bluuebunny/crossref_metadata_2025 huggingface dataset:
Four enzymes control natural variation in the steroid core ofErysimumcardenolides
Authors: Younkin Gordon C. , Alani Martin L. , Züst Tobias , Jander Georg
Published: April 2024

Plants commonly produce families of structurally related metabolites with similar defensive functions. This apparent redundancy raises the question of underlying molecular mechanisms and adaptive benefits of such chemical variation. Cardenolides, a class defensive compounds found in the wallflower genusErysimum(L., Brassicaceae) and scattered across other plant families, show substantial structural variation, with glycosylation and hydroxylation being common modifications of a steroid core, which itself may vary in terms of stereochemistry and saturation. Through a combination of chemical mutagenesis and analysis of gene coexpression networks, we identified four enzymes involved in cardenolide biosynthesis inErysimumthat work together to determine stereochemistry at carbon 5 of the steroid core: Ec3βHSD, a 3β-hydroxysteroid dehydrogenase, Ec3KSI, a ketosteroid isomerase, EcP5βR2, a progesterone 5β-reductase, and EcDET2, a steroid 5α-reductase. We biochemically characterized the activity of these enzymesin vitroand generated CRISPR/Cas9 knockout lines to confirm activityin vivo. Cardenolide biosynthesis was not eliminated in any of the knockouts. Instead, mutant plants accumulated cardenolides with altered saturation and stereochemistry of the steroid core. Furthermore, we found variation in carbon 5 configuration among the cardenolides of 44 species ofErysimum, where the occurrence of some 5β-cardenolides is associated with the expression and sequence of P5βR2. This may have allowedErysimumspecies to fine-tune their defensive profiles to target specific herbivore populations over the course of evolution.

SIGNIFICANCE STATEMENT

Plants use an array of toxic compounds to defend themselves from attack against insects and other herbivores. One mechanism through which plants may evolve more toxic compounds is through modifications to the structure of compounds they already produce. In this study, we show how plants in the wallflower genusErysimumuse four enzymes to fine-tune the structure of toxic metabolites called cardenolides. Natural variation in the sequence and expression of a single enzyme called progesterone 5β-reductase 2 partly explains the variation in cardenolides observed across theErysimumgenus. These alterations to cardenolide structure over the course of evolution suggests that there may be context-dependent benefits toErysimumto invest in one cardenolide variant over another.
Genome editing in almond: A CRISPR-based approach through hairy root transformation
Authors: Jedličková Veronika , Štefková Marie , Sánchez López Juan Francisco , Grimplet Jérôme , Rubio Cabetas María José , Robert Hélène S.
Published: April 2024

Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) technology has revolutionized genome manipulation for crop enhancement, providing a powerful toolkit. However, the tissue culture and plant regeneration steps that are critical to the CRISPR/Cas editing framework are often challenging, especially in some woody plant species that exhibit substantial resistance to these procedures. To address this, we have developed an injection-based protocol for inducing hairy roots in almond (Prunus dulcis, syn.Prunus amygdalus), a species known for its recalcitrance to conventional transformation methods. Notably, the hairy root induction method also proved effective in almond x peach hybrids. To evaluate its utility for gene functional analysis, we combined the hairy root transformation system with CRISPR/Cas9 gene editing technology, targeting two transcription factor genes (ERF74andGAI). Our efforts resulted in transformants with target knock-out, suggesting the potential of this genetic transformation technology as a valuable tool for future routine gene function studies in almond.
Uptake of small extracellular vesicles by recipient cells is facilitated by paracrine adhesion signaling
Authors: Hirosawa Koichiro M. , Sato Yusuke , Kasai Rinshi S. , Yamaguchi Eriko , Komura Naoko , Ando Hiromune , Hoshino Ayuko , Yokota Yasunari , Suzuki Kenichi G. N.
Published: April 2024

Small extracellular vesicles (sEVs) play crucial roles in intercellular communication. However, the internalization of individual sEVs by recipient cells has not yet been directly observed. Here, we examined these mechanisms using state-of-the-art imaging techniques. Single-molecule imaging showed that tumor-derived sEVs can be classified into several subtypes. Simultaneous single-sEV particle tracking and observation of super-resolution movies of membrane invaginations in living cells revealed that all sEV subtypes were internalized via clathrin-independent endocytosis mediated by galectin-3 and LAMP-2C, while some subtypes that recruited raft markers were internalized through caveolae. Integrin β1 and talin-1 accumulated in recipient cell plasma membranes beneath all sEV subtypes. Paracrine, but not autocrine, sEV binding triggered Ca2+mobilization induced by the activation of Src family kinases and PLCγ. Subsequent Ca2+-induced activation of calcineurin–dynamin promoted sEV internalization, leading to the recycling pathway. Thus, we have clarified the detailed mechanisms of sEV internalization driven by paracrine adhesion signaling.
Adaptive Bayesian quantum algorithm for phase estimation
Authors: Smith Joseph G. , Barnes Crispin H. W. , Arvidsson-Shukur David R. M.
Published: April 2024

