bluuebunny/crossref_metadata_2025 huggingface dataset:
Strategic pathways to sustainable energy: Carbon emission pinch analysis for Bangladesh's electricity sector
Authors: Tarequzzaman Md. , Khan Imran , Sahabuddin Md. , Al-Amin Md.
Published: April 2024

Balancing burgeoning energy demands in the electricity sector while curbing carbon emissions poses a formidable challenge for emerging economies like Bangladesh, which is heavily reliant on fossil fuels. Despite the country's power system master plan (PSMP) until 2041 and submitted intended nationally determined contributions (INDC) to tackle mounting energy needs and associated emissions, the PSMP lacks specific emission reduction strategies. Thus, this study employs carbon emission pinch analysis to facilitate Bangladesh's long-term energy planning, highlighting emission reduction hurdles. This research aims to set emission limits, delineate fossil fuel and carbon-neutral source (i.e., zero emission during operation) compositions, ascertain carbon-neutral source ranges for targeted emissions, and propose viable carbon-neutral sources to meet escalating energy demands. Three scenarios are extensively explored: fulfilling INDC mandates, a 10% increase in renewable energy, and maintaining 2035 emission levels in 2040. The analysis unveils emission limits of 55 758.83 and 84 778.61 × 109 grams of CO2 equivalent for 2025 and 2030, respectively. Projections indicate a foreseen 10% surge in renewable energy by 2035, elevating its share to 18.16%. Carbon-neutral energy sources, encompassing solar, wind, hydroelectricity, biomass, and nuclear, are estimated to cover 56.06% of energy demand by 2040, driving a 33.30% emissions reduction.
Attractive crowding effect on passive and active polymer looping kinetics
Authors: Yan Ran , Zhao Chaonan , Zhao Nanrong
Published: April 2024

Loop formation in complex environments is crucially important to many biological processes in life. In the present work, we adopt three-dimensional Langevin dynamics simulations to investigate passive and active polymer looping kinetics in crowded media featuring polymer–crowder attraction. We find polymers undergo a remarkable coil–globule–coil transition, highlighted by a marked change in the Flory scaling exponent of the gyration radius. Meanwhile, looping time as a function of the crowder’s volume fraction demonstrates an apparent non-monotonic alteration. A small number of crowders induce a compact structure, which largely facilitates the looping process. While a large number of crowders heavily impede end-to-end diffusion, looping kinetics is greatly inhibited. For a self-propelled chain, we find that the attractive crowding triggers an unusual activity effect on looping kinetics. Once a globular state is formed, activity takes an effort to open the chain from the compact structure, leading to an unexpected activity-induced inhibition of looping. If the chain maintains a coil state, the dominant role of activity is to enhance diffusivity and, thus, speed up looping kinetics. The novel conformational change and looping kinetics of both passive and active polymers in the presence of attractive crowding highlight a rather distinct scenario that has no analogy in a repulsive crowding counterpart. The underlying mechanism enriches our understanding of the crucial role of attractive interactions in modulating polymer structure and dynamics.
A few-shot based phase-batch multi-layer domain adaptation pattern recognition method
Authors: Li Yiming , Wang Jiankang , Luo Guangxu , Liu TongShan , Song Guiqiu
Published: April 2024

Deep transfer learning has been widely applied in the field of intelligent fault diagnosis. However, existing deep transfer learning-based diagnostic methods struggle to train reliable diagnostic models when there is a lack of data and significant distribution differences between the two domains. To address this issue, a few-shot based phase-batch multi-layer domain adaptation pattern recognition method is proposed. This method simultaneously measures the feature distribution differences of both the fully connected layers and the classification layers, thus better correcting the data domain bias. Additionally, a phase-batch training strategy and pseudo-label learning are employed to improve the convergence speed and stability of the training process. The proposed method is validated on two public datasets, Jiang Nan and Paderborn University, as well as a dataset obtained through independent experiments. It is compared with traditional feature-based transfer learning methods, the results show that the proposed method achieves higher diagnostic accuracy, faster convergence, and greater stability. Furthermore, its superior diagnostic performance in the few-shot scenario is demonstrated through experiments on a self-collected dataset.
Development of a high precision electrostatic force balance for measuring quantity of dispensed fluid as a new calibration standard for the becquerel
Authors: Schulze Sven , Arumugam Kumar , Schlamminger Stephan , Fitzgerald Ryan , Verkouteren R Michael , Theska René , Shaw Gordon
Published: April 2024

The 2019 redefinition of the kilogram not only changes the way mass is defined but also broadens the horizon for a direct realization of other standards. The true becquerel project at the national institute of standards and technology is creating a new paradigm for realization and dissemination of radionuclide activity. Standard reference materials for radioactivity are supplied as aqueous solutions of specific radionuclides which are characterized by massic activity in the units becquerel per gram of solution, Bq/g. The new method requires measuring the mass of a few milligrams of dispensed radionuclide liquid solution. An electrostatic force balance is used, due to its suitability for a milligram mass range. The goal is to measure the mass of dispensed fluid of 1 mg–5 mg with a relative uncertainty of less than 0.05%. A description of the balance operation is presented. Results of preliminary measurements with a reference mass indicate relative standard deviations less than 0.5% for tens of tests and differ 0.54% or less from an independent measurement of the reference mass.
Intelligent fault diagnosis of rolling bearings under small samples based on lightweight UNet with attention-fused residual block
Authors: Sun Xiaochun , Ding Hua , Li Ning , Dong Xiaoxin , Liao Yaoyao , Liu Zeping , Bai Xin
Published: April 2024

