bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct codes for environment structure and symmetry in postrhinal and retrosplenial cortices
Authors: LaChance Patrick A. , Hasselmo Michael E.
Published: September 2024

Complex sensory information arrives in the brain from an animal’s first-person (‘egocentric’) perspective. However, animals can efficiently navigate as if referencing map-like (‘allocentric’) representations. The postrhinal (POR) and retrosplenial (RSC) cortices are thought to mediate between sensory input and internal maps, combining egocentric representations of physical cues with allocentric head direction (HD) information. Here we show that neurons in the POR and RSC of female Long-Evans rats are tuned to distinct but complementary aspects of local space. Egocentric bearing (EB) cells recorded in square and L-shaped environments reveal that RSC cells encode local geometric features, while POR cells encode a more global account of boundary geometry. Additionally, POR HD cells can incorporate egocentric information to fire in two opposite directions with two oppositely placed identical visual landmarks, while only a subset of RSC HD cells possess this property. Entorhinal grid and HD cells exhibit consistently allocentric spatial firing properties. These results reveal significant regional differences in the neural encoding of spatial reference frames.
Interferometric excitation fluorescence lifetime imaging microscopy
Authors: Malý Pavel , Strachotová Dita , Holoubek Aleš , Heřman Petr
Published: September 2024

Fluorescence lifetime imaging microscopy (FLIM) is a well-established technique with numerous imaging applications. Yet, one of the limitations of FLIM is that it only provides information about the emitting state. Here, we present an extension of FLIM by interferometric measurement of fluorescence excitation spectra. Interferometric Excitation Fluorescence Lifetime Imaging Microscopy (ixFLIM) reports on the correlation of the excitation spectra and emission lifetime, providing the correlation between the ground-state absorption and excited-state emission. As such, it extends the applicability of FLIM and removes some of its limitations. We introduce ixFLIM on progressively more complex systems, directly compare it to standard FLIM, and apply it to quantitative resonance energy transfer imaging from a single measurement.
Carbon isotope budget indicates biological disequilibrium dominated ocean carbon storage at the Last Glacial Maximum
Authors: Omta Anne Willem , Follett Christopher L. , Lauderdale Jonathan M. , Ferrari Raffaele
Published: September 2024

Understanding the causes of the  ~90 ppmv atmospheric CO2 swings between glacial and interglacial climates is an important open challenge in paleoclimate research. Although the regularity of the glacial-interglacial cycles hints at a single driving mechanism, Earth System models require many independent physical and biological processes to explain the full observed CO2 signal. Here we show that biologically sequestered carbon in the ocean can explain an atmospheric CO2 change of 75 ± 40 ppmv, based on a mass balance calculation using published carbon isotopic measurements. An analysis of the carbon isotopic signatures of different water masses indicates similar regenerated carbon inventories at the Last Glacial Maximum and during the Holocene, requiring that the change in carbon storage was dominated by disequilibrium. We attribute the inferred change in carbon disequilibrium to expansion of sea-ice or change in the overturning circulation.
Small-molecule properties define partitioning into biomolecular condensates
Authors: Ambadi Thody Sabareesan , Clements Hanna D. , Baniasadi Hamid , Lyon Andrew S. , Sigman Matthew S. , Rosen Michael K.
Published: September 2024

Biomolecular condensates regulate cellular function by compartmentalizing molecules without a surrounding membrane. Condensate function arises from the specific exclusion or enrichment of molecules. Thus, understanding condensate composition is critical to characterizing condensate function. Whereas principles defining macromolecular composition have been described, understanding of small-molecule composition remains limited. Here we quantified the partitioning of ~1,700 biologically relevant small molecules into condensates composed of different macromolecules. Partitioning varied nearly a million-fold across compounds but was correlated among condensates, indicating that disparate condensates are physically similar. For one system, the enriched compounds did not generally bind macromolecules with high affinity under conditions where condensates do not form, suggesting that partitioning is not governed by site-specific interactions. Correspondingly, a machine learning model accurately predicts partitioning using only computed physicochemical features of the compounds, chiefly those related to solubility and hydrophobicity. These results suggest that a hydrophobic environment emerges upon condensate formation, driving the enrichment and exclusion of small molecules.
Exploring the potential of 5G uplink communication: Synergistic integration of joint power control, user grouping, and multi-learning Grey Wolf Optimizer
Authors: Sikkanan Sobana , Kumar Chandrasekaran , Manoharan Premkumar , Ravichandran Sowmya
Published: September 2024