Quantum-phase-estimation algorithms are critical subroutines in many applications for quantum computers and in quantum-metrology protocols. These algorithms estimate the unknown strength of a unitary evolution. By using coherence or entanglement to sample the unitary Ntot times, the variance of the estimates can scale as O(1/Ntot2), compared to the best “classical” strategy with O(1/Ntot). The original algorithm for quantum phase estimation cannot be implemented on near-term hardware as it requires large-scale entangled probes and fault-tolerant quantum computing. Therefore, alternative algorithms have been introduced that rely on coherence and statistical inference. These algorithms produce quantum-boosted phase estimates without interprobe entanglement. This family of phase-estimation algorithms have, until now, never exhibited the possibility of achieving optimal scaling O(1/Ntot2). Moreover, previous works have not considered the effect of noise on these algorithms. Here, we present a coherence-based phase-estimation algorithm which can achieve the optimal quadratic scaling in the mean absolute error and the mean squared error. In the presence of noise, our algorithm produces errors that approach the theoretical lower bound. The optimality of our algorithm stems from its adaptive nature: Each step is determined, iteratively, using a Bayesian protocol that analizes the results of previous steps.

Published by the American Physical Society
2024
Strong-field processes induced by an ultrashort linearly polarized pulse with two carrier frequencies
Authors: Habibović D. , Milošević D. B.
Published: April 2024

We perform a detailed semianalytical study of the characteristics of strong-field processes induced by an ultrashort linearly polarized pulse with two carrier frequencies. We show that the photoelectron spectra depend to a great extent on the absolute phases of the field components and on the duration of the pulse. By using the saddle-point method, we show that this dependence can be exploited to control the electron dynamics in the laser field. Besides the photoelectron spectra, we also investigate the spectra of high-order harmonics. Again, we find a strong dependence on the absolute phases and the duration of the pulse. We present the spectra using a false color scale in the absolute phase-harmonic energy plane, and show that particular regions in this plane can be assessed using the simple man's model founded on the classical solution of the Newton equation of motion. Finally, we investigate the symmetry properties of the photoelectron and high-order harmonic spectra with respect to the transformation which includes the change of the absolute phase, and compare them with those valid for a long driving pulse with a flat envelope.

Published by the American Physical Society
2024
Terahertz-driven acceleration of subrelativistic electron beams using tapered rectangular dielectric-lined waveguides
Authors: Nix Laurence J. R. , Bradbury Joseph T. , Shaw Christopher T. , Hibberd Morgan T. , Graham Darren M. , Appleby Robert B. , Burt Graeme , Letizia Rosa , Jamison Steven P.
Published: April 2024

We investigate the use of tapered rectangular dielectric-lined waveguides (DLWs) for the acceleration of low-energy, subrelativistic, electron bunches by the interaction with multicycle narrowband terahertz (THz) pulses. A key challenge exists in this subrelativistic regime; the electron velocity changes significantly as energy is gained. To keep electrons in the accelerating phase, the phase velocity must also be increased to match. We present simulations which demonstrate that the dielectric thickness can be kept constant and the width of the dielectric lining can be tapered along the direction of travel to vary the phase velocity, an approach only possible by the use of a rectangular waveguide geometry. The properties of tapered DLWs are discussed and following this, a design process is presented to demonstrate that the way this tapering can be optimized for different pulse and beam parameters. The minimum accelerating gradient for electron bunch capture is derived and compared to simulations. As examples of this design process, designs are considered based on considerations of the THz source, incoming electron beam, and manufacturing tolerances. A maximum THz pulse energy of 22.5  μJ in the DLW was considered, which represents what is readily achievable using mJ-level regenerative amplifier laser systems together with optical-to-terahertz conversion in lithium niobate crystals. This will be more than double the energy of a 100 keV electron beam, increasing it to 205 keV. We describe the optimization process and present a detailed exploration of the beam dynamics, discussing how the performance will further improve with compressed bunches.

Published by the American Physical Society
2024
Unidirectional multipulse helicity-independent all-optical switching in [Ni/Pt] based synthetic ferrimagnets
Authors: Sait Connor R. J. , Dąbrowski Maciej , Scott Jade N. , Hendren William R. , Newman David G. , N'Diaye Alpha T. , Klewe Christoph , Shafer Padraic , van der Laan Gerrit , Keatley Paul S. , Bowman Robert M. , Hicken Robert J.
Published: April 2024

Nickel-platinum-based synthetic ferrimagnets (SFi's) are highly tunable and rare-earth-free materials that allow ultrafast all optical control of magnetism to be explored. This study considers a SFi composed of a ferromagnetic [Ni/Pt] multilayer and a ferromagnetic Co layer, separated by an Ir layer that mediates an antiferromagnetic coupling. Helicity-independent all optical switching (HI-AOS) between two antiparallel magnetization states is observed. AOS may be realized at increased temperature through reduction of the thickness of the Pt layers. Switching is unidirectional and has a strong dependence on the applied magnetic field history, which suggests the possible presence of a nanoscale magnetic texture that may be important in controlling AOS in SFi systems.