In rotating machinery, rolling bearings are crucial, and their failure can lead to severe accidents and economic losses. Therefore, fault diagnosis of bearings is necessary to maintain the safe and stable operation of modern machinery and equipment. Currently, data-driven intelligent diagnosis methods are mainstream; however, in practical applications, problems such as insufficient fault samples and strong interference signals often exist. At the same time, a large number of edge-end and mobile devices put higher requirements for the size of the diagnostic model. This study addresses these issues by proposing a lightweight UNet (LWUNet) model, which integrates wavelet packet decomposition (WPD) and attention-fused residual block (AFRB) for fault diagnosis in rolling bearings under varying operating conditions, particularly for small sample sizes. Firstly, WPD is used to decompose and reconstruct the fault signal to achieve effective denoising. Secondly, a LW-UNet is constructed for pixel-level feature learning to reduce the number of parameters and improve the accuracy rate. Thereafter, to further enhance the model feature extraction capability, the AFRB is proposed and embedded into the LWUNet to develop the AFRB-LWUNet model. Finally, the reconstructed signals are input to the proposed model for training, and the model performance is examined using a test set. The proposed method is compared with other fault diagnosis models using small sample data of rolling bearings from the Case Western Reserve University, USA and the University of Paderborn, Germany. The results confirm the higher recognition accuracy, stronger generalization ability, and robustness of the proposed method for small samples under various working conditions and intense noise.
The effect of geometrical parameters on dimensional deviation in LPBF produced TPMS lattices: a numerical simulation based study
Authors: Gülcan Orhan , Günaydın Kadir , Tamer Aykut
Published: April 2024

Triply periodic minimal surface (TPMS) lattices have drawn great attention both in academic and industrial perspective due to their outstanding mechanical behaviours. Additive manufacturing (AM) modalities enable the production of these lattices very easily. However, dimensional inaccuracy is still one of the problems that AM still faces with. Manufacturing of these lattices with AM modalities, then measuring the critical dimensions and making design changes accordingly is a costly process. Therefore, it is necessary to predict the dimensional deviation of TPMS lattices before print is a key topic. This study focused on prediction of dimensional deviation of laser powder bed fusion (LPBF) produced gyroid, diamond, primitive, IWP and Fisher-Koch lattices by using thermomechanical simulations. TPMS type, unit cell size, volume fraction, functional grading and part orientation were selected as design variables. Results showed that all the design inputs have effects on dimensional accuracy of LPBF produced parts and TPMS type has the most critical factor. Based on analysis of variance analysis, an optimum lattice configuration was proposed to obtain the lowest dimensional deviation after LPBF build.
Invariant measures for random piecewise convex maps
Authors: Inoue Tomoki , Toyokawa Hisayoshi
Published: April 2024

We establish the existence of Lebesgue-equivalent conservative and ergodic

σ

-finite invariant measures for a wide class of one-dimensional random maps consisting of piecewise convex maps. We also estimate the size of invariant measures around a small neighbourhood of a fixed point where the invariant density functions may diverge. Application covers random intermittent maps with critical points or flat points. We also illustrate that the size of invariant measures tends to infinite for random maps whose right branches exhibit a strongly contracting property on average, so that they have a strong recurrence to a fixed point.
Evaluation of calibrated and uncalibrated optical imaging approaches for relative cerebral oxygen metabolism measurements in awake mice
Authors: Toader A E , Fukuda M , Vazquez A L
Published: April 2024

Objective. The continuous delivery of oxygen is critical to sustain brain function, and therefore, measuring brain oxygen consumption can provide vital physiological insight. In this work, we examine the impact of calibration and cerebral blood flow (CBF) measurements on the computation of the relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2) from hemoglobin-sensitive intrinsic optical imaging data. Using these data, we calculate rCMRO2, and calibrate the model using an isometabolic stimulus. Approach. We used awake head-fixed rodents to obtain hemoglobin-sensitive optical imaging data to test different calibrated and uncalibrated rCMRO2 models. Hypercapnia was used for calibration and whisker stimulation was used to test the impact of calibration. Main results. We found that typical uncalibrated models can provide reasonable estimates of rCMRO2 with differences as small as 7%–9% compared to their calibrated models. However, calibrated models showed lower variability and less dependence on baseline hemoglobin concentrations. Lastly, we found that supplying the model with measurements of CBF significantly reduced error and variability in rCMRO2 change calculations. Significance. The effect of calibration on rCMRO2 calculations remains understudied, and we systematically evaluated different rCMRO2 calculation scenarios that consider including different measurement combinations. This study provides a quantitative comparison of these scenarios to evaluate trade-offs that can be vital to the design of blood oxygenation sensitive imaging experiments for rCMRO2 calculation.
Octupole deformation in two-quasiparticle states of even–even deformed nuclei
Authors: Bonneau L , Kontowicz N , Minkov N , Koh Meng-Hock
Published: April 2024

Following the Skyrme-Hartree–Fock-BCS approach with blocking to two-quasiparticle states describing K-isomeric states of deformed even–even nuclei as presented in an earlier work of some of us Minkov N et al (2022 Phys. Rev. C
105 044 329), we study the emergence of axial-octupole deformation in excited states of this nature. We select two representative nuclei in the rare-earth and actinide mass regions, namely 148Ce (octupole-deformed in its ground state) and 234U (with a left-right symmetric ground-state shape), and several low-lying two-quasiparticle configurations illustrating cases where, in the same nucleus, some such excited states are calculated to be octupole deformed and some others are not. Then we investigate the mechanism favoring the appearance of left-right asymmetric shapes in the two-quasiparticle excited states of one-particle-one-hole type. We find in particular that strong octupole coupling between the blocked hole and particle states of a two-quasiparticle configuration does not favor pear-like shapes. In contrast, octupole coupling of the blocked particle (resp. hole) state with another particle (resp. hole) state located slightly above (resp. below) it in the single-particle spectrum favors pear-like shapes in the two-quasiparticle state.
Insights and potentials of two-dimensional black phosphorous-based solar cells
Authors: Thirugnanasambandan Theivasanthi , Karuppaiah Chinnaiah , Sankar Balaguru Venkatesh , Gopinath Subash C B
Published: April 2024

The development of advanced materials, new device architectures and fabrication processes will lead to more utilization of renewable energy sources like solar energy. Solar energy can be harvested more effectively using solar cells incorporated with advanced nanomaterials. Black phosphorus (BP) is a two-dimensional material in which the layers are stacked together through van der Waals forces. The electrical and optical properties of the material are much more suitable for use in solar cell applications. BP nanosheets have optoelectronic properties such as tunable bandgap (0.3 eV − 2.0 eV) and high carrier mobility that make them as suitable candidates for solar cells. Also, BP is able to absorb a wide range of light energy in the electromagnetic spectrum. Being a p-type semiconductor, BP finds applications in optoelectronic and semiconductor- devices. The optical absorption of the material is determined by its structural orientation. The material also possesses the high in-plane anisotropic band dispersion near the Fermi level in the Brillouin zone which results in a high direction-dependent optical and electronic properties. The major limitation of the material is its stability since it is degraded under the illumination of light. BP is used as an electron transport layer in solar cells similar to ZnO, TiO2 and graphene. BP can also be integrated with hole transport layers and active materials. Research efforts have shown that BP and its derivatives have more potential to produce high efficiency solar cells. The application of BP in various solar cells and the enhancement in the efficiency of solar cells such as organic solar cells, perovskite solar cells, dye-sensitized solar cells and silicon solar cells are discussed in this review.
The qualitative properties of 1D mixed-type Potts-SOS model with 1-spin and its dynamical behavior
Authors: Akın Hasan
Published: April 2024

In this investigation, we consider the one-dimensional (1D) mixed-type Potts-SOS model, where the spin is within the range of {−1, 0, 1}. We elaborate thermodynamic characteristics of 1D Potts-SOS model through the application of three distinct analytical approaches. We provide a brief overview of all translation-invariant splitting Gibbs measures (TISGMs) applicable to this model. For the model with a boundary field condition, we provide a comprehensive analysis of the uniqueness and non-uniqueness properties of the subset of fully homogeneous splitting Gibbs masures (SGMs). Our demonstration reveals that the model under consideration does not exhibit a phase transition phenomenon. We are also curious in the stability study of the suggested fixed points associated with the Gibbs measures. We show that the magnetization decreases to zero. By means of the transfer matrix method, we compute the free energy, entropy and internal energy of the model.
Microwave-assisted green synthesis of silver nanoparticles using turnip root (Brassica rapa subsp. Rapa) extract and their antibacterial efficacy
Authors: Alazzawi Ali H , Al-Tamimi Basma H , S Abed Mayyadah
Published: April 2024

Biosynthesised silver nanoparticles (AgNPs), especially those synthesised by plant extracts, are extensively utilised in the fields of pharmacy and medicine due to their ability to exhibit a wide range of biological functions. The current study is focused on the green synthesis of silver nanoparticles from various concentrated silver nitrate solutions using turnip root extract as a reducing and stabilising agent and to assess the in vitro antibacterial efficacy of these AgNPs. For the study, we employed microwave-assisted reduction to examine the impact of microwave energy on the resulting AgNPs in comparison to the conventional heating method. X-ray diffraction analysis revealed the crystalline nature of the as-prepared AgNPs, while field emission-scanning electron microscopy (FE-SEM) showed the majority of spherical-shaped AgNPs had an average grain size of 47.5 nm. Energy-dispersive x-ray spectroscopy (EDX) indicates the high weight percentage of the produced AgNPs than for extract residue, especially for the AgNPs that are prepared with microwave assistance. Fourier transform infrared spectroscopy (FTIR) was used to reveal the functional groups that are related to many phytochemical compounds, such as alkaloids, flavonoids, and terpenoids, which act as reducing and stabilizing agents. High zeta potential measures (−22.77 and −38.83 mv) approved the high stability of the synthesised AgNPs as higher zeta potentials typically correlate with greater stability. The antibacterial activity behaviour of the produced NPs against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria was significantly acceptable for both heating techniques, as observed from the measured inhibition zone.
Electronic states in GaAs/AlGaAs/GaAs core/shell cylindrical quantum wires
Authors: Qasem M R , Machichi S , Touiss T , Falyouni F , Bria D
Published: April 2024

Cylindrical quantum wires (CQWRs) based on GaAs/

Al

x

B

Ga

1
−

x

B

As

/GaAs core/shell semiconductors are multilayer semiconductor nanostructures that exhibit interesting electronic properties. In this study, we explore in detail the electronic band structure and electronic transmission spectrum in these core/shell CQWRs in relation to various parameters such as inner and outer shell radius and aluminum-doping rate. Using Green’s function formalism, an advanced theoretical approach to solving Schrödinger’s equation in the effective mass approximation, taking into account the confinement potential of the cylindrical geometry. The results show that as the difference between the outer and inner radii of the shell increases, the number of electronic states increases due to the weakening of geometric confinement. In addition, as the concentration of Aluminum in the shell increases, the electronic states move to higher energies, due to the increase in confinement by the height of the potential. This study aims to provide an overview of the electronic states in core/shell nanowires, due to modification in Al molar concentration and shell size; they offer advantages such as better electronic transmission. We can control the electronic band structure of this nanowire, which can be used to fabricate high-performance electronic devices such as transistors, diodes and sensors.
Translocation of polymers through a wide-open conical pore
Authors: Sharma Andri
Published: April 2024

The transport of biomolecules across a cell membrane is an important phenomenon that plays a pivotal role in the functioning of biological cells. In this paper, we investigate such processes by modeling the translocation of polymers through a conical channel, directed from the wider opening to the narrow end of the conical channel. We use the molecular dynamics approach to study the problem. The effect of the different conical pore geometry and polymer lengths on translocation dynamics is determined from the behavior of the total translocation time, τ, and the waiting time distributions, w(s). The escape of polymer segments from the narrow end of the conical channel is tracked by studying the escape velocity profile (〈v

i
〉). To demonstrate the asymmetric pore effects on the translocation dynamics, we compare the translocation process from both the terminals: the wider-opening and the narrow-end of the conical channel. We find striking differences in the translocation dynamics for both processes, which are in agreement with the experimental study. We have accounted for the effect of various rigidity, and increasing length of a polymer chain, on both types of processes. This computational study can be used to underline the translocation process from different conical pores.
Short-range-order degree dominated physical and mechanical properties of refractory multi-principal element alloys: a first-principles study
Authors: Yu Libo , Li Jia , Liaw Peter K , Fang Qihong
Published: April 2024

The degree of short-range order (SRO) can influence the physical and mechanical properties of refractory multi-principal element alloys (RMPEAs). Here, the effect of SRO degree on the atomic configuration and properties of the equiatomic TiTaZr RMPEA is investigated using the first-principles calculations. Their key roles on the lattice parameters, binding energy, elastic properties, electronic structure, and stacking fault energy (SFE) are analyzed. The results show the degree of SRO has a significant effect on the physical and mechanical properties of TiTaZr. During the SRO degree increasing in TiTaZr lattice, the low SRO degree exacerbates the lattice distortion and the high SRO degree reduces the lattice distortion. The high degree of SRO improves the binding energy and elastic stiffness of the TiTaZr. By analyzing the change in charge density, this change is caused by the atomic bias generated during the formation of the SRO, which leading to a change in charge-density thereby affecting the metal bond polarity and inter-atomic forces. The high SRO degree also reduces SFE, which means the capability of plastic deformation of the TiTaZr is enhanced.
Induced gravitational waves from non-attractor inflation and NANOGrav data
Authors: Nassiri-Rad Amin , Asadi Kosar
Published: April 2024

In this paper, we investigate the scalar-induced gravitational waves in single-field non-attractor inflation for the Pulsar Timing Arrays data. Our model comprises three phases of inflation: the first and third phases are slow-roll inflation, while the second phase is a period of non-attractor inflation. We analyze the model's predictions for various values of the sound speed cs
and examine the sharp transitions to the final attractor phase. Furthermore, we study the model's predictions for NANOGrav observations and future gravitational wave observations. We also calculate the non-Gaussianity parameter fNL
for the non-attractor setup with a general sound speed and the sharpness parameter.
A stacked search for spatial coincidences between IceCube neutrinos and radio pulsars
Authors: Pasumarti Vibhavasu , Desai Shantanu
Published: April 2024

We carry out a stacked search for spatial coincidences between all the known radio pulsars
and TeV neutrinos from the IceCube 10 year (2008–2018) muon track data, as a followup to our
previous work on searching for spatial coincidences with individual pulsars. We consider three
different weighting schemes to stack the contributions from each pulsar. We do not find a
statistically significant excess using this method. We report the 95% c.l. neutrino flux upper
limit as a function of the neutrino energy. We have also made our analysis codes
publicly available.
Effect of distribution shape on the melting transition, local ordering, and dynamics in a model size-polydisperse two-dimensional fluid
Authors: Pame Jackson , Shagolsem Lenin S.
Published: April 2024