Non-orthogonal Multiple Access (NOMA) techniques offer potential enhancements in spectral efficiency for 5G and 6G wireless networks, facilitating broader network access. Central to realizing optimal system performance are factors like joint power control, user grouping, and decoding order. This study investigates power control and user grouping to optimize spectral efficiency in NOMA uplink systems, aiming to reduce computational difficulty. While previous research on this integrated optimization has identified several near-optimal solutions, they often come with considerable system and computational overheads. To address this, this study employed an improved Grey Wolf Optimizer (GWO), a nature-inspired metaheuristic optimization method. Although GWO is effective, it can sometimes converge prematurely and might lack diversity. To enhance its performance, this study introduces a new version of GWO, integrating Competitive Learning, Q-learning, and Greedy Selection. Competitive learning adopts agent competition, balancing exploration and exploitation and preserving diversity. Q-learning guides the search based on past experiences, enhancing adaptability and preventing redundant exploration of sub-optimal regions. Greedy selection ensures the retention of the best solutions after each iteration. The synergistic integration of these three components substantially enhances the performance of the standard GWO. This algorithm was used to manage power and user-grouping in NOMA systems, aiming to strengthen system performance while restricting computational demands. The effectiveness of the proposed algorithm was validated through numerical evaluations. Simulated outcomes revealed that when applied to the joint challenge in NOMA uplink systems, it surpasses the spectral efficiency of conventional orthogonal multiple access. Moreover, the proposed approach demonstrated superior performance compared to the standard GWO and other state-of-the-art algorithms, achieving reduced system complexity under identical constraints.
Predicting prognosis for epithelial ovarian cancer patients receiving bevacizumab treatment with CT-based deep learning
Authors: Huang Xiaoyu , Huang Yong , Liu Kexin , Zhang Fenglin , Zhu Zhou , Xu Kai , Li Ping
Published: September 2024

Epithelial ovarian cancer (EOC) presents considerable difficulties in prognostication and treatment strategy development. Bevacizumab, an anti-angiogenic medication, has demonstrated potential in enhancing progression-free survival (PFS) in EOC patients. Nevertheless, the identification of individuals at elevated risk of disease progression following treatment remains a challenging task. This study was to develop and validate a deep learning (DL) model using retrospectively collected computed tomography (CT) plain scans of inoperable and recurrent EOC patients receiving bevacizumab treatment diagnosed between January 2013 and January 2024. A total of 525 patients from three different institutions were retrospectively included in the study and divided into training set (N = 400), internal test set (N = 97) and external test set (N = 28). The model’s performance was evaluated using Harrell’s C-index. Patients were categorized into high-risk and low-risk group based on a predetermined cutoff in the training set. Additionally, a multimodal model was evaluated, incorporating the risk score generated by the DL model and the pretreatment level of carbohydrate antigen 125 as input variables. The Net Reclassification Improvement (NRI) metric quantified the reclassification performance of our optimal model in comparison to the International Federation of Gynecology and Obstetrics (FIGO) staging model. The results indicated that DL model achieved a PFS predictive C-index of 0.73 in the internal test set and a C-index of 0.61 in the external test set, along with hazard ratios of 34.24 in the training set (95% CI: 21.7, 54.1; P < 0.001) and 8.16 in the internal test set (95% CI: 2.5, 26.8; P < 0.001). The multimodal model demonstrated a C-index of 0.76 in the internal test set and a C-index of 0.64 in the external test set. Comparative analysis against FIGO staging revealed an NRI of 0.06 (P < 0.001) for the multimodal model. The model presents opportunities for prognostic assessment, treatment strategizing, and ongoing patient monitoring.
HPV-YAP1 oncogenic alliance drives malignant transformation of fallopian tube epithelial cells
Authors: He Chunbo , Lv Xiangmin , Liu Jiyuan , Ruan Jinpeng , Chen Peichao , Huang Cong , Angeletti Peter C , Hua Guohua , Moness Madelyn Leigh , Shi Davie , Dhar Anjali , Yang Siyi , Murphy Savannah , Montoute Isabelle , Chen Xingcheng , Islam Kazi Nazrul , George Sophia , Ince Tan A , Drapkin Ronny , Guda Chittibabu , Davis John S , Wang Cheng
Published: September 2024