Published by the American Physical Society
2024
Role of Coulomb interaction in elastic pion-proton scattering from holography
Authors: Zhang Yu-Peng , Chen Xun , Li Xiao-Hua , Watanabe Akira
Published: April 2024

Differential cross sections of the elastic pion-proton scattering are investigated at very small momentum transfer in a holographic QCD model, considering both the strong and Coulomb interaction in the Regge regime. The strong interaction is described by the Pomeron and Reggeon exchange, and the Coulomb interaction is characterized by the one photon exchange. The two interactions are linked through an interference term and we only need to determine a single adjustable parameter involved in this term. As to the parameters for the strong interaction, we can utilize the values determined in the previous studies. The differential cross sections can be predicted without any additional parameters, and it is shown that our predictions are consistent with the experimental data. We explicitly show the momentum transfer dependence for the interference effect. The energy dependence of the contribution ratios for each component is also discussed.

Published by the American Physical Society
2024
Long-lived particle decays at the proposed MATHUSLA experiment
Authors: Curtin David , Grewal Jaipratap Singh
Published: April 2024

We carefully study the decay and reconstruction of long-lived particle (LLP) decays in the proposed MATHUSLA LLP detector for the HL-LHC. Our investigations are focused on three LLP benchmark models. MATHUSLA’s primary physics target is represented by hadronically decaying LLPs with mass above ∼10  GeV, produced in exotic Higgs decays. We also investigate GeV-scale scalar and right-handed neutrino LLPs, which are the target of many other proposed experiments. We first introduce a public astim code to allow for efficient signal-only studies of LLP decays in MATHUSLA and general external LLP detectors. For each of our benchmark scenarios, we carefully simulate LLP production and decay, and make our simulation library publicly accessible for future investigations and comparisons with other experiments. We then systematically study the geometric acceptance of MATHUSLA for LLP decays in these scenarios, and present updated sensitivity projections that include these acceptances. Our results show that the idealized reach of MATHUSLA computed in earlier studies is mostly realized. We also investigate possible ways of increasing the signal acceptance using the inherent geometric flexibility of the FastSim, which will provide useful inputs for realistic experimental and engineering optimization of the detector in the future.

Published by the American Physical Society
2024
Top Yukawa coupling measurement at the muon collider
Authors: Chen Miranda , Liu Da
Published: April 2024

We have presented a detailed study about the prospects for the measurement of the top Yukawa coupling in the vector boson fusion production of a top quark pair at high energy muon colliders. By employing the effective W approximation and the high energy limit for the helicity amplitudes of the subprocess W+W−→tt¯, we have derived the energy scaling of the statistical signal significance in the presence of the anomalous couplings by focusing on the interference term only. The sensitivity on the top Yukawa coupling decreases as the bin energy increases. For the anomalous triple gauge boson couplings and the gauge-boson-fermion couplings with E2 energy growing behavior, the signal significance has mild increase at the beginning and starts to decrease for s^tt¯∼0.2sμ+μ−. The 95% CL on the anomalous top Yukawa coupling is projected to be 5.6% (1.7%) at a 10 (30) TeV muon collider, which is comparable to the sensitivity of 2% at the 100 TeV collider.

Published by the American Physical Society
2024
Analytic approximations for the primordial power spectrum with Israel junction conditions
Authors: Dineen D. D. , Handley W. J.
Published: April 2024

This work compares cosmological matching conditions used in approximating generic pre-inflationary phases of the Universe. We show that the joining conditions for primordial scalar perturbations assumed by Contaldi [] are inconsistent with the physically motivated Israel junction conditions; however, performing general relativistic matching with the aforementioned constraints results in unrealistic primordial power spectra. Eliminating the need for ambiguous matching, we look at an alternative semianalytic model for producing the primordial power spectrum allowing for finite duration cosmological phase transitions.

Published by the American Physical Society
2024
Quantum phase transition and absence of quadratic divergence in generalized quantum field theories
Authors: Kawai Hikaru , Kawana Kiyoharu , Oda Kin-ya , Yagyu Kei
Published: April 2024

In ordinary thermodynamics, around first-order phase transitions, the intensive parameters such as temperature and pressure are automatically fixed to the phase transition point when one controls the extensive parameters such as total volume and total energy. From the microscopic point of view, the extensive parameters are more fundamental than the intensive parameters. Analogously, in conventional quantum field theory (QFT), coupling constants (including masses) in the path integral correspond to intensive parameters in the partition function of the canonical formulation. Therefore, it is natural to expect that, in a more fundamental formulation of QFT, coupling constants are dynamically fixed , just as the intensive parameter in the microcanonical formulation. Here, we demonstrate that the automatic tuning of the coupling constants is realized at a quantum phase transition point at zero temperature, even when the transition is of higher order, due to the Lorentzian nature of the path integral. This naturally provides a basic foundation for the multicritical point principle. As a concrete toy model for solving the Higgs hierarchy problem, we study how the mass parameter is fixed in the ϕ4 theory at the one-loop level in the microcanonical or further generalized formulation of QFT. We find that there are two critical points for the renormalized mass: zero and of the order of ultraviolet cutoff. In the former, the Higgs mass is automatically tuned to be zero and thus its fine-tuning problem is solved. We also show that the quadratic divergence is absent in a more realistic two-scalar model that realizes the dimensional transmutation. Additionally, we explore the possibility of fixing quartic coupling in ϕ4 theory and find that it can be fixed to a finite value.

Published by the American Physical Society
2024
Page-curve-like entanglement dynamics in open quantum systems
Authors: Glatthard Jonas
Published: April 2024

The entanglement entropy of a black hole and that of its Hawking radiation are expected to follow the so-called Page curve: After an increase in line with Hawking’s calculation, it is expected to decrease back to zero once the black hole has fully evaporated, as demanded by unitarity. Recently, a simple system-plus-bath model has been proposed which shows a similar behavior. Here, we make a general argument as to why such a Page-curve-like entanglement dynamics should be expected to hold generally for system-plus-bath models at small coupling and low temperatures, when the system is initialized in a pure state far from equilibrium. The interaction with the bath will then generate entanglement entropy, but it eventually has to decrease to the value prescribed by the corresponding mean-force Gibbs state. Under those conditions, it is close to the system ground state. We illustrate this on two paradigmatic open-quantum-system models, the exactly solvable harmonic quantum Brownian motion and the spin-boson model, which we study numerically. In the first example we find that the intermediate entropy of an initially localized impurity is higher for more localized initial states. In the second example, for an impurity initialized in the excited state, the Page time—when the entropy reaches its maximum—occurs when the excitation has half decayed.

Published by the American Physical Society
2024
Vortex Effects in Merging Black Holes and Saturons
Authors: Dvali Gia , Kaikov Oleg , Kühnel Florian , Valbuena-Bermúdez Juan Sebastián , Zantedeschi Michael
Published: April 2024

Vorticity has recently been suggested to be a property of highly spinning black holes. The connection between vorticity and limiting spin represents a universal feature shared by objects of maximal microstate entropy, so-called saturons. Using Q-ball-like saturons as a laboratory for black holes, we study the collision of two such objects and find that vorticity can have a large impact on the emitted radiation as well as on the charge and angular momentum of the final configuration. As black holes belong to the class of saturons, we expect that the formation of vortices can cause similar effects in black hole mergers, leading to macroscopic deviations in gravitational radiation. This could leave unique signatures detectable with upcoming gravitational-wave searches, which can thereby serve as a portal to macroscopic quantum effects in black holes.

Published by the American Physical Society
2024
Stable and unstable tiling patterns formed by ABC miktoarm star triblock terpolymers of symmetric interactions
Authors: Hawthorne Cody , He Juntong , Wang Qiang
Published: April 2024

Several discrepancies exist among previous self-consistent field calculations of symmetrically interacting ABC miktoarm star triblock terpolymer melts. Here we address this issue by including all known tiling patterns, as well as several lamellar-type phases known to bound the regions in the parameter space occupied by these patterns. After carefully studying the effect of numerical parameters on the free-energy accuracy, the central region of the phase diagram is constructed in detail; both the (3.4.6.4) pattern and the three-dimensional phase of hierarchical-hexagonal lamellae are found to be stable for the first time. The energetic and entropic contributions to the free-energy density of several phases are analyzed and compared in detail to reveal their stability mechanisms, including the important (32.4.3.4) pattern. Comparisons to previous studies of the same model system are present throughout, with our results resolving the aforementioned discrepancies and providing a sound basis for future work to build upon.

Published by the American Physical Society
2024
Validation of two test anxiety scales for physics undergraduate courses through confirmatory factor analysis and Rasch analysis
Authors: Cioffi Agostino , Galano Silvia , Passeggia Raffaella , Testa Italo
Published: April 2024

The assessment of test anxiety has received increasing attention in educational research due to the potential negative effects of anxiety on student performance. Traditionally, test anxiety scales have been developed for mathematics, but few studies have focused on physics. In this study, we validated two test anxiety scales for undergraduate physics courses: the Test Anxiety Inventory for Physics (TAIP) and the Abbreviated Test Anxiety Inventory for Physics scale (ATAIP), which were adapted from existing instruments. A convenience sample of 361 engineering students enrolled in a first-semester introductory physics course participated in the study. Confirmatory factor analysis and Rasch analysis were used to establish the construct validity of both scales. Convergent validity for the TAIP scale was established by examining its correlation with a scale adapted from the math anxiety scale. Criterion-related validity for both TAIP and ATAIP was established by analyzing the relationship between students’ Rasch scores on the two scales and their performance on two conceptual tests. Finally, measurement invariance of TAIP and ATAIP scales was established using both multigroup and differential item functioning analyses to reliably investigate gender differences in the corresponding Rasch measures. The study confirms a robust four-factor structure of the TAIP. The four subscales, Worry, Emotionality, Interference, and Lack of Confidence, demonstrate good reliability (McDonald’s ω=0.78,0.86,0.87,87, respectively). Rash analysis also confirms that, for each subscale, the rating scale functioning was consistent with the item difficulty and person measures. The TAIP also demonstrates adequate convergent and criterion-related validity, as well as measurement invariance with respect to gender. The ATAIP also demonstrates good reliability (McDonald’s ω=0.84), a well-functioning rating scale, and sufficient criterion-related validity. Additionally, it exhibits measurement invariance with respect to gender. Overall, the study supports that both the TAIP and ATAIP scales are reliable instruments for measuring students’ test anxiety in an undergraduate physics course. Implications for physics instruction at the university introductory level are briefly discussed.

Published by the American Physical Society
2024
Narrowly avoided spin-nematic phase in
BaCdVO(PO4)2: NMR
evidence
Authors: Ranjith K. M. , Povarov K. Yu. , Yan Z. , Zheludev A. , Horvatić M.
Published: April 2024

We present a P31 NMR investigation of BaCdVO(PO4)2 focusing on the nearly saturated regime between μ0Hc1=4.05T and μ0Hc2=6.5T, which used to be considered a promising candidate for a spin-nematic phase. NMR spectra establish the absence of any dipolar order there, whereas the weak field dependence of the magnetization above Hc1 is accounted for by Dzyaloshinskii-Moriya interaction terms. The low-energy spin dynamics (fluctuations), measured by the nuclear spin-lattice relaxation rate T1−1, confirms the continuity of this phase and the absence of any low-temperature phase transition. Unexpectedly, the spin dynamics above Hc1 is largely dominated by two-magnon processes, which is expected the saturation field of a spin-nematic phase, but not inside. This shows that BaCdVO(PO4)2 is indeed close to a spin-nematic instability; however, this phase is stabilized. We thus confirm recent theoretical predictions that the spin-nematic phase can be stabilized, at most, in an extremely narrow field range close to saturation or is rather narrowly avoided [Jiang , ].

Published by the American Physical Society
2024
Modulation instability and wavenumber bandgap breathers in a time layered phononic lattice
Authors: Chong Christopher , Kim Brian , Wallace Evelyn , Daraio Chiara
Published: April 2024

We provide the first experimental realization of wavenumber bandgap (q−gap) breathers. Experiments are obtained in the setting of a time-periodic phononic lattice where the model and experiment exhibit good qualitative agreement. q−gap breathers are localized in time and periodic in space, and are the counterparts to the classical breathers found in space-periodic systems. We derive an exact condition for modulation instability that leads to the opening of wavenumber bandgaps in which the q−gap breathers can arise. The q−gap breathers become more narrow and larger in amplitude as the wavenumber goes further into the bandgap. In the presence of damping, these structures acquire a nonzero, oscillating tail. The controllable temporal localization that q−gap breathers make possible has potential applications in the creation of phononic frequency combs, energy harvesting or acoustic signal processing.

Published by the American Physical Society
2024
Optimally localized single-band Wannier functions for two-dimensional Chern insulators
Authors: Gunawardana Thivan M. , Turner Ari M. , Barnett Ryan
Published: April 2024

The construction of optimally localized Wannier functions (and Wannier functions in general) for a Chern insulator has been considered to be impossible owing to the fact that the second moment of such functions is generally infinite. In this article, we propose a solution to this problem in the case of a single band isolated from the rest of the band structure. We accomplish this by drawing an analogy between the minimization of the variance and the minimization of the electrostatic energy of a periodic array of point charges in a smooth neutralizing background. In doing so, we obtain a natural regularization of the diverging variance and this leads to an analytical solution to the minimization problem. We demonstrate our results numerically for a particular model system. Furthermore, we show how the optimally localized Wannier functions provide a natural way of evaluating the electric polarization for a Chern insulator.

Published by the American Physical Society
2024
Symplectic Geometry and Circuit Quantization
Authors: Osborne Andrew , Larson Trevyn , Jones Sarah Garcia , Simmonds Ray W. , Gyenis András , Lucas Andrew
Published: April 2024

Circuit quantization is an extraordinarily successful theory that describes the behavior of quantum circuits with high precision. The most widely used approach of circuit quantization relies on introducing a classical Lagrangian whose degrees of freedom are either magnetic fluxes or electric charges in the circuit. By combining nonlinear circuit elements (such as Josephson junctions or quantum phase slips), it is possible to build circuits where a standard Lagrangian description (and thus the standard quantization method) does not exist. Inspired by the mathematics of symplectic geometry and graph theory, we address this challenge, and present a Hamiltonian formulation of nondissipative electrodynamic circuits. The resulting procedure for circuit quantization is independent of whether circuit elements are linear or nonlinear, or if the circuit is driven by external biases. We explain how to rederive known results from our formalism, and provide an efficient algorithm for quantizing circuits, including those that cannot be quantized using existing methods.