We study the effect of particle size polydispersity (δ) on the melting transition (T
*), local ordering, solid–liquid coexistence phase and dynamics of two-dimensional Lennard–Jones fluids up to moderate polydispersity by means of computer simulations. The particle sizes are drawn at random from the Gaussian (G) and uniform (U) distribution functions. For these systems, we further consider two different kinds of particles, viz., particles having the same mass irrespective of size, and in the other case the mass of the particle scales with its size. It is observed that with increasing polydispersity, the value of T
* initially increases due to improved packing efficiency (ϕ) followed by a decrease and terminates at δ ≈ 8% (U-system) and 14% (G-system) with no significant difference for both mass types. The interesting observation is that the particular value at which ϕ drops suddenly coincides with the peak of the heat capacity (CP
) curve, indicating a transition. The quantification of local particle ordering through the hexatic order parameter (Q
6), Voronoi construction and pair correlation function reveals that the ordering decreases with increasing δ and T. Furthermore, the solid–liquid coexistence region for the G-system is shown to be comparatively wider in the T–δ plane phase diagram than that for the U system. Finally, the study of dynamics reveals that polydisperse systems relax faster compared to monodisperse systems; however, no significant qualitative differences, depending on the distribution type and mass polydispersity, are observed.
Anisotropic metal–insulator transition in strained VO2(B) single crystal
Authors: Ma 马 Zecheng 泽成 , Yan 闫 Shengnan 胜楠 , Liu 刘 Zenglin 增霖 , Xu 徐 Tao 涛 , Chen 陈 Fanqiang 繁强 , Chen 陈 Sicheng 思成 , Cao 曹 Tianjun 天俊 , Sun 孙 Litao 立涛 , Cheng 程 Bin 斌 , Liang 梁 Shi-Jun 世军 , Miao 缪 Feng 峰
Published: April 2024

Mechanical strain can induce noteworthy structural and electronic changes in vanadium dioxide, imparting substantial scientific importance to both the exploration of phase transitions and the development of potential technological applications. Unlike the traditional rutile (R) phase, bronze-phase vanadium dioxide [VO2(B)] exhibits an in-plane anisotropic structure. When subjected to stretching along distinct crystallographic axes, VO2(B) may further manifest the axial dependence in lattice–electron interactions, which is beneficial for gaining insights into the anisotropy of electronic transport. Here, we report an anisotropic room-temperature metal–insulator transition in single-crystal VO2(B) by applying in-situ uniaxial tensile strain. This material exhibits significantly different electromechanical responses along two anisotropic axes. We reveal that such an anisotropic electromechanical response mainly arises from the preferential arrangement of a strain-induced unidirectional stripe state in the conductive channel. This insulating stripe state could be attributed to the in-plane dimerization within the distorted zigzag chains of vanadium atoms, evidenced by strain-modulated Raman spectra. Our work may open up a promising avenue for exploiting the anisotropy of metal–insulator transition in vanadium dioxide for potential technological applications.
Kinetic-ballooning-limited pedestals in spherical tokamak plasmas
Authors: Parisi J.F. , Guttenfelder W. , Nelson A.O. , Gaur R. , Kleiner A. , Lampert M. , Avdeeva G. , Berkery J.W. , Clauser C. , Curie M. , Diallo A. , Dorland W. , Kaye S.M. , McClenaghan J. , Parra F.I.
Published: April 2024

A theoretical model is presented that for the first time matches experimental measurements of the pedestal width-height Diallo scaling in the low-aspect-ratio high-β tokamak NSTX. Combining linear gyrokinetics with self-consistent pedestal equilibrium variation, kinetic-ballooning, rather than ideal-ballooning plasma instability, is shown to limit achievable confinement in spherical tokamak pedestals. Simulations are used to find the novel Gyrokinetic Critical Pedestal constraint, which determines the steepest pressure profile a pedestal can sustain subject to gyrokinetic instability. Gyrokinetic width-height scaling expressions for NSTX pedestals with varying density and temperature profiles are obtained. These scalings for STs depart significantly from that of conventional aspect ratio tokamaks.
Improving the properties of aluminum-lithium composites in aerospace applications: review
Authors: Polayya Ch , Rao C S P , Veeresh Kumar G B
Published: April 2024

Aluminium (Al)-Lithium (Li) alloys have found widespread applications in aerospace and military domains. Primarily, they are found to have low density, leading to weight savings and several economic considerations. The paper explores the historical development of Al-Li alloys across distinct generations, highlighting their evolution. It also delves into the diverse applications of Al-Li alloys in aerospace and military domains. A concise discussion of the mechanical behaviour and tensile strengths is presented across the first, second, and third generations of Al-Li alloys. This review includes a discussion on microstructural investigation, emphasizing metallurgical factors such as increased efficiency, various precipitate phases, and intergranular features. Weldability and tribological properties of Al-Li alloys, with a specific emphasis on the corrosion aspects of these alloys, are discussed. Furthermore, the review assesses the future development and manufacturing flexibility of Al-Li Metal Matrix Composites. In summary, this comprehensive review consolidates insights into the utilization, evolution, and characteristics of Al-Li Metal Matrix Composites, providing valuable information for researchers and practitioners aiming to enhance the performance of these alloys in aerospace applications.
Examining shifts in the Angola–China relations in the post-dos santos era
Authors: Jura Jarosław , Kopiński Dominik , Polus Andrzej , Tycholiz Wojciech
Published: April 2024

The Angola–China connection has famously been branded a ‘marriage of convenience’—an ‘uneasy alliance’ forged for pragmatic reasons at an opportune time of mutual need. In this article, we document how the relationship has more recently undergone a marital burnout of sorts. Chinese loans to Angola have dried up and most Chinese state-owned enterprises have left, as have 90 percent of Chinese migrants. The legacy of this marriage is somewhat mixed. Much of the infrastructure left behind is of dubious quality, while servicing the Chinese debt incurred to finance these projects may consume up to 10 percent of Angola’s GDP. Drawing on three rounds of fieldwork in Angola and over 60 interviews, we trace the souring of Angola–China ties to three concomitant factors: (i) Angolan internal politics; (ii) Chinese reconfiguration; and (iii) exogenous shifts in the global economy. In doing so, we argue that China and Angola are entering new territory, and that this shift in both parties’ calculations can be usefully illuminated by the concept of ‘strategies of extraversion’. Angola’s elites have once again proven that they are adept at transforming external constraints—this time related to China’s increasing financial caution and domestic recalibration—into new opportunities.
Sex differences in cognitive decline among middle-aged and older adults: a cohort study in Europe
Authors: Wolfova Katrin , Frycova Barbora , Seblova Dominika , Tom Sarah , Skirbekk Vegard Fykse , Brennan Kearns Pavla
Published: April 2024

Objectives

Previous studies on sex differences in cognitive decline provide inconsistent findings, with many European countries being underrepresented. We determined the association between sex and cognitive decline in a sample of Europeans and explored differences across birth cohorts and regions.

Methods

Participants 50+ years old enrolled in the Survey of Health, Ageing and Retirement in Europe had their cognition measured by tests of immediate recall, delayed recall and verbal fluency biennially up to 17 years of follow-up (median 6, interquartile range 3–9 years). We used linear mixed-effects models to assess the relationship between sex and the rate of cognitive decline, adjusting for sociodemographic and health-related characteristics.

Results

Of 66,670 participants (mean baseline age 63.5 ± standard deviation 9.4), 55% were female. Males and females had similar rates of decline in the whole sample in immediate recall (beta for interaction sex × time B = 0.002, 95% CI -0.001 to 0.006), delayed recall (B = 0.000, 95% CI −0.004 to 0.004), and verbal fluency (B = 0.008, 95% CI −0.005 to 0.020). Females born before World War II had a faster rate of decline in immediate recall and delayed recall compared to males, while females born during or after World War II had a slower rate of decline in immediate recall. Females in Central and Eastern Europe had a slower rate of cognitive decline in delayed recall compared to males.

Discussion

Our study does not provide strong evidence of sex differences in cognitive decline among older Europeans. However, we identified heterogeneity across birth cohorts and regions.
Intra-arterial delivery of neurospheres into isolated perfused porcine colons: a proof of concept
Authors: Martel Richard D , Hoyos Nicolas A , Tapia-Laliena María Ángeles , Herrmann Irmgard , Herrmann Martin , Khasanov Rasul , Schäfer Karl-Herbert
Published: April 2024

Cell replacement in aganglionic intestines is a promising, yet merely experimental tool for the therapy of congenital dysganglionosis of the enteric nervous system like Hirschsprung disease. While the injection of single cells or neurospheres to a defined and very restricted location is trivial, the translation to the clinical application, where large aganglionic or hypoganglionic areas need to be colonized (hundreds of square centimetres), afford a homogeneous distribution of multiple neurospheres all over the affected tissue areas. Reaching the entire aganglionic area in vivo is critical for the restoration of peristaltic function. The latter mainly depends on an intact nervous system that extends throughout the organ. Intra-arterial injection is a common method in cell therapy and may be the key to delivering cells or neurospheres into the capillary bed of the colon with area-wide distribution. We describe an experimental method for monitoring the distribution of a defined number of neurospheres into porcine recta ex vivo, immediately after intra-arterial injection. We designed this method to localize grafting sites of single neurospheres in precise biopsies which can further be examined in explant cultures. The isolated perfused porcine rectum allowed us to continuously monitor the perfusion pressure. A blockage of too many capillaries would lead to an ischaemic situation and an increase of perfusion pressure. Since we could demonstrate that the area-wide delivery of neurospheres did not alter the overall vascular resistance, we showed that the delivery does not significantly impair the local circulation.
Morphological and regional spontaneous functional aberrations in the brain associated with Crohn’s disease: a systematic review and coordinate-based meta-analyses
Authors: Kong Ning , Zhou Feini , Zhang Fan , Gao Chen , Wu Linyu , Guo Yifan , Gao Yiyuan , Lin Jiangnan , Xu Maosheng
Published: April 2024

Crohn's disease is an acknowledged “brain–gut” disorder with unclear physiopathology. This study aims to identify potential neuroimaging biomarkers of Crohn's disease. Gray matter volume, cortical thickness, amplitude of low-frequency fluctuations, and regional homogeneity were selected as indices of interest and subjected to analyses using both activation likelihood estimation and seed-based d mapping with permutation of subject images. In comparison to healthy controls, Crohn's disease patients in remission exhibited decreased gray matter volume in the medial frontal gyrus and concurrently increased regional homogeneity. Furthermore, gray matter volume reduction in the medial superior frontal gyrus and anterior cingulate/paracingulate gyri, decreased regional homogeneity in the median cingulate/paracingulate gyri, superior frontal gyrus, paracentral lobule, and insula were observed. The gray matter changes of medial frontal gyrus were confirmed through both methods: decreased gray matter volume of medial frontal gyrus and medial superior frontal gyrus were identified by activation likelihood estimation and seed-based d mapping with permutation of subject images, respectively. The meta-regression analyses showed a positive correlation between regional homogeneity alterations and patient age in the supplementary motor area and a negative correlation between gray matter volume changes and patients’ anxiety scores in the medial superior frontal gyrus. These anomalies may be associated with clinical manifestations including abdominal pain, psychiatric disorders, and possibly reflective of compensatory mechanisms.
Cortical specialization associated with native speech category acquisition in early infancy
Authors: Ren Jie , Cai Lin , Jia Gaoding , Niu Haijing
Published: April 2024

This study investigates neural processes in infant speech processing, with a focus on left frontal brain regions and hemispheric lateralization in Mandarin-speaking infants' acquisition of native tonal categories. We tested 2- to 6-month-old Mandarin learners to explore age-related improvements in tone discrimination, the role of inferior frontal regions in abstract speech category representation, and left hemisphere lateralization during tone processing. Using a block design, we presented four Mandarin tones via [ta] and measured oxygenated hemoglobin concentration with functional near-infrared spectroscopy. Results showed age-related improvements in tone discrimination, greater involvement of frontal regions in older infants indicating abstract tonal representation development and increased bilateral activation mirroring native adult Mandarin speakers. These findings contribute to our broader understanding of the relationship between native speech acquisition and infant brain development during the critical period of early language learning.
Immune stress and diet influence reproductive fitness in male tuatara (Sphenodon punctatus)
Authors: Lamar Sarah K , Ormsby Diane K , Nelson Nicola J
Published: April 2024

The theoretical trade-off between immune and endocrine investment in mating animals has received mixed empirical support, particularly in reptiles. We investigated the relationship between male sexual characteristics, diet, and immune response to stress in an island population of tuatara (Sphenodon punctatus) across two mating seasons. Tuatara are promiscuous, with a highly skewed mating system where males face significant competition for access to mates and postcopulatory competition for fertilization success. We found that tuatara sperm viability and swim speed were negatively associated with male body condition and the ratio of heterophils to lymphocytes. Additionally, sperm swim speed was negatively associated with spine area, mite load, and the total number of circulating white blood cells, but was positively associated with tick number. This is likely a function of social dynamics in this system where larger male size predicts greater spatial overlap with potential rivals and increased tick load. Because the production of sexual characteristics may be costly, we also investigated the effect of diet on sperm quality. We did not identify an association between diet and sperm viability. However, sperm swim speed was negatively associated with carbon-13 and positively associated with nitrogen-15. We suspect that these results reflect the influence of seabird-based nutrients in this island ecosystem, particularly polyunsaturated fatty acid, and antioxidant damage on tuatara sperm. In total, these results provide evidence of a trade-off between pre- and post-copulatory sexual characteristics and the immune and endocrine systems in male tuatara.
Chronic effect of copper on biology, immunity, and biochemical assessment of Helicoverpa armigera (Lepidoptera; Noctuidae) in laboratory bioassays
Authors: Azizi Roya , Sendi Jalal Jalali
Published: April 2024

Although copper is an essential element for any organism’s well-being, it becomes toxic if present in excess. In the present study, copper was provisioned at 25, 50, and 75 mg/kg in an artificial diet and fed to juvenile larvae of cotton bollworm, Helicoverpa armigera (Lepidoptera; Noctuidae), for 4 generations. The results of this investigation exhibited shortening of larval life in the first 2 generations, but extended duration was observed in third and fourth generations compared to controls, and dietary copper caused reduced total hemocyte counts in all treatments. The number of immunocytes (i.e., granulocytes and plasmatocytes) were also significantly reduced. The changes in activities of certain important enzymes, including catalase, superoxide dismutase, and peroxidases, were seen. Furthermore, after treatment, an increase in the activity of 2 detoxifying enzymes, glutathione s-transferase and acetylcholinesterase, was observed. It is clear that metallothioneins are important in maintaining essential and nonessential metal ion homeostasis. While copper is typically regarded as an important essential metal in an organism’s life, excessive amounts can have deteriorating effects. This heavy metal is being used as a nano-based pesticide. Therefore, the present investigation aims to determine the fate of Cu in insects receiving them in new formulations.
Case report: desmoplakin cardiomyopathy presenting as an inflammatory cardiomyopathy with repeated sudden cardiac arrests
Authors: Massie Emmanuelle , Dominati Arnaud , Suchet Sebastian , Carballo David , Hervier Elsa , Fokstuen Siv , Seebach Jöerg D , Meyer Philippe
Published: April 2024

Background

Desmoplakin cardiomyopathy has been recently classified as a non-dilated left ventricular cardiomyopathy, which is characterized by inflammatory-like episodes followed by left ventricular fibrosis/dysfunction and ventricular arrhythmias. Specific management is unclear.