High grade serous ovarian carcinoma (HGSOC) is the most common and aggressive ovarian malignancy. Accumulating evidence indicates that HGSOC may originate from human fallopian tube epithelial cells (FTECs), although the exact pathogen(s) and/or molecular mechanism underlying the malignant transformation of FTECs is unclear. Here we show that human papillomavirus (HPV), which could reach FTECs via retrograde menstruation or sperm-carrying, interacts with the yes-associated protein 1 (YAP1) to drive the malignant transformation of FTECs. HPV prevents FTECs from natural replicative and YAP1-induced senescence, thereby promoting YAP1-induced malignant transformation of FTECs. HPV also stimulates proliferation and drives metastasis of YAP1-transformed FTECs. YAP1, in turn, stimulates the expression of the putative HPV receptors and suppresses the innate immune system to facilitate HPV acquisition. These findings provide critical clues for developing new strategies to prevent and treat HGSOC.
A multifunctional phenylphosphinamide additive for stable flexible inverted perovskite solar cells
Authors: Liu Feihu , Geng Jidong , Zhang Wei , Dou Jie , Guo Qiyao , Duan Jialong , Tang Qunwei
Published: September 2024

The additive of phenylphosphinamide enhances the mechanical reliability of flexible inverted perovskite solar cells.
Synthesis and characterization of holmium based metal–organic frameworks
Authors: Abbas Muhammad , Degani Murtaza , Sheybani Simin , Shah Tejas , Joy Monu , Balkus Kenneth J.
Published: September 2024

Holmium based metal–organic frameworks (MOFs) are attractive due to their potential biomedical and radiotherapeutic applications.
Black titanium oxide: synthesis, modification, characterization, physiochemical properties, and emerging applications for energy conversion and storage, and environmental sustainability
Authors: Hou Xuelan , Li Yiyang , Zhang Hang , Lund Peter D. , Kwan James , Tsang Shik Chi Edman
Published: September 2024

The current synthesis methods, modifications, and characterizations of black titanium oxide (B-TiOx) as well as a nuanced understanding of its physicochemical properties and applications in green energy and environment are reviewed.
Trivial positional isomerism in ligands triggering different properties in Fe(ii)-metallopolymers; design, synthesis, and characterization
Authors: Bawa Shubham , Kumar Anil , Nim Gaurav Kumar , Bera Jayanta , Ghosh Samaresh , Sahu Satyajit , Kar Prasenjit , Bandyopadhyay Anasuya
Published: September 2024

The research investigates the impact of trivial positional isomerism in ligands on the structural and functional properties of Fe(ii)-metallopolymers, focusing on the design, synthesis, and characterization of these materials.
Rapid and accurate determination of chlorine isotopic ratios with ICP-MS/MS using O2 reaction gas
Authors: Schlieder Tyler D. , Rocco Nicole D. , di Vacri Maria Laura , Arnquist Isaac J. , Bottenus Danny , Huber Zachary , McNamara Bruce
Published: September 2024

