Laure , Blanchard Pierrick , Cheptou Pierre-Olivier , Civeyrel Laure , Dufay Mathilde , Dupin Julia , Jargeat Patricia , Lecompte Emilie , Besnard Guillaume
Published: August 2023

The common yellow jasmine (Chrysojasminum fruticans, Oleaceae) is a distylous shrub occurring in the wild in south-western Europe and the Mediterranean Basin. Little is known about the genetics of its populations and such information would be necessary to investigate its spread and mating strategies. Here, the organization of its genetic diversity was investigated among and between 13 populations from southern France, including a 35-year-old experimental plot (‘CEFE’, CNRS Montpellier). Markers (microsatellites and indels) were developed to screen polymorphisms in nuclear, chloroplast, and mitochondrial genomes. Low linkage disequilibrium was observed between chloroplast and mitochondrial haplotypes probably resulting from paternal leaks in their inheritance as reported in other species of tribe Jasmineae. Yet, analyses of 36 progenies issued from parents with distinct chloroplast and/or mitochondrial DNA haplotypes only revealed a maternal contribution. Natural populations of C. fruticans are moderately to highly differentiated at the regional scale with a strong isolation-by-distance pattern detected on nuclear data, indicating limited gene flow. An isolated site (‘Moulis’), located on the marginal distribution area, was remarkably genetically depauperate and highly differentiated from other populations. Further studies on the variation of mating strategies in C. fruticans should consider populations with contrasting patterns of genetic diversity. The artificial ‘CEFE’ population also offers opportunities for experiments in a closed system.
Are there sex differences in cardiovascular outcomes in non-dialysis CKD patients?
Authors: Provenzano Pasquale Fabio , Caridi Grazia , Parlongo Giovanna , Leonardis Daniela , Puntorieri Elvira , Tripepi Giovanni , Zoccali Carmine , Mallamaci Francesca
Published: August 2023

Background

Sex differences for cardiovascular (CV) risk and outcomes in chronic kidney disease (CKD) patients not on dialysis have been scarcely or never investigated. We therefore studied this important aspect in a cohort of CKD stage 2–5 in the south of Italy.

Methods

We tested the relationship between sex and fatal and non-fatal major CV events in a cohort of 759 stage 2–5 CKD patients followed up for a median time of 36 months.

Results

Out of 759 patients, 455 were males (60%) and the remaining 304 patients were females (40%). During the follow-up, 42 patients died, and 118 had fatal and non-fatal CV events. On univariate Cox regression analyses, the male sex failed to be associated with all-cause mortality but was strongly related to the incidence rate of fatal and non-fatal major CV events [hazard ratio (HR) 1.75, 95% confidence interval (CI) 1.18–2.60, P = .006]. Data adjustment for a series of major potential confounders did not materially affect the strength of this relationship (HR 1.78, 95% CI 1.03–3.09). Further analysis testing the effect of age on major CV outcomes by sex showed an effect modification by this risk factor on the same outcome (P = .037) because the HR of male versus female CV events increased progressively with aging.

Conclusion

Male patients in stage G2–5 CKD had a higher risk for CV events compared with female patients. Age was shown to be a risk modifier for the association between sex and CV events and this risk increased linearly across a wide age spectrum in CKD patients.
Tissue-specific transcriptomes reveal potential mechanisms of microbiome heterogeneity in an ancient fish
Authors: Thorstensen Matt J , Weinrauch Alyssa M , Bugg William S , Jeffries Ken M , Anderson W Gary
Published: August 2023

The lake sturgeon (Acipenser fulvescens) is an ancient, octoploid fish faced with conservation challenges across its range in North America, but a lack of genomic resources has hindered molecular research in the species. To support such research, we created a transcriptomic database from 13 tissues: brain, esophagus, gill, head kidney, heart, white muscle, liver, glandular stomach, muscular stomach, anterior intestine, pyloric cecum, spiral valve and rectum. The transcriptomes for each tissue were sequenced and assembled individually from a mean of 98.3 million (±38.9 million SD) reads each. In addition, an overall transcriptome was assembled and annotated with all data used for each tissue-specific transcriptome. All assembled transcriptomes and their annotations were made publicly available as a scientific resource. The non-gut transcriptomes provide important resources for many research avenues. However, we focused our analysis on messenger ribonucleic acid (mRNA) observations in the gut because the gut represents a compartmentalized organ system with compartmentalized functions, and seven of the sequenced tissues were from each of these portions. These gut-specific analyses were used to probe evidence of microbiome regulation by studying heterogeneity in microbial genes and genera identified from mRNA annotations. Gene set enrichment analyses were used to reveal the presence of photoperiod and circadian-related transcripts in the pyloric cecum, which may support periodicity in lake sturgeon digestion. Similar analyses were used to identify different types of innate immune regulation across the gut, while analyses of unique transcripts annotated to microbes revealed heterogeneous genera and genes among different gut tissues. The present results provide a scientific resource and information about the mechanisms of compartmentalized function across gut tissues in a phylogenetically ancient vertebrate.

Database URL: https://figshare.com/projects/Lake_Sturgeon_Transcriptomes/133143
Correlates and prognostic implications of LVEF reduction after transcatheter edge-to-edge repair for primary mitral regurgitation
Authors: Shechter Alon , Kaewkes Danon , Lee Mirae , Makar Moody , Patel Vivek , Koren Ofir , Koseki Keita , Nagasaka Takashi , Skaf Sabah , Chakravarty Tarun , Makkar Raj R , Siegel Robert J
Published: August 2023

Aims

To explore the characteristics and outcomes of patients undergoing transcatheter edge-to-edge repair (TEER) for primary mitral regurgitation (MR) according to the presence of left ventricular ejection fraction (LVEF) reduction post-procedure.

Methods and results

We retrospectively analysed 317 individuals [median age 83 (interquartile range, 75–88) years, 197 (62.1%) males] treated with an isolated, first-time TEER that was concluded by a successful clip deployment. Stratified by LVEF change at 1-month compared with baseline, the cohort was evaluated for residual MR and heart failure (HF) indices up to 1-year, as well as all-cause mortality and HF hospitalizations at 2-years. Overall, 212 (66.9%) patients displayed LVEF reduction, which was mainly driven by lowered total stroke volume and diffuse hypocontractility. While post-procedural MR, transmitral mean pressure gradient, and functional status were comparable in the two study groups, patients with LVEF reduction exhibited a greater decline in filling pressures intra-procedurally; left ventricular mass index, pulmonary arterial systolic pressure, and serum natriuretic peptide level at 1-month; and walking limitation at 1-year. Also, by 2 years, they were less likely to die (13.3% vs. 5.7%, P = 0.019), be readmitted for HF (17.1% vs. 9.0%, P = 0.033), and experience either of the two (23.8% vs. 12.7%, P = 0.012). Lastly, LVEF reduction was the only 1-month echocardiographic parameter to independently confer an attenuated risk for the composite of deaths or HF hospitalizations (HR 0.28, 95% CI 0.10–0.78, P = 0.016).

Conclusion

LVEF reduction at 1-month post-TEER for primary MR is associated with better clinical outcomes, possibly reflecting a more pronounced unloading effect of the procedure.
Transcatheter recanalization of chronic total occlusion in congenital heart disease: case reports and lessons from percutaneous coronary interventions
Authors: Hribernik Ines , Bentham James
Published: August 2023

Background

Chronic complete vascular occlusion causes significant morbidity and mortality in patients with congenital heart disease (CHD). The diversity of lesions, lack of dedicated equipment, and small number of procedures performed by individual operator continue to pose a challenge to congenital interventional cardiologists.

Case summary

We report two cases of percutaneous recanalization in CHD using percutaneous coronary intervention (PCI) equipment for chronic total occlusion (CTO).

Discussion

Careful pre-procedural planning, access site choice, use of catheter guiding systems for support, and selection of penetrating guidewires and techniques used in CTO-PCIs are key steps to a successful outcome.
The dose-dependent effect of estrogen on bone mineral density in trans girls
Authors: Boogers Lidewij Sophia , van der Loos Maria Anna Theodora Catharina , Wiepjes Chantal Maria , van Trotsenburg Adrianus Sarinus Paulus , den Heijer Martin , Hannema Sabine Elisabeth
Published: August 2023

Objective

Treatment in transgender girls can consist of puberty suppression (PS) with a gonadotropin-releasing hormone agonist (GnRHa) followed by gender-affirming hormonal treatment (GAHT) with estrogen. Bone mineral density (BMD) Z-scores decrease during PS and remain relatively low during GAHT, possibly due to insufficient estradiol dosage. Some adolescents receive high-dose estradiol or ethinyl estradiol (EE) to limit growth allowing comparison of BMD outcomes with different dosages.

Design

Retrospective study.

Methods

Adolescents treated with GnRHa for ≥1 year prior to GAHT followed by treatment with a regular estradiol dose (gradually increased to 2 mg), 6 mg estradiol or 100-200 µg EE were included to evaluate height-adjusted BMD Z-scores (HAZ scores) on DXA.

Results

Eighty-seven adolescents were included. During 2.3 ± 0.7 years PS, lumbar spine HAZ scores decreased by 0.69 [95% confidence interval (CI) −0.82 to −0.56)]. During 2 years HT, lumbar spine HAZ scores hardly increased in the regular group (0.14, 95% CI −0.01 to 0.28, n = 59) vs 0.42 (95% CI 0.13 to 0.72) in the 6 mg group (n = 13), and 0.68 (95% CI 0.20 to 1.15) in the EE group (n = 15). Compared with the regular group, the increase with EE treatment was higher (0.54, 95% CI 0.05 to 1.04). After 2 years HT, HAZ scores approached baseline levels at start of PS in individuals treated with 6 mg or EE (difference in 6 mg group −0.20, 95% CI −0.50 to 0.09; in EE 0.17, 95% CI −0.16 to 0.50) but not in the regular group (−0.64, 95% CI −0.79 to −0.49).

Conclusion

Higher estrogen dosage is associated with a greater increase in lumbar spine BMD Z-scores. Increasing dosage up to 2 mg estradiol is insufficient to optimize BMD and approximately 4 mg may be required for adequate serum concentrations.
Spatial methods for measuring access to health care
Authors: Beks Hannah , Wood Sarah M , Clark Robyn A , Vincent Versace L
Published: August 2023

Access to health care is a universal human right and key indicator of health system performance. Spatial access encompasses geographic factors mediating with the accessibility and availability of health services. Equity of health service access is a global issue, which includes access to the specialized nursing workforce. Nursing research applying spatial methods is in its infancy. Given the use of spatial methods in health research is a rapidly developing field, it is timely to provide guidance to inspire greater application in cardiovascular research. Therefore, the objective of this methods paper is to provide an overview of spatial analysis methods to measure the accessibility and availability of health services, when to consider applying spatial methods, and steps to consider for application in cardiovascular nursing research.
Lessons learned to boost a bioinformatics knowledge base reusability, the Bgee experience
Authors: Mendes de Farias Tarcisio , Wollbrett Julien , Robinson-Rechavi Marc , Bastian Frederic
Published: August 2023

Background

Enhancing interoperability of bioinformatics knowledge bases is a high-priority requirement to maximize data reusability and thus increase their utility such as the return on investment for biomedical research. A knowledge base may provide useful information for life scientists and other knowledge bases, but it only acquires exchange value once the knowledge base is (re)used, and without interoperability, the utility lies dormant.

Results

In this article, we discuss several approaches to boost interoperability depending on the interoperable parts. The findings are driven by several real-world scenario examples that were mostly implemented by Bgee, a well-established gene expression knowledge base. To better justify the findings are transferable, for each Bgee interoperability experience, we also highlight similar implementations by major bioinformatics knowledge bases. Moreover, we discuss ten general main lessons learned. These lessons can be applied in the context of any bioinformatics knowledge base to foster data reusability.

Conclusions

This work provides pragmatic methods and transferable skills to promote reusability of bioinformatics knowledge bases by focusing on interoperability.
Chromosome-level genome and recombination map of the male buffalo
Authors: Wang Xiaobo , Li Zhipeng , Feng Tong , Luo Xier , Xue Lintao , Mao Chonghui , Cui Kuiqing , Li Hui , Huang Jieping , Huang Kongwei , Rehman Saif-ur , Shi Deshun , Wu Dongdong , Ruan Jue , Liu Qingyou
Published: August 2023

Background

The swamp buffalo (Bubalus bubalis carabanesis) is an economically important livestock supplying milk, meat, leather, and draft power. Several female buffalo genomes have been available, but the lack of high-quality male genomes hinders studies on chromosome evolution, especially Y, as well as meiotic recombination.

Results

Here, a chromosome-level genome with a contig N50 of 72.2 Mb and a fine-scale recombination map of male buffalo were reported. We found that transposable elements (TEs) and structural variants (SVs) may contribute to buffalo evolution by influencing adjacent gene expression. We further found that the pseudoautosomal region (PAR) of the Y chromosome is subject to stronger purification selection. The meiotic recombination map showed that there were 2 obvious recombination hotspots on chromosome 8, and the genes around them were mainly related to tooth development, which may have helped to enhance the adaption of buffalo to inferior feed. Among several genomic features, TE density has the strongest correlation with recombination rates. Moreover, the TE subfamily, SINE/tRNA, is likely to play a role in driving recombination into SVs.

Conclusions

The male genome and sperm sequencing will facilitate the understanding of the buffalo genomic evolution and functional research.