bluuebunny/crossref_metadata_2025 huggingface dataset:
Unscrambling traffic congestion and increasing sustainability in special urban intersection
Authors: R Radhakrishnan , Ajimon M. Anjana , Bose Shalu , S Surya , Pillai Vishnu G. , Sandeep U.P.
Published: May 2024

Traffic congestion in India's densely populated urban centres is a major challenge exacerbated by rapid urbanization and a surge in vehicles surpassing infrastructure growth. Gridlocks and slow-moving vehicles are common due to inadequate road networks and poorly planned intersections, leading to longer commutes, productivity loss, and heightened pollution and safety concerns. Mitigation efforts include infrastructure upgrades and sustainable transportation promotion, implementing Indian Road Congress (IRC) signal design guidelines for intersection optimization and traffic flow management. Pedestrian safety remains critical, requiring comprehensive strategies integrating public transportation enhancement, road infrastructure optimization, and alternative travel modes promotion. Utilizing advanced technology for traffic monitoring, alongside urban planning initiatives prioritizing efficient land use and mixed-use developments, is crucial. Furthermore, policies promoting telecommuting and flexible work schedules can help alleviate the burden of peak-hour traffic. Flyovers offer relief by allowing vehicles to bypass congested areas, improving traffic flow. Congestion indirectly contributes to pollution, emphasizing the importance of catalytic converters in reducing harmful emissions from vehicle exhaust. This comprehensive approach aims to create smoother and more sustainable transportation systems while addressing congestion and pollution issues effectively.
Analysis on Automatic International Classification of Disease Coding with Medical Records
Authors: Joseph Neena , P Vijayan Vinodh
Published: May 2024

The clinical concepts in the information gathered from the healthcare services are categorized and standardized using medical coding. The International Classification of Diseases (ICD) includes codes for various diseases that have an impact on financing, reporting, and research. In order to provide patient care and billing, medical coding allocates a subset of ICD codes to each patient visit. Medical personnel must spend a lot of time and effort on manual medical coding, which can lead to missed revenue and claim denials. Different studies on machine learning achieved promising performance for automated medical coding. Many researchers carried out their research on ICD. But, heterogeneous mode of operations by doctors and diagnosis methods makes the medical coding as more complex one. Furthermore, the current ICD approaches did not reduce computational complexity or increase accuracy. To address these problems, a range of deep learning and machine learning approaches are tested for ICD.
Exploring PFOA adsorption isotherm in the presence of NOM using DBD plasma-modified GAC
Authors: Sahara Thera , Wongsawaeng Doonyapong , Ngaosuwan Kanokwan , Kiatkittipong Worapon , Hosemann Peter , Assabumrungrat Suttichai
Published: May 2024

Perfluorooctanoic acid (PFOA), a widely used perfluorinated alkyl substance (PFAS), poses significant environmental and health risks. This study investigates PFOA adsorption in the existence of natural organic matter (NOM) using granular activated carbon (GAC) modified with dielectric barrier discharge (DBD) plasma. PFOA’s amphiphilic structure, characterized by a hydrophilic carboxyl group head and a hydrophobic perfluorinated tail, contributes to its versatility and persistence. The selection of the Chao Phraya River (CPR) water as the NOM source, captures the complexity of a major water body subjected to diverse pollution sources. The results were analyzed through the Toth and Temkin isotherm models. Application of the Toth isotherm model reveals enhanced PFOA adsorption capacity in CPR water compared to DI water, emphasizing the influence of NOM. The Temkin isotherm analysis further characterizes the strength and efficiency of the adsorption process, highlighting a stronger interaction between PFOA and plasma-modified GAC in CPR water. The study indicates that the adsorption process in CPR water may be more influenced by PFOA surface coverage on the GAC surface in the presence of NOM. Overall, this research contributes valuable insights into pollutant removal strategies, highlighting the potential of DBD plasma-modified GAC in addressing PFOA contamination challenges in water systems.
Parallel illumination for depletion microscopy through acousto-optic spatial light modulation
Authors: Klingmann Fabian , Toledo-García Nick , Martín-Badosa Estela , Montes-Usategui Mario , Tiana-Alsina Jordi
Published: May 2024

State-of-the-art super-resolution microscopy techniques, including Stimulated Emission Depletion (STED), Reversible Saturable Optical Fluorescence Transitions (RESOLFT), and Switching Laser Mode (SLAM) microscopies, implement Laguerre-Gaussian beams, also known as vortex or doughnut beams to capture fluorescence information within a sub-wavelength area of the observed sample, effectively surpassing the diffraction limit and significantly improving the quality of the image. However, these techniques typically operate at point by point basis, involving time-consuming scanning of the sample to construct a complete, meaningful image. Therefore, for real-time live cell imaging purposes, the parallelization of illumination is crucial. In this study, we demonstrate the parallel generation of arbitrary arrays of Gaussian and Laguerre-Gaussian laser foci suitable for super-resolution microscopy. We achieve rapid scanning through the sample using acousto-optic spatial light modulation, a technique we have previously pioneered across various fields. By employing parallelized illumination with both Gaussian and doughnut beams, we aim to capture super-resolution images.
Touching Surfaces: einfache Anwendung, große Auswirkung
Authors: Krämer Carolin L. , Siems Katharina , Müller Daniel W. , Leuko Stefan , Mücklich Frank , Maurer Matthias , Moeller Ralf
Published: May 2024

Mikroorganismen begleiten uns in unserem Alltag als essenzieller Teil des menschlichen Körpers und der von uns bewohnten Lebensräume. Während viele der Mikroorganismen für uns Menschen nützlich sind, können einige von ihnen Infektionen verursachen. Die einzigartigen Bedingungen, die während Raumfahrtmissionen vorliegen, wirken sich auch auf das Immunsystem aus, wodurch opportunistische Pathogene eine Gefahr darstellen können. Viele Mikroorganismen können lange auf Oberflächen überleben, die dadurch zu einer Quelle der Verbreitung von opportunistisch pathogenen Mikroorganismen werden. Um diese Verbreitung zu verhindern, können antimikrobielle Oberflächen eingesetzt werden. Touching Surfaces ist ein interdisziplinäres Projekt, das antibakterielle Oberflächen für die Anwendung in Raumfahrt und auf der Erde testet. Die einfache Implementierung aufgrund der geringen Größe und Tragbarkeit der Touch Arrays ermöglicht die Prüfung antimikrobieller Oberflächen unter verschiedenen Bedingungen.
Influence of Pregnancy Intention on Postpartum Contraceptive Choice at an Urban Academic Medical Center
Authors: St John Meghan , Sullivan Kirby , DeFranco Emily A. , Kelly Elizabeth
Published: May 2024

Objective This study aimed to describe postpartum contraception preferences in the context of pregnancy intention (PI).

Study Design A prospective cohort study analyzing postpartum contraceptive choice (PCC) in 431 postpartum women who delivered at a single academic medical center. PCC in women with an unintended or mistimed pregnancy was compared to contraceptive choice in women with an intended pregnancy using the adapted National Survey of Family Growth categorization. Mistimed and unintended pregnancies were grouped for analysis. Generalized linear modeling estimated the relative influence of PI on PCC adjusting for maternal age, race, and parity.

Results Nearly three out of four (71.9%) pregnancies were mistimed or unintended. These pregnancies were more likely in women who were non-Hispanic Black (62.3%), unmarried (86.3%), 18 to 24 years (51.3%), and insured by Medicaid or Medicare (82.1%), compared to women with an intended pregnancy, p-value <0.001. Women with mistimed or unintended pregnancy were 83% more likely to choose highly effective, user-independent methods compared to any other or no method, adjusted relative risk (aRR) = 1.83 (95% confidence interval [CI]: 1.36, 2.47), and more likely to desire voluntary sterilization, aRR = 2.70 (95% CI: 1.58, 4.59). Additionally, women with these pregnancies were 56% more likely to use user-independent methods compared to user-dependent methods, aRR = 1.56 (95% CI: 1.18, 2.06).

Conclusion Women with mistimed or unintended pregnancies are 83% more likely to choose highly effective postpartum contraception or voluntary sterilization, and thus initiatives are necessary to increase access and affordability to these methods before hospital discharge after delivery.

Key Points
Asymmetric Access to Chiral Sulfinyl Compounds as Bioisosteres of Carbonyl Compounds
Authors: Liu Gang , Wu Jie , Wang Chenxin , Wu Xinyu , Huang Jiapian
Published: May 2024

The sulfinyl group, as one of the bioisosteres of carbonyl groups, attracts considerable attention in the field of synthetic chemistry. In particular, the asymmetric construction of chiral sulfinyl compounds and their derivatives remains in the early stages of development. Sulfinyl compounds mainly include sulfoxides, sulfinate esters and sulfinamides, according to the different functional groups connected to the sulfur atom. This Review summarizes the fascinating recent progress made over the past decade on the asymmetric synthesis of enantiopure sulfinyl derivatives.

1 Introduction

2 Asymmetric Synthesis of Chiral Sulfoxides

3 Asymmetric Synthesis of Chiral Sulfinate Esters

4 Asymmetric Synthesis of Chiral Sulfinamides

5 Conclusion and Outlook
Benzothiazole-Directed Enantioselective Borylation of Secondary Benzylic C–H Bonds Using Iridium Catalysis
Authors: Chen Lili , Xu Senmiao , Xie Liang-Jun
Published: May 2024

Reported here is the iridium-catalyzed regio- and enantio­selective secondary benzylic C–H borylation using benzothiazole as the directing group. Various monosubstituted 2-arylalkylbenzo[d]thiazole were well-tolerated, affording the corresponding products in moderate to good yields with good enantioselectivity. The C–B bond in one boryl­ated product could undergo stereospecific transformations to form a series of C–C and C–heteroatom bonds.
Polymicrogyria, Cobblestone Malformations, and Tubulin Mutation (Overmigration beyond Pial Limiting Membrane): Diagnosis, Treatment, and Rehabilitation Approach
Authors: Lo Bianco Manuela , Fichera Valeria , Zanghì Antonio , Praticò Andrea D. , Falsaperla Raffaele , Vecchio Michele , Marino Francesco , Palmucci Stefano , Belfiore Giuseppe , Foti Pietro , Polizzi Agata
Published: May 2024

Polymicrogyria, cobblestone malformations, and tubulinopathies constitute a group of neuronal migration abnormalities beyond the pial limiting membrane. Their etiopathogenesis remains unclear, with proposed environmental and genetic factors, including copy number variations and single-gene disorders, recently categorized.

Polymicrogyria features numerous small circumvolutions separated by large, shallow grooves, often affecting the perisylvian cortex with various presentations. Clinical manifestations vary depending on lesion degree, extent, and location, commonly including epilepsy, encephalopathies, spastic tetraparesis, mental retardation, and cortical function deficits.

Cobblestone malformations exhibit a Roman-like pavement cortex, affecting both hemispheres symmetrically due to disruption of the glia limitans, frequently linked to glycosyltransferase gene mutations. Classified separately from lissencephaly type II, they are associated with congenital muscular dystrophy syndromes such as Fukuyama congenital muscular dystrophy, Walker–Warburg syndrome, and muscle–eye–brain disease.

Tubulinopathies encompass diverse cerebral malformations resulting from α-tubulin isotype gene variants, exhibiting a wide clinical spectrum including motor/cognitive impairment, facial diplegia, strabismus, and epilepsy.

Diagnosis relies on magnetic resonance imaging (MRI) with age-specific protocols, highlighting the gray–white junction as a polymicrogyria marker, though neonatal diagnosis may be challenging due to technical and brain maturity issues.

To date, no effective treatments are available and management include physiotherapy, speech and language therapy, and vision training program for oculomotor disabilities; antiepileptic drugs are commonly necessary, and most severe forms usually require specific nutritional support.
Spectrum of Resistance Mechanisms to ALK TKIs in NSCLC: Largest Single-Center Experience from India
Authors: Batra Ullas , Nathany Shrinidhi , Sharma Mansi , P. Amrith B. , Vaidya Shriya , Mattoo Sakshi , Kumar Dushyant , Mehta Anurag
Published: May 2024

Introduction Anaplastic lymphoma kinase (ALK) rearranged non-small cell lung carcinoma (NSCLC) has emerged as a distinct entity with growing number of potent ALK tyrosine kinase inhibitors (TKIs). Despite showing durable responses and promising survival rates, resistance to these ensue. This is the largest series of repeat biopsies from patients of ALK-positive NSCLC progressing on ALK-directed therapy from this part of the world. Using a combinatorial approach of genomics and histology, we describe the spectrum of various resistance mechanisms encountered.

Methods This is a cross-sectional study recruiting ALK-positive NSCLC cases who have progressed on any line ALK TKI and have undergone repeated biopsies followed by genomic sequencing by next-generation sequencing (NGS).

Results Thirty-two ALK-positive NSCLC patients progressed on TKI were enrolled. Median age was 53 years (range: 36–75 years) with a male predilection (male:female 1.3:1). Twenty-seven (84.4%) cases harbored an additional resistance mechanism. Eighteen of these harbored an on-target ALK alteration, with L1196M gatekeeper mutation being the most common, in 11 cases, and G1202 alteration in 3 cases. In 9 cases an off-target alteration was detected, the most frequent being TP53 mutation in 8 cases, KRAS mutation in 4 cases and MET amplification in 3 cases. Four patients underwent sequential NGS testing and allele frequency changes in ALK fusion and resistance mechanisms were demonstrated. Sixteen patients have been offered lorlatinib therapy, the median progression-free survival of which has not yet been reached.

Conclusion This is the largest series depicting ALK resistance mechanisms from a single center to date. The SPACEWALK study which demonstrated ALK TKI resistance mechanisms using plasma-based genotyping was a multicentric study. The spectrum encountered in this study is distinct from the rest of the world, thus highlighting heterogeneity within ALK-rearranged tumors. Comprehensive clinical evaluation at disease progression coupled with NGS-based genotyping will pave the way for lucid understanding of disease biology, thus aiding in the institution of optimal therapy.
2 Cross-Dehydrogenative Coupling: Development and Perspectives
Authors: Huang C.-Y. , Kang H. , Li C.-J.
Published: May 2024

Cross-coupling transformations are a fundamental and expeditious tool for building up molecular complexity. Among the possible strategies, cross-dehydrogenative coupling (CDC) has received great attention in the past two decades, not only for its high step- and atom-economy, but also for the diverse feedstock availability. This article discusses the advantages of CDC, the practical applications, and some perspectives of this rising field in order to provide readers with an introduction to this flourishing area in organic synthesis.
5 (Het)Arene/(Het)Arene Cross-Dehydrogenative Coupling for C(sp2)—C(sp2) Bond Formation
Authors: Jha N. , Kapur M.
Published: May 2024

Among the various strategies for C—C bond formation, cross-dehydrogenative coupling (CDC) reactions form an integral class, primarily due to their step- and atom-economic nature. With dihydrogen as the only side-product, this method couples two unmodified C—H bonds, thereby avoiding the need for prefunctionalization of substrates. This chapter focuses exclusively on transition-metal-catalyzed C(sp2)—C(sp2) bond-forming CDC reactions between arenes/hetarenes. The most viable methods, leading to the facile syntheses of biaryl scaffolds, have been assembled, thereby providing a platform for easy access to a wide variety of arene or hetarene skeletons.
9 (Het)Arene/Alkane Cross-Dehydrogenative Coupling for C(sp2)—C(sp3) Bond Formation
Authors: Iwasaki T. , Kambe N.
Published: May 2024