Published by the American Physical Society
2024
Synthesis, crystal structure and properties of the trigonal–bipyramidal complex tris(2-methylpyridine N-oxide-κO)bis(thiocyanato-κN)cobalt(II)
Authors: Näther Christian , Jess Inke
Published: April 2024

Reaction of Co(NCS)2 with 2-methylpyridine N-oxide in a 1:3 ratio in n-butanol leads to the formation of crystals of tris(2-methylpyridine N-oxide-κO)bis(thiocyanato-κN)cobalt(II), [Co(NCS)2(C6H7NO)3]. The asymmetric unit of the title compound consists of one CoII cation two thiocyanate anions and three crystallographically independent 2-methylpyridine N-oxide coligands in general positions. The CoII cations are trigonal–bipyramidally coordinated by two terminal N-bonding thiocyanate anions in the trans-positions and three 2-methylpyridine N-oxide coligands into discrete complexes. These complexes are linked by intermolecular C–H...S interactions into double chains that elongate in the c-axis direction. Powder X-ray diffraction (PXRD) measurements prove that all batches are always contaminated with an additional and unknown crystalline phase. Thermogravimetry and differential analysis of crystals selected by hand reveal that the title compound decomposes at about 229°C in an exothermic reaction. At about 113°C a small endothermic signal is observed that, according to differential scanning calorimetry (DSC) measurements, is irreversible. PXRD measurements of the residue prove that a poorly crystalline and unknown phase has formed and thermomicroscopy indicates that some phase transition occurs that is accompanied with a color change of the title compound.
Dependence and sustainability: a disaggregated analysis of electricity generation in ASEAN countries
Authors: Hartarto Romi Bhakti , Shameem P. Mohammed , Wardani Dyah Titis Kusuma , Iskandar Muhammad Luqman
Published: April 2024

Purpose

This study aims to explore the diverse sources of electricity generation (coal, natural gas, oil and hydroelectricity) and their respective associations with economic growth and environmental quality.

Design/methodology/approach

This study uses static panel data analysis with a random effects model for six selected ASEAN countries (Indonesia, Malaysia, Filipina, Thailand, Vietnam and Myanmar) from 1994 to 2014.

Findings

This study reveals that economic growth in six selected ASEAN countries is enhanced by electricity generation from all sources, while the contribution of electricity production from hydroelectricity remains the largest and strongest. There is no environmental impact of electricity production from hydroelectric, whereas fossil fuel-based electricity production emits carbon dioxide, with coal sources being the largest contributor, followed by natural gas and oil.

Practical implications

Based on the results, these six ASEAN countries should invest more in hydropower projects, reduce the coal mix in power generation and promote clean coal technology to improve economic efficiency and environmental sustainability.

Originality/value

To the best of the authors’ knowledge, no research has examined the relationship between electricity production, environmental quality and economic growth in Southeast Asian nations. Therefore, the outcome of this study is expected to provide insightful results to supplement the framing and implementation of national and collective regional strategies for sustainable electricity generation in ASEAN countries.
Lean transportation tools towards waste reduction and digital transformation in the offshore industry: an action-research
Authors: Gomes Joici Mendonça Muniz , Caiado Rodrigo Goyannes Gusmão , Mareth Taciana , Santos Renan Silva , Scavarda Luiz Felipe
Published: April 2024

Purpose

To address the absence of Lean in transportation logistics in the digital era, this study aims to investigate the application of Lean transportation (LT) tools to reduce waste and facilitate the digital transformation of dedicated road transportation in the offshore industry.

Design/methodology/approach

The study adopts action research with a multimethod approach, including a scoping review, focus groups (FG) and participant observation. The research is conducted within the offshore supply chain of a major oil and gas company.

Findings

Implementing LT’s continuous improvement tools, particularly value stream mapping (VSM), reduces offshore transportation waste and provides empirical evidence about the intersection of Lean and digital technologies. Applying techniques drawn from organisational learning theory (OLT), stakeholders involved in VSM mapping and FGs engage in problem-solving and develop action plans, driving digital transformation. Waste reduction in loading and unloading stages leads to control actions, automation and process improvements, significantly reducing downtime. This results in an annual monetary gain of US$1.3m. The study also identifies waste related to human effort and underutilised digital resources.

Originality/value

This study contributes to theory and practice by using action research and LT techniques in a real intervention case. From the lens of OLT, it highlights the potential of LT tools for digital transformation and demonstrates the convergence of waste reduction through Lean and Industry 4.0 technologies in the offshore supply chain. Practical outputs, including a benchmarking questionnaire and a plan-do-check-act cycle, are provided for other companies in the same industry segment.
The degree of Asian-European markets connectedness: examining the impact of global disorders using a spectral analysis
Authors: Dimitriou Dimitrios , Goulas Eleftherios , Kallandranis Christos , Tsioutsios Alexandros , Ta Thi Ngoc Bich Thi Ngoc
Published: April 2024

Purpose

This paper aims to examine potential diversification benefits between Eurozone (i.e. EURO STOXX 50) and key Asia markets: HSI (Hong Kong), KOSPI (South Korea), NIKKEI 225 (Japan) and TSEC (Taiwan). The sample covers the period from 04-01-2008 to 19-10-2023 in daily frequency.

Design/methodology/approach

The empirical investigation is based on the wavelet coherence analysis, which is a localized correlation coefficient in the time and frequency domain.

Findings

The results provide evidence that long-term diversification benefits exist between EURO STOXX and NIKKEI, EURO STOXX and KOSPI (after 2015) and there are signs for the pair and EURO STOXX-TSEC (after 2014). During the short term, there are signs of diversification benefits during the sample period. However, during the medium term, the diversification benefits seem to diminish.

Originality/value

These results have crucial implications for investors regarding the benefits of international portfolio diversification.
Turning digital technology to immersive marketing strategy: a strategic perspective on flexibility, agility and adaptability for businesses
Authors: Yawised Kritcha , Apasrawirote Darlin , Chatrangsan Maneerut , Muneesawang Paisarn
Published: April 2024

Purpose

The purpose of this study is to conduct a systematic literature review of the adoption of immersive marketing technology (IMT) in terms of strategic planning of its adoption, resource requirements and its implications and challenges.

Design/methodology/approach

This study categorizes and contextualizes qualitative approaches to evaluate the literature, with Scopus databases serving as the primary source of 90 selected articles in the areas of information technology, business and marketing strands. Theme analysis was carried out using thematic techniques and grounded approach principles to facilitate thematic coding and generate theme analysis.

Findings

The analysis was supported by the three concepts of business flexibility, agility and adaptability, which were drawn as a strategy for IMT adoption. The findings presented three main themes: proactive flexibility, responsive agility and reactive adaptability that enable business owner–managers to craft a strategy for IMT adoption.

Originality/value

The novel contribution of this study is the inclusion of key implications related to IMT as a starting point of the next level of innovative marketing for all academics, practitioners and business owner–managers.
The paradox of Islamic perception on the entrepreneurial intentions of female Muslims in Pakistan
Authors: Khan Mohammad Saud , Wood Bronwyn Pamela , Dakhan Sarfraz , Nawaz Asif
Published: April 2024

Purpose

This paper aims to examine female entrepreneurship perceptions at the nexus of understandings of Muslim behaviour in Pakistan, the “formula” of Shapero for considering entrepreneurial intentions and the viewpoints of young Pakistani women.

Design/methodology/approach

Data collected from 555 women between 18 and 30 years of age, undertaking tertiary-level business studies in Pakistan constitute the sample of the study, and structural equation modelling was used to test the hypotheses.

Findings

This study finds that the respondents’ perceptions of Islam positively impact the formula at the feasibility component, whilst also inverting the desirability component, therefore, resulting in a “does not equal” outcome for intentions.

Originality/value

To the best of the authors’ knowledge, this work is one of the first to empirically examine the role of Islamic perception in shaping entrepreneurial intentions through the individual components of desirability, feasibility and propensity to act. It puts forth contextual deliberations for a meaningful heterodoxy in light of female entrepreneurship in an Islamic country.
Presence: consumers’ different reactions to service and manufacturing firms with low CSR in social conduct
Authors: Meng Hua , Sadjady Naeeni Hannan
Published: April 2024

Purpose

This study aims to explain why low social conduct in corporate social responsibility (SC-CSR), especially employee exploitation, has a stronger negative impact on consumer reactions for service firms than for manufacturing firms.

Design/methodology/approach

Five experiments compared consumer reactions to service and manufacturing firms with low SC-CSR. Study 1 used a choice-based conjoint design to examine the relative importance of various shared attributes when consumers chose services versus goods. Study 2 revealed that low SC-CSR led to more pronounced negative consumers reactions toward service firms. Studies 3A and 3B explained this difference through a serial mediation analysis. Study 4 ruled out an alternative explanation regarding the differentiated effects.

Findings

The results reveal that consumer reactions to employee exploitation in service firms are more negative compared to manufacturing firms. This is because consumers’ sense of presence (i.e. feeling of being there) is stronger in a service setting, leading to more intense empathetic emotions toward service employees.

Originality/value

This research contributes to the CSR literature by challenging the conventional notion that sweatshops are more problematic for manufacturing firms. By contrast, the results indicate a stronger negative effect on service firms. It contributes to the services marketing literature by conceptualizing a novel cognitive mechanism. Traditionally, consumers’ negative reactions are driven by anger. However, the authors show that empathetic feelings toward mistreated employees play a predominant role. While it is imperative for all firms to ensure fair treatment of their employees, the findings underscore the heightened significance of this aspect for service firms, given their susceptibility to more pronounced negative effects.
The use of implicit measures in service research: Why, how, when and what is the way forward?
Authors: Verhulst Nanouk , Slabbinck Hendrik , Willems Kim , Brengman Malaika
Published: April 2024

Purpose

To date, to the best of the authors’ knowledge, the use of implicit measures in the service research domain is limited. This paper aims to introduce implicit measures and explain why, or for what purpose, they are worthwhile to consider; how these measures can be used; and when and where implicit measures merit the service researcher’s consideration.

Design/methodology/approach

To gain an understanding of how implicit measures could benefit service research, three promising implicit measures are discussed, namely, the implicit association test, the affect misattribution procedure and the propositional evaluation paradigm. More specifically, this paper delves into how implicit measures can support service research, focusing on three focal service topics, namely, technology, affective processes including customer experience and service employees.

Findings

This paper demonstrates how implicit measures can investigate paramount service-related subjects. Additionally, it provides essential methodological “need-to-knows” for assessing others’ work with implicit measures and/or for starting your own use of them.

Originality/value

This paper introduces when and why to consider integrating implicit measures in service research, along with a roadmap on how to get started.
Innovations in prosthetic foot design enhancing durability, functionality and comfort through PLA composite filament 3D printing
Authors: Yousif Lara E. , Abed Mayyadah S. , Al-Zubidi Aseel B. , Resan Kadhim K.
Published: April 2024

Purpose

The number of people with special needs, including citizens and military personnel, has increased as a result of terrorist attacks and challenging conditions in Iraq and other countries. With almost 80% of the world’s amputees having below-the-knee amputations, Iraq has become a global leader in the population of amputees. Important components found in lower limb prostheses include the socket, pylon (shank), prosthetic foot and connections.

Design/methodology/approach

There are two types of prosthetic feet: articulated and nonarticulated. The solid ankle cushion heel foot is the nonarticulated foot that is most frequently used. The goal of this study is to use a composite filament to create a revolutionary prosthetic foot that will last longer, have better dorsiflexion and be more stable and comfortable for the user. The current study, in addition to pure polylactic acid (PLA) filament, 3D prints test items using a variety of composite filaments, such as PLA/wood, PLA/carbon fiber and PLA/marble, to accomplish this goal. The experimental step entails mechanical testing of the samples, which includes tensile testing and hardness evaluation, and material characterization by scanning electron microscopy-energy dispersive spectrometer analysis. The study also presents a novel design for the nonarticulated foot that was produced with SOLIDWORKS and put through ANSYS analysis. Three types of feet are produced using PLA, PLA/marble and carbon-covered PLA/marble materials. Furthermore, the manufactured prosthetic foot undergoes testing for dorsiflexion and fatigue.

Findings

The findings reveal that the newly designed prosthetic foot using carbon fiber-covered PLA/marble material surpasses the PLA and PLA/marble foot in terms of performance, cost-effectiveness and weight.

Originality/value

To the best of the author’s knowledge, this is the first study to use composite filaments not previously used, such as PLA/wood, PLA/carbon fiber and PLA/marble, to design and produce a new prosthetic foot with a longer lifespan, improved dorsiflexion, greater stability and enhanced comfort for the patient. Beside the experimental work, a numerical technique specifically the finite element method, is used to assess the mechanical behavior of the newly designed foot structure.
A memory and attention-based reinforcement learning for musculoskeletal robots with prior knowledge of muscle synergies
Authors: Wang Xiaona , Chen Jiahao , Qiao Hong
Published: April 2024

Purpose

Limited by the types of sensors, the state information available for musculoskeletal robots with highly redundant, nonlinear muscles is often incomplete, which makes the control face a bottleneck problem. The aim of this paper is to design a method to improve the motion performance of musculoskeletal robots in partially observable scenarios, and to leverage the ontology knowledge to enhance the algorithm’s adaptability to musculoskeletal robots that have undergone changes.

Design/methodology/approach

A memory and attention-based reinforcement learning method is proposed for musculoskeletal robots with prior knowledge of muscle synergies. First, to deal with partially observed states available to musculoskeletal robots, a memory and attention-based network architecture is proposed for inferring more sufficient and intrinsic states. Second, inspired by muscle synergy hypothesis in neuroscience, prior knowledge of a musculoskeletal robot’s muscle synergies is embedded in network structure and reward shaping.

Findings

Based on systematic validation, it is found that the proposed method demonstrates superiority over the traditional twin delayed deep deterministic policy gradients (TD3) algorithm. A musculoskeletal robot with highly redundant, nonlinear muscles is adopted to implement goal-directed tasks. In the case of 21-dimensional states, the learning efficiency and accuracy are significantly improved compared with the traditional TD3 algorithm; in the case of 13-dimensional states without velocities and information from the end effector, the traditional TD3 is unable to complete the reaching tasks, while the proposed method breaks through this bottleneck problem.

Originality/value

In this paper, a novel memory and attention-based reinforcement learning method with prior knowledge of muscle synergies is proposed for musculoskeletal robots to deal with partially observable scenarios. Compared with the existing methods, the proposed method effectively improves the performance. Furthermore, this paper promotes the fusion of neuroscience and robotics.