Case summary

We report a detailed case of a 46-year-old Caucasian woman presenting with repeated sudden cardiac arrests who was diagnosed with a new variant in the desmoplakin gene. Because the initial 18F-fluorodeoxyglucose positron emission tomography scan showed significant hypermetabolism, she was treated with immunosuppressors, with only minimal improvement on imaging.

Discussion

Desmoplakin cardiomyopathy should be considered in the differential diagnosis of inflammatory cardiomyopathies. Little is known about the use of immunosuppressive treatments, but it could be reasonable for some selected patients.
Food safety
Authors: Rodricks Joseph V. , Hulebak Karen , Cush Meera
Published: April 2024

This chapter focuses on the importance of food safety and its corresponding major threats. The science of food safety is devoted to understanding how substances present in food may have adverse effects on health. The programmes used to protect human health are developed and implemented within a process called risk management, while the identification of safe exposures is run through risk assessment. The chapter looks into the international risk management programme of the Codex Alimentarius Commission (CAC), its supporting scientific structures, and its relationship to the risk management agencies of its member nations. It clarifies that food safety is concerned with individual constituents and contaminants of food, instead of diets as a whole.
Carbohydrate metabolism
Authors: Brameld John M. , Parr Tim , Bender David A.
Published: April 2024

This chapter tackles the function of carbohydrate metabolism. Carbohydrates are not essential nutrients since there is no absolute requirement for a dietary intake. However, a very low carbohydrate diet results in chronically increased production and plasma concentrations of the ketone bodies (ketosis) and the absence of glycogen stores since carbohydrate mainly provides metabolic fuel to all tissues. The chapter then explains the main role of dietary carbohydrates as a metabolic fuel, such as affecting satiety, insulin secretion, and glucose homeostasis. It then considers the pathways of carbohydrate metabolism and its regulation before considering the role of glycogen as a carbohydrate reserve.
Fat metabolism
Authors: Calder Philip C. , Yaqoob Parveen
Published: April 2024

This chapter focuses on the notion and main features of fat metabolism. Fat is a major contributor to total energy intakes in most Western diets, and all fat sources contain mixtures of saturated, monounsaturated, and polyunsaturated fatty acids. Fat plays diverse roles in human nutrition, such as a source of energy, both for immediate utilization by the body and in laying down a storage depot. The chapter explains that dietary fat acts as a vehicle for the ingestion and absorption of fat-soluble vitamins. It then considers the relationship between fat, carbohydrate, and protein metabolism and the main regulatory features of fat metabolism.
Protein metabolism and requirements
Authors: Millward Joe D. , Salter Andy
Published: April 2024

This chapter explores protein metabolism and its requirements. Proteins are the most diverse of the large macromolecules which provide structure and enable the function of the organism. The protein quality of human diets is predicted by protein or amino acid digestibility and the amino acid score, which is calculated in comparison with an age-related reference amino acid pattern. Many plant-source proteins have amino acid scores comparable to animal-source proteins, and this is because plant foods are chemically diverse. The chapter then explains that global national protein consumption patterns reflect the intake of animal source foods (ASFs) before mentioning the challenge of meeting protein needs with expanding populations in developing countries.
Water soluble vitamins
Authors: McNulty Helene , Pentieva Kristina
Published: April 2024

This chapter explores compounds classified as water soluble vitamins. Water soluble vitamins act as coenzymes in the process of intermediary metabolism or maintaining antioxidant status. In addition to the normal absorption of water soluble vitamins from foods that occur in the small intestine, intestinal bacteria can synthesize relatively large amounts of some of these vitamins. Thus, the bacterial synthesis of thiamin, riboflavin, nicotinic acid, biotin, and folate can all be increased when the diet contains relatively large amounts of non-starch polysaccharides. The chapter then explains that bacterial synthesis in the colon contributes to vitamin nutrition. It looks into the metabolic interactions between water soluble vitamins and with other nutrients.
Pregnancy and lactation
Authors: Moran Victoria Hall
Published: April 2024

This chapter provides an overview of the process of pregnancy and lactation. Interest in maternal nutrition has increased following the findings of epidemiological studies that connected different patterns of prenatal growth to long-term health. Maternal diet and nutritional status need to be sufficient in pregnancy both to meet the additional nutrient demands that result from the changes. The chapter explains how epigenetic changes modify gene expression without changing the underlying DNA sequence while considering the impact of nutrition in pregnancy on foetal growth and development. It highlights the importance of appropriate nutrition during lactation and its effect on breastmilk composition.