Introduction of alkyl groups onto arenes and hetarenes is a fundamental modification of (het)arenes and can exert significant effects on their physical, chemical, and/or biological properties. Among alkylation reactions, the cross-dehydrogenative coupling of (het)arenes with hydrocarbons through double C—H bond cleavage is a straightforward synthetic method that avoids prefunctionalization of the substrate(s). This review provides an overview of the alkylation of (het)arenes, including arenes, perfluoroarenes, and nitrogen, oxygen, and sulfur heterocycles, by hydrocarbons via cross-dehydrogenative coupling.
13 C—C Bond Formation in Flow Systems Through Cross-Dehydrogenative Coupling
Authors: Martins G. M. , Silva R. C. , Zimmer G. C. , Brocksom T. J. , de Oliveira K. T.
Published: May 2024

The development of new reaction pathways seeking to improve synthetic efficiency is a continuing necessity. In this context, the formation of C—C bonds through cross-dehydrogenative coupling has emerged as a powerful and elegant strategy in organic synthesis and, together with continuous-flow technology, new perspectives have engaged the interest of the scientific community. Continuous-flow chemistry provides new synthetic possibilities, solving problems that are common with reactions performed under batch conditions, such as long reaction times, difficulty of scale-up, reproducibility, general efficiency, and safety, among others. In this chapter, C—C bond formation in flow systems through cross-dehydrogenative coupling is described.
15 C—C Bond Formation through Cross-Dehydrogenative Coupling in Natural Product and API Synthesis
Authors: Fukuta T. , Kanai M.
Published: May 2024

This review describes cross-dehydrogenative coupling (CDC) reactions used for the synthesis of natural products and active pharmaceutical ingredients (APIs). CDC reactions generally streamline the synthesis of multifunctional molecules because they do not require preactivation or prefunctionalization of the substrates. C(sp2)—C(sp2), C(sp2)—C(sp3), and C(sp3)—C(sp3) bond-forming CDC reactions through Fujiwara–Moritani reaction, Friedel–Crafts-type reactions, Minisci-type reactions, and enolate coupling reactions are summarized.
17 C—O Bond Formation through Cross-Dehydrogenative Coupling
Authors: Miyabe H.
Published: May 2024

Dehydrogenative C—H/O—H coupling has emerged as an atom-economical strategy. This review highlights representative reactions and selected recent examples of dehydrogenative C—O bond formation. Dehydrogenative oxygenations of C(sp3)—H bonds of alkanes and C(sp2)—H bonds of arenes, alkenes, aldehydes, or imines are summarized.
11 Cross-Dehydrogenative Coupling for C(sp3)—C(sp3) Bond Formation
Authors: Li X. , Song Q.
Published: May 2024

Cross-dehydrogenative coupling (CDC) is regarded as the most straightforward approach to forge a C(sp3)—C(sp3) bond. In this process, two C(sp3)—H bonds are transformed into a C(sp3)—C(sp3) bond, either with or without a sacrificial oxidant, or under a photo- or electrocatalytic system. Several reaction modes, including both non-enantioselective and enantioselective, have been developed for the preparation of a series of structurally different organic compounds. In this review, the most useful reaction systems for cross-dehydrogenative coupling between C(sp3)—H bonds, including enantioselective versions, are presented.
12 Electrochemical C—C Bond Formation through Cross-Dehydrogenative Coupling
Authors: Arun V. , Saha S. K. , De Sarkar S.
Published: May 2024

Cross-dehydrogenative coupling is a challenging strategy that continues to evolve, as it avoids the typical requirements of prefunctionalization of substrates for C—C coupling transformations. Electrooxidation can be applied in dehydrogenative processes as a replacement for redox reagents, thereby making the protocol greener and more sustainable. In this review, recent developments in electrochemical dehydrogenative couplings for the construction of C—C bonds are summarized. There is a particular focus on the functionalization of C(sp2) and C(sp3) positions to access heterocyclic scaffolds, conjugated systems, and annulated frameworks.
14 C—C Bond Formation in Water through Cross-Dehydrogenative Coupling
Authors: Adak L. , Ghosh T. , Ranu B. C.
Published: May 2024

The development of efficient procedures for useful reactions continues to be of great importance in organic synthesis. In the past decades, cross-dehydrogenative coupling (CDC) has been extensively investigated as one of the most efficient and sustainable synthetic approaches for the construction of C—C (or C—X) bonds. Cross-dehydrogenative coupling can be applied to produce new C—C or C—X bonds (X = N, O, S, P) under oxidative conditions, without prefunctionalization of reactants, by efficient and simple routes. Conventionally, these reactions have generally been performed in dry organic solvents as it is thought that water molecules may react with the reaction intermediates and catalytic species, hindering catalytic processes. However, in recent years, water has been successfully used as an alternative reaction medium for efficient cross-dehydrogenative coupling reactions. The obvious advantages of using water are its abundance, non-flammability, non-toxicity, and environmental friendliness. This review highlights recent progress in the formation of C—C bonds through cross-dehydrogenative coupling in water.
16 C—N Bond Formation through Cross-Dehydrogenative Coupling
Authors: Chowdhury D. , Koner M. , Baidya M.
Published: May 2024

Amines are versatile building blocks in organic chemistry, with widespread occurrence in natural products, agrochemicals, and functional materials. Traditional methods for the synthesis of amines have been largely replaced by cross-dehydrogenative C—N bond formation processes, which formally generate hydrogen as the byproduct and obviate the need for prefunctionalized substrates. Consequently, such reactions are extremely attractive from a viewpoint of green chemistry and sustainability. This chapter deals with cross-dehydrogenative C—N bond formation reactions via strategies based on transition-metal-catalyzed directed C—H activation and visible-light-mediated coupling.
Integrated information decomposition unveils major structural traits of in silico and in vitro neuronal networks
Authors: Menesse Gustavo , Houben Akke Mats , Soriano Jordi , Torres Joaquín J.
Published: May 2024

The properties of complex networked systems arise from the interplay between the dynamics of their elements and the underlying topology. Thus, to understand their behavior, it is crucial to convene as much information as possible about their topological organization. However, in large systems, such as neuronal networks, the reconstruction of such topology is usually carried out from the information encoded in the dynamics on the network, such as spike train time series, and by measuring the transfer entropy between system elements. The topological information recovered by these methods does not necessarily capture the connectivity layout, but rather the causal flow of information between elements. New theoretical frameworks, such as Integrated Information Decomposition (Φ-ID), allow one to explore the modes in which information can flow between parts of a system, opening a rich landscape of interactions between network topology, dynamics, and information. Here, we apply Φ-ID on in silico and in vitro data to decompose the usual transfer entropy measure into different modes of information transfer, namely, synergistic, redundant, or unique. We demonstrate that the unique information transfer is the most relevant measure to uncover structural topological details from network activity data, while redundant information only introduces residual information for this application. Although the retrieved network connectivity is still functional, it captures more details of the underlying structural topology by avoiding to take into account emergent high-order interactions and information redundancy between elements, which are important for the functional behavior, but mask the detection of direct simple interactions between elements constituted by the structural network topology.
Product-specific reaction kinetics in continuous uniform supersonic flows probed by chirped-pulse microwave spectroscopy
Authors: Guillaume Théo , Hays Brian M. , Gupta Divita , Cooke Ilsa R. , Abdelkader Khedaoui Omar , Hearne Thomas S. , Drissi Myriam , Sims Ian R.
Published: May 2024

Experimental studies of the products of elementary gas-phase chemical reactions occurring at low temperatures (<50 K) are very scarce, but of importance for fundamental studies of reaction dynamics, comparisons with high-level quantum dynamical calculations, and, in particular, for providing data for the modeling of cold astrophysical environments, such as dense interstellar clouds, the atmospheres of the outer planets, and cometary comae. This study describes the construction and testing of a new apparatus designed to measure product branching fractions of elementary bimolecular gas-phase reactions at low temperatures. It combines chirped-pulse Fourier transform millimeter wave spectroscopy with continuous uniform supersonic flows and high repetition rate laser photolysis. After a comprehensive description of the apparatus, the experimental procedures and data processing protocols used for signal recovery, the capabilities of the instrument are explored by the study of the photodissociation of acrylonitrile and the detection of two of its photoproducts, HC3N and HCN. A description is then given of a study of the reactions of the CN radical with C2H2 at 30 K, detecting the HC3N product, and with C2H6 at 10 K, detecting the HCN product. A calibration of these two products is finally attempted using the photodissociation of acrylonitrile as a reference process. The limitations and possible improvements in the instrument are discussed in conclusion.
Virtual photon exchange vs electron transfer in interparticle Coulombic electron capture
Authors: Graves Vincent , Šenk Jan , Kolorenč Přemysl , Sisourat Nicolas , Gorfinkiel Jimena D.
Published: May 2024

We have investigated Interparticle Coulombic Electron Capture (ICEC) using an ab initio approach for two systems, H+ + H2O and H + H2O+. In this work, we have determined the contribution of virtual photon exchange and electron transfer to the total ICEC cross section as a function of the distance between the charged and neutral particles. Furthermore, we have shown that the relative orientation of the electron acceptor and neighbor systems affects the magnitude of the ICEC cross sections by at least two orders at relatively small distances. This geometry dependence, present even for distances as large as 10 a0, is due to the electron transfer contribution. The relative magnitude of each contribution to ICEC seems to depend on the system studied. By replacing the projectile electron with a positron, we have confirmed that electron transfer also takes place in positron collisions and that the charge of the projectile has a noticeable effect on the process, particularly at low scattering energies.
Bandgap formation in topological metamaterials with spatially modulated resonators
Authors: LeGrande Joshua , Malla Arun , Bukhari Mohammad , Barry Oumar
Published: May 2024

Within the field of elastic metamaterials, topological metamaterials have recently received much attention due to their ability to host topologically robust edge states. Introducing local resonators to these metamaterials also opens the door for many applications such as energy harvesting and reconfigurable metamaterials. However, the interactions between phenomena from local resonance and modulation patterning are currently unknown. This work fills that gap by studying multiple cases of spatially modulated metamaterials with local resonators to reveal the mechanisms behind bandgap formation. Their dispersion relations are determined analytically for infinite chains and validated numerically using eigenvalue analysis. The inverse method is used to determine the imaginary wavenumber components from which each bandgap is characterized by its formation mechanism. The topological nature of the bandgaps is also explored through calculating the Chern number and integrated density of states. The band structures are obtained for various sources of modulation as well as multiple resonator parameters to illustrate how both local resonance and modulation patterning interact together to influence the band structure. Other unique features of these metamaterials are further demonstrated through the mode shapes obtained using the eigenvectors. The results reveal a complex band structure that is highly tunable, and the observations given here can be used to guide designers in choosing resonator parameters and patterning to fit a variety of applications.
Prospects for memristors with hysteretic memristance as so-far missing core hardware element for transfer-less data computing and storage
Authors: Schmidt Heidemarie
Published: May 2024

We like and need Information and Communication Technologies (ICTs) for data processing. This is measurable in the exponential growth of data processed by ICT, e.g., ICT for cryptocurrency mining and search engines. So far, the energy demand for computing technology has increased by a factor of 1.38 every 10 years due to the exponentially increasing use of ICT systems as computing devices. Energy consumption of ICT systems is expected to rise from 1500 TWh (8% of global electricity consumption) in 2010 to 5700 TWh (14% of global electricity consumption) in 2030 [A. S. G. Andrae, Eng. Appl. Sci. Lett. 3, 19–31 (2020)]. A large part of this energy is required for the continuous data transfer between separated memory and processor units, which constitute the main components of ICT computing devices in von-Neumann architecture. This, at the same time, massively slows down the computing power of ICT systems in von-Neumann architecture. In addition, due to the increasing complexity of artificial intelligence (AI) compute algorithms, since 2010, the AI training compute time demand for computing technology has increased tenfold every year, for example, from 1 × 10−6 to 1 × 10+4 Petaflops/day in the period from 2010 to 2020 [J. Wang, see https://ark-invest.com/articles/analyst-research/ai-training/ for information about the cost to train an AI interference system (2020)]. It has been theoretically predicted that ICT systems in the neuromorphic computer architecture will circumvent all of this through the use of merged memory and processor units. However, the core hardware element for this has not yet been realized so far. In this work, we discuss the perspectives for non-volatile resistive switches with hysteretic memristance as the core hardware element for merged memory and processor units in neuromorphic computers.
Frequency-polarization multiplexing reflective metasurface for orbital angular momentum generation
Authors: Jiang Yuying , Li Shuying , Chen Xinlei , Gu Changqing , Li Zhuo
Published: May 2024

Frequency-polarization multiplexing metasurfaces (FPMMSs) capable of generating vortex beams carrying orbital angular momentum (OAM) have facilitated the actualization of high information capacity in optical and microwave communication. However, poor frequency controllability and the deficiency of theoretical methodology for frequency modulation of meta-atom remain challenges for existing FPMMSs with orthogonal linear polarization. In this work, a strategy to customize the operating band of the “I”-shaped meta-atom (ISMA) based on phase analysis of the equivalent circuit is proposed. A frequency modulation factor is introduced to adjust the operating band of the ISMA over a wide range based on the relationships between element geometry parameters, capacitance and inductance values in the equivalent circuit model, and the reflected phase of ISMA-type meta-atom. Then, a dual-band dual-polarized meta-atom is proposed by placing subunits operating at different bands cross-orthogonally, allowing the subunits to modulate the phase independently. A dual-band dual-polarized dual-mode OAM beam generator is designed and constructed as a proof-of-concept to verify the methodology. The measured results are in excellent agreement with the simulations. The proposed methodology for customizing frequencies establishes the groundwork for the implementation of OAM-based FPMMSs for secure and high-capacity communication in 6G massive-MIMO systems.
3D positional metrology of a virus-like nanoparticle with topologically structured light
Authors: Wang Yu , Chan Eng Aik , Rendón-Barraza Carolina , Shen Yijie , Plum Eric , MacDonald Kevin F. , Ou Jun-Yu , Zheludev Nikolay I.
Published: May 2024

Locating and identifying viruses in in vitro optical measurements is desirable for disease control; however, the sub-diffraction-limit dimensions and low refractive index contrast of viruses make this challenging. Here, we introduce a 3D positional nanometrology for a virus-like 100 nm polystyrene sphere that can reveal the position of the nanoparticle with deeply sub-wavelength accuracy using topologically structured light illumination and machine learning. Scattering of topologically structured light is highly sensitive to the position of a nano-object. Exploiting this, our experiments demonstrate deeply sub-wavelength (λ) precision reaching 5 nm (λ/91). Our findings indicate a route toward label-free in vitro nanometrology of viruses and similar nano-objects with precision far beyond the Abbe–Rayleigh diffraction limit.
Micro-jetting: Areal density calculation from a triangular groove
Authors: Soulard Laurent , Durand Olivier , Burie Jean-René , Babilotte Killian
Published: May 2024

We present a method for calculating the mass ejected during the reflection of a shock wave on a triangular groove. This calculation is based on the combination of two models taken from the literature, BMPT-2, on the one hand, for the calculation of the velocity and density of the jet, and fragmentation zone propagation (FZP ) on the other hand, for the calculation of the ejected mass, certain parameters required for FZP being determined by BMPT-2. Compared with previous work, FZP has been extended to deal with the various stages of jet formation. The approach was first evaluated on tin using a large-scale molecular dynamics simulation. This first step validated the overall phenomenology and the associated theoretical tools, and enabled us to propose a procedure for adjusting FZP. Next, we used the BMPT-2/FZP combination to analyze ejected mass measurement experiments using Asay foil. The areal mass curves are well reproduced with few parameters, showing that there is no inconsistency between BMPT-2/FZP and the experiments. Finally, a more detailed analysis of the results obtained enables us to set the limits of the jet thickness at the moment of rupture, and to propose a simple analytical form of its profile compatible with the model used.
Redox potentials in ionic liquids: Anomalous behavior?
Authors: Renfro Chloe A. , Hymel John H. , McDaniel Jesse G.
Published: May 2024

Redox potentials depend on the nature of the solvent/electrolyte through the solvation energies of the ionic solute species. For concentrated electrolytes, ion solvation may deviate significantly from the Born model predictions due to ion pairing and correlation effects. Recently, Ghorai and Matyushov [J. Phys. Chem. B 124, 3754–3769 (2020)] predicted, on the basis of linear response theory, an anomalous trend in the solvation energies of room temperature ionic liquids, with deviations of hundreds of kJ/mol from the Born model for certain size solutes/ions. In this work, we computationally evaluate ionic solvation energies in the prototypical ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM/BF4), to further explore this behavior and benchmark several of the approximations utilized in the solvation energy predictions. For comparison, we additionally compute solvation energies within acetonitrile and molten NaCl salt to illustrate the limiting behavior of purely dipolar and ionic solvents. We find that the overscreening effect, which results from the inherent charge oscillations of the ionic liquid, is substantially reduced in magnitude due to screening from the dipoles of the molecular ions. Therefore, for the molten NaCl salt, for which the ions do not have permanent dipoles, modulation of ionic solvation energies from the overscreening effect is most significant. The conclusion is that ionic liquids do indeed exhibit unique solvation behavior due to peak(s) in the electrical susceptibility caused by the ion shell structure; redox potential shifts for BMIM/BF4 are of more modest order ∼0.1 V, but may be larger for other ionic liquids that approach molten salt behavior.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: May 2024

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials that supersede earlier data or suggest new research applications.
Limited intraspecific variation in drought resistance along a pronounced tropical rainfall gradient
Authors: Comita Liza S. , Jones F. Andrew , Manzané-Pinzón Eric J. , Álvarez-Cansino Leonor , Cerón-Souza Ivania , Contreras Blexein , Jaén-Barrios Nelson , Ferro Natalie , Engelbrecht Bettina M. J.
Published: May 2024

Assessing within-species variation in response to drought is crucial for predicting species’ responses to climate change and informing restoration and conservation efforts, yet experimental data are lacking for the vast majority of tropical tree species. We assessed intraspecific variation in response to water availability across a strong rainfall gradient for 16 tropical tree species using reciprocal transplant and common garden field experiments, along with measurements of gene flow and key functional traits linked to drought resistance. Although drought resistance varies widely among species in these forests, we found little evidence for within-species variation in drought resistance. For the majority of functional traits measured, we detected no significant intraspecific variation. The few traits that did vary significantly between drier and wetter origins of the same species all showed relationships opposite to expectations based on drought stress. Furthermore, seedlings of the same species originating from drier and wetter sites performed equally well under drought conditions in the common garden experiment and at the driest transplant site. However, contrary to expectation, wetter-origin seedlings survived better than drier-origin seedlings under wetter conditions in both the reciprocal transplant and common garden experiment, potentially due to lower insect herbivory. Our study provides the most comprehensive picture to date of intraspecific variation in tropical tree species’ responses to water availability. Our findings suggest that while drought plays an important role in shaping species composition across moist tropical forests, its influence on within-species variation is limited.
The transformation of the rotational energy of a Kerr black hole
Authors: Zhang Shu-Rui , Prakapenia Mikalai
Published: May 2024

This paper analyzes the feedback of the rotational energy extraction from a Kerr black hole (BH) by the ‘ballistic method’, i.e. the test particle decay in the BH ergosphere pioneered by Roger Penrose. The focus is on the negative energy counterrotating particles (which can be massive or massless) going in towards the horizon, and the feedback on the BH irreducible mass is assessed. Generally, the change in irreducible mass is a function of the conserved quantities of the particle. For an extreme Kerr BH and in the limit

μ
1

/

M
→
0

, all the reduced transformable energy goes into the irreducible mass (i.e.

Δ

M
irr

/

|

E
1

|

→
∞

), resulting in high irreversibility. The amount of extracted energy from the BH using test particles is much lower than the change of transformable energy. For non-extreme Kerr BHs, the effective potential of particle motion on the equatorial plane in Kerr spacetime is analyzed, and it is demonstrated that the Penrose process can only be undergone by BHs with a dimensionless spin

a
^

>
1

/

2

if the decay point coincides with the turning point. Based on that, the lower limit of the change in irreducible mass is provided as a function of the dimensionless spin of the BH. The significance of the increase in the irreducible mass of the BH during the energy extraction process is generally and concisely illustrated by introducing the concept of transformable energy of the BH. The feedback from the Penrose process on the irreducible mass demonstrates the irreversibility of energy extraction and highlights that the total amount of energy that can be extracted from a BH is less than previously anticipated.
Giant enhancement of coercivity in β-Ni(OH)2 decorated Ti3C2T
x
MXene nanosheets
Authors: Debnath Anup , Bera Sumanta , Mahapatra Gouranga , Kapuria Arijit , Saha Shyamal K
Published: May 2024

Ti3C2T
x
MXenes are of great interest due to their high conductivity, easy synthesis and unique functional properties. Functionalisation and structural engineering are essential for various applications because of their dramatic influences on different chemical and physical properties. Therefore, understanding the mechanism of the etching reaction of Ti3C2T
x
from its parent MAX phase is crucial. The structural details also need to be understood for application in different practical devices. In this study, 2D Ti3C2T
x
sheets with an average thickness of 3.48 nm and lateral dimension of 5.5 µm were synthesised by removing Al layers from the Ti3AlC2 MAX phase. The step-by-step etching mechanism was analysed with the help of Rietveld refinement of the powder x-ray diffraction data. The structural details and influence of different functional groups on the surface were also studied using transmission electron microscopy, x-ray photoelectron spectroscopy, and Raman spectroscopy. The magnetic behaviour and magnetic interaction of bare 2D Ti3C2T
x
decorated with β-Ni(OH)2 nanosheets on its surface was studied. For the bare 2D Ti3C2T
x
MXene sheets, a weak ferrimagnetic ordering with negligible coercivity was found. However, the β-Ni(OH)2-decorated Ti3C2T
x
MXene sheets exhibit strong ferrimagnetic ordering with a sufficiently large coercivity of 0.2 T at 2 K and a transition temperature of 246 K. The generation of this interfacial ferrimagnetism is discussed in light of the interfacial charge transfer originating from d-p mixing. These 2D magnets generated at the interface could be useful for application in different spintronic devices.
Synthesizable manganese nitride with giant magnetocrystalline anisotropy energy
Authors: Yang Ze-Jin
Published: May 2024

Using a crystal structure prediction program (CALYPSO), we found many experimentally synthesizable low-energy structures with perfect or nearly perfect easy-axis magnetocrystalline anisotropy energy (MAE) in manganese nitride, including MnN, Mn2N, Mn3N2, Mn5N2, and Mn4N, respectively, which are the stoichiometries more frequently studied by experimental researchers. MnN (

I

4
―

2
d

) shows giant MAE with values of E
001 = 1006, E
010 = 0, and E
100 = 920 μeV/atom (same hereafter in the abstract for the MAE unit). Mn3N2 (P42/mmc) shows perfect easy-axis MAE, whose E
010 = E
100 = 12, whereas Ibam has a nearly perfect easy-axis MAE with values of E
001 = 324 and E
010 = 345. Mn2N has four almost totally perfect easy-axis MAE structures, including P4/mmm (E
001 = 249, E
100 = 250), Pccm (E
001 = E
100 = 62), P4/nmm (E
001 = 58, E
100 = 60), and Imma (E
001 = 108, E
100 = 109). Mn4N has one perfect structure, I4/mmm (E
001 = E
100 = 169), and two nearly perfect structures, including Fmmm (E
001 = 126, E
010 = 121) as well as I4/mmm (E
010 = 127, E
100 = 133). Too many valuable structures deserve to be further studied by both theoretical and experimental scientists regarding their other magnetic properties except for the present MAE. The present study might attract close attention to several of these compounds.
The Xe isotope nuclear resonance frequency shift of NMR angular velocity sensors due to transverse gradient magnetic fields
Authors: Jie Shaofeng , Liu Zhanchao
Published: May 2024

The nuclear magnetic resonance (NMR) angular velocity sensor detects angular velocity by measuring the shift in the nuclear spin precession frequency, which is of fundamental interest. Recent studies have revealed the parameter dependency of nuclei frequency shifts induced by non-uniformly distributed polarized pump beams, temperature, and magnetic field properties. In this study, we investigated the effect of the linear transverse gradient magnetic field on the frequency ratio shift of the Xe isotope nuclear resonance frequency in the NMR sensors. A theoretical analysis method was proposed based on the Fermi contact interaction in atomic polarization and the spin-diffusion relaxation of 129Xe and 131Xe nuclei. The frequency ratio shift of the Xe isotope under different x-axis gradient magnetic fields was measured experimentally. Furthermore, we eliminated the equivalent residual magnetic field through a feedback system and compensated for the original gradient magnetic field in the system, which contributed to accurately revealing the frequency shift induced by the magnetic field gradient. The results indicate that the frequency ratio shift of the Xe isotope is proportional to the strength of the second-order linear transverse gradient magnetic field. This study provides a reference for the analysis and evaluation of the presence of the gradient magnetic field in the NMR angular velocity sensor.
Time-reversibility and nonvanishing Lévy area
Authors: Gottwald Georg A , Melbourne Ian
Published: May 2024

We give a complete description and clarification of the structure of the Lévy area correction to Itô/Stratonovich stochastic integrals arising as limits of time-reversible deterministic dynamical systems. In particular, we show that time-reversibility forces the Lévy area to vanish only in very specific situations that are easily classified. In the absence of such obstructions, we prove that there are no further restrictions on the Lévy area and that it is typically nonvanishing and far from negligible.