We report a tandem ICP-MS/MS method using O2 gas for chlorine isotopic ratio determinations, with improved accuracy and increased throughput.
Investigating the extraction performance and mechanism of a multifunctional thiourea molecule for the effective removal of Ag(i) from aqueous solutions
Authors: Cao Xiaoyu , Yang Huifang , Luo Jihui , Zeng Jianxian , Cao Zhanfang , Huang Xiaoping
Published: September 2024

Highly efficient and selective extraction of silver ions from wastewater remains a formidable challenge in ensuring public health and protecting ecosystems.
High-efficiency fluoride removal using hierarchical flower-like magnesium oxide: adsorption characteristics and mechanistic insights
Authors: Zhang Liting , Cui Chenyuan , Zhu Chunmei , Gong Lu , Li Min , Xiang Siwei , Yu Bo
Published: September 2024

Efficient fluoride removal via hierarchical flower-like MgO: comprehensive adsorption characteristics and mechanistic elucidation.
One-pot synthesis of titanium isophthalate and highly active catalytic glycolysis of waste PET
Authors: Wen Ruiyang , Shen Guoliang , Zhang Meiqi , Yu Yang , Xu Shijie
Published: September 2024

The glycolysis of PET represents a pivotal approach to achieving high-value utilization following its disposal.
Continuous flow synthesis and simulation-supported investigation of tunable plasmonic gold patchy nanoparticles
Authors: Seifert Julia S. , Nees Nico , Khan Hamzah , Traoré Nabi E. , Drobek Dominik , Peukert Wolfgang , Apeleo Zubiri Benjamin , Spiecker Erdmann , Stingl Michael , Pflug Lukas , Klupp Taylor Robin N.
Published: September 2024

The scalable and tunable synthesis of anisotropic plasmonic nanoparticles based on dense gold patches grown on polystyrene nanospheres is achieved through a double T-mixer continuous flow technique and supported by FEM simulations.
Imide-yne click polymerization: a new and versatile tool for the toolbox of X-yne click polymerization
Authors: Aslanturk Oguzhan , Sagdic Gokhan , Cakmakci Emrah , Durmaz Hakan , Gunay Ufuk Saim
Published: September 2024

The imide-yne reaction is demonstrated as a new and robust method to produce a variety of polyimide-based polymers, expanding the toolkit of X-yne click polymerizations based on activated alkynes.
Efficient simulations of mobility matrices for electrolytes by applying forces
Authors: Tripathi Pramudit , Milner Scott T.
Published: September 2024

Mobility matrices from drift measurements give more accurate conductivity than diffusion measurements.
Discovery of megapolipeptins by genome mining of a Burkholderiales bacteria collection
Authors: Paulo Bruno S. , Recchia Michael J. J. , Lee Sanghoon , Fergusson Claire H. , Romanowski Sean B. , Hernandez Antonio , Krull Nyssa , Liu Dennis Y. , Cavanagh Hannah , Bos Allyson , Gray Christopher A. , Murphy Brian T. , Linington Roger G. , Eustaquio Alessandra S.
Published: September 2024

Megapolipeptins show low structural similarity to known natural products, highlighting the advantage of our Burkholderiales genomics-driven and synthetic biology-enabled pipeline to discover novel natural products.
Metal-free site-selective functionalization with cyclic diaryl λ3-chloranes: suppression of benzyne formation for ligand-coupling reactions
Authors: Patra Koushik , Dey Manas Pratim , Baidya Mahiuddin
Published: September 2024

The elusive ligand coupling reaction of cyclic λ3-chloranes was developed in three-component and two-component fashion to access a range of unsymmetrically substituted biaryl molecules in very high yields and excellent ortho-regioselectivity.
DPD simulations of anionic surfactant micelles: a critical role for polarisable water models
Authors: Hendrikse Rachel L. , Amador Carlos , Wilson Mark R.
Published: September 2024

Polarisable water models are found to influence micelle formation in dissipative particle dynamics, when compared with traditional methods. The choice of water model is shown to influence counterion condensation, stability, and micelle interactions.
Protective effect of (E)-(2,4-dihydroxy)-α-aminocinnamic acid, a hydroxy cinnamic acid derivative, in an ulcerative colitis model induced by TNBS
Authors: Rivera Antonio Astrid Mayleth , Padilla Martínez Itzia Irene , Márquez-Flores Yazmín Karina , Juárez Solano Alan Hipólito , Torres Ramos Mónica A. , Rosales Hernández Martha Cecilia
Published: September 2024

Ulcerative colitis (UC) is a multifactorial disease that causes long-lasting inflammation and ulcers in the digestive tract. UC is the most common form of inflammatory bowel disease (IBD). The current treatment for mild-to-moderate UC involves the use of 5-aminosalicylates (5-ASA), but much of this compound is unabsorbed and metabolized by N-acetylation. Several efforts have since been made to evaluate new molecules from synthetic or natural sources. Recently, it was reported that (E)-(5-chloro-2-hydroxy)-α-aminocinnamic acid (2c) and (E)-(2,4-dihydroxy)-α-aminocinnamic acid (2f) are as good or better myeloperoxidase (MPO) inhibitors and antioxidants than 5-ASA. Then, the present study aimed to evaluate the protective effects of 2c and 2f on a rat model of UC induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). The results showed that TNBS caused the induction of colonic ulcers, as well as a significant increase in MPO activity and malondialdehyde (MDA) and a decrease in glutathione (GSH) content. The administration of 2f, 2c and 5-ASA, decreased the ulcers presence, inhibited MPO peroxidation activity and MPO presence (as determined by immunofluorescence), and increased GSH and reduced MDA content. However, 2f was better than 2c and 5-ASA, then, the principal mechanism by which 2f presented a protective effect in a UC model induced by TNBS in rats is by inhibiting MPO activity and due to its antioxidant activity.
Identification of metabolite compounds on Robusta Coffee (Coffea canephora) roots related to parasitic nematodes of Prathylenchus coffeae
Authors: Arimarsetiowati Rina , Prastowo Erwin
Published: September 2024

The Prathylenchus coffeae is a significant plant-parasitic nematodes in Coffea canephora. This study examines the identification of metabolite compounds related to plant defense against parasitic nematodes by extracting C. canephora roots with n-Hexane and Gas Chromatography-Mass Spectrometry analysis of the prepared extract. Resistant coffee varieties (BP 308) and susceptible coffee varieties (BP42, BP 409, and BP 358) were used in this study. GC-MS’s data indicates the presence of fortyseven, thirty-nine, fifty, and thirty metabolite compounds in roots of BP 308, BP 42, BP 409, and BP 358, respectively. The principal component analysis (PCA) analysis using the loading plot model was conducted for reliable and accurate discrimination to identify potential metabolite compounds that serve as marker compounds and can distinguish between nematode-resistant and susceptible varieties. The results showed that each coffee variety has different metabolite compound characteristics. BP 409 was characterized by Octadecanal and Tetradecanal, BP 308 by Phenol and Guaiene and BP 358 and BP 42 by Cholest and Patchouli. This study confirmed candidate metabolite markers that differentiate coffee varieties resistant to nematode. Furthermore, the data presented may help develop a new method for detecting resistant and susceptible coffee against nematode attacks caused by Prathylenchus coffeae.
In silico characterization of somatic embryogenesis receptor like kinase (SERK) gene in oil palm (Elaeis guineensis Jacq.) and other crops
Authors: Arimarsetiowati Rina , Permatasari Galuh W. , Aksa Annisa A. , Sinta Masna M. , Saptari Rizka T. , Pratiwi Dian R. , Setiawati Yuli , Riyadi Imron , Minarsih Hayati , Prastowo Erwin , Putranto Riza A. , Sari Dini A. , Yunita Erna
Published: September 2024

The oil palm (Elaeis guineensis Jacq.) is the primary source of vegetable oil cultivation globally, and it is considered to be the most profitable oil commodity per hectare. E. guineensis Jacq. micropropagation technique can be achieved through the somatic embryogenesis process, allowing the efficient and true-to-type propagation of plants. The somatic embryogenesis (SE) mechanism describes the interaction of endogenous signals and gene reprogramming, generating signaling that develops embryo pathways. Somatic embryogenesis receptor-like kinases (SERKs) are leucine-rich repeat receptor-like kinases expressed in numerous plant signaling pathways. The SERK gene contributes an essential part in the development of embryos from single somatic cells. The characterization of SERK genes in E. guineensis Jacq. is still limited and under-explored. The objective of this research is to examine the characteristics of SERK gene by comparing the differences and similarities of SERK gene in E. guineensis Jacq. to other crops as well as their evolutionary relationship. The method was initiated by identifying nucleotide sequences from the National Center for Biotechnology Information (NCBI) database. Furthermore, it consists of the analysis of nucleotide alignment, alignment of amino acid sequences, protein analysis, protein motif function discovery and analysis of phylogenetic tree. The phylogenetic tree shows E. guineensis Jacq. has a very close relationship with Dendrobium officinale based on the SERK protein and protein motifs. These insights have implications for unraveling the long-term embryo differentiation processes of E. guineensis Jacq. and other crops during propagation by somatic embryogenesis.
Improved callus induction from immature seed of Indonesian wild banana (Musa acuminata ssp. malaccensis and rutilifes) for gene editing materials
Authors: Martanti Diyah , Handayani Tri , Talahatu Jelia Carolina , Azizi Alfia Annur Aini , Pantouw Carla Frieda , Andriyani Aviv , Sudarmonowati Enny , Hastilestari Bernadetta Rina
Published: September 2024

As a country rich in biodiversity, Indonesia possesses large numbers of wild bananas as valuable germplasm which are potential for banana breeding as they are rich of genetic variability for disease resistance, stress tolerance and other beneficial characteristics. Conventional breeding is hampered by low fertility which has caused inefficiency in producing improved varieties. Tissue culture has been applied to harness banana genetic improvement to produce massive banana plants that are identical to their parents which callus could also be used as materials for modern genetic engineering. This paper aims at investigating the response of several M. acuminata subspecies i.e. ssp. malaccensis and ssp. rutilifes in differ. Calli of these subspesies were induced from immature seeds that were inoculated using modified macronutrient and plant growth regulator. The research was designed using a completely randomized design with two factors, modified macro substances (Murashige and Skoog MS and modified Gamborg’s B5 BDS) and modification of growth regulators combination, including 2,4D, NAA, IAA and BA. Different macro elements led to different percentage of callus formed on Musa acuminata seeds. Ratio of callus production of var. malaccensis was higher on BDS media (67.49%) than on MS media (58.17%). In contrast, that of seeds of Musa acuminata var. rutilifes was higher on MS media (67.34%) than BDS media (65.29%). Growth regulator composition and concentration were also critical as media containing 2,4D (1 mg/L) + NAA (1 mg/L) and IAA (1 mg/L) were better than a combination of 2,4D (1 mg/L) + NAA (1 mg/L) and BA (1 mg/L) in callus induction in both Musa acuminata subspecies malaccensis and rutilifes (68.14% and 68.42% respectively). Meanwhile, the growth regulator treatment combination of (2,4D (1 mg/L) + NAA (1 mg/L) and IAA (1 mg/L)) has induced 68.14% calli and 68.42% of spp, malaccensis and rutilifes respectively. Therefore, for propagating banana ssp. malaccensis and rutilifes as source of materials for genetic transformation using gene editing, BDS media containing (2,4D (1 mg/L) + NAA (1 mg/L) and IAA (1 mg/L)) will be used. Embryogenic callus as the source of protoplasts would be the best regeneration procedure of transformed gene edited wild banana in the near future.
The synthesis of polymethylmethacrylate (PMMA) by miniemulsion polymerization for bone cement application: The role of anionic surfactant and co-stabilizer virgin coconut oil concentration
Authors: Simorangkir Adil Putra Natanael , Kurniawati Fitri , Prajatelistia Ekavianty , Arjasa Oka Pradipta
Published: September 2024

Polymethylmethacrylate (PMMA), a widely used polymer, finds applications in various fields, including bone cement for orthopedic surgeries. In this study, we investigate the synthesis of PMMA via miniemulsion polymerization to enhance its suitability for bone cement applications. The focus lies on understanding the impact of two critical components: anionic surfactant and co-stabilizer virgin coconut oil concentration. The miniemulsion technique offers several advantages, such as improved monomer dispersion, reduced particle size, and enhanced mechanical properties. We systematically explore the influence of different anionic surfactant concentration on the polymerization process and the resulting PMMA properties. Significantly, we evaluate the novel role of virgin coconut oil as a co-stabilizer, aiming to enhance the stability of the PMMA miniemulsion system. Our findings reveal that specific anionic surfactant concentration significantly affect the polymerization kinetics, particle size distribution, and overall PMMA properties. Furthermore, the incorporation of virgin coconut oil as a co-stabilizer demonstrates promising results in terms of miniemulsion stability and final PMMA characteristics. This research contributes valuable insights into tailoring PMMA for bone cement applications, emphasizing the importance of surfactant selection and the potential benefits of using natural co-stabilizers.
AC Zeeman effect in microfabricated surface traps
Authors: Ivory M. , Nordquist C. D. , Young K. , Hogle C. W. , Clark S. M. , Revelle M. C.
Published: September 2024

Quantum processors and atomic clocks based on trapped ions often utilize an ion’s hyperfine transition as the qubit state or frequency reference, respectively. These states are a good choice because they are insensitive in first order to magnetic field fluctuations, leading to long coherence times and stable frequency splittings. In trapped ions, however, these states are still subject to the second order AC Zeeman effect due to the necessary presence of an oscillating magnetic field used to confine the ions in a Paul trap configuration. Here, we measure the frequency shift of the 2S1/2 hyperfine transition of a 171Yb+ ion caused by the radio frequency (RF) electromagnetic field used to create confinement in several microfabricated surface trap designs. By comparing different trap designs, we show that two key design modifications significantly reduce the AC Zeeman effect experienced by the ion: (1) an RF ground layer routed directly below the entire RF electrode, and (2) a symmetric RF electrode. Both of these changes lead to better cancellation of the AC magnetic field and, thus, overall reduced frequency shifts due to the AC Zeeman effect and reduced variation across the device. These improvements enable a more homogeneous environment for quantum computing and can reduce errors for precision applications such as atomic clocks.
Carrier cooling in direct bandgap hexagonal silicon-germanium nanowires
Authors: Schouten M. F. , van Tilburg M. A. J. , van Lange V. T. , Peeters W. H. J. , Farina R. , Jansen M. M. , Vettori M. , Bakkers E. P. A. M. , Haverkort J. E. M.
Published: September 2024

Direct bandgap group IV semiconductors, like strained Ge, GeSn, or hexagonal SiGe, are considered promising for photonic integration on silicon. For group IV semiconductor lasers, it is crucial to understand the carrier cooling efficiency toward the band edges. From a fundamental perspective, a study of carrier cooling within the Γ-valley of direct bandgap group IV semiconductors is particularly interesting since the Fröhlich interaction is expected to be very weak or even absent in these materials due to the nonpolar lattice. Intravalley carrier relaxation within the Γ-valley of a nonpolar semiconductor has not been experimentally accessible before since it has always been overshadowed by intervalley processes between energetically close indirect conduction band minima. Here, we study carrier cooling in direct bandgap hexagonal silicon-germanium (hex-SiGe) nanowires, allowing us to study carrier cooling in an isolated Γ-valley that is sufficiently separated from the indirect minima. We obtain a hot carrier cooling time of 180 ps in the Γ-valley of hex-SiGe. Although the cooling is much slower than in bulk polar group III/V materials due to the absence of Fröhlich interaction, it is comparable to the cooling time in an InGaAs MQW laser structure. We conclude that carrier cooling does not inherently limit hex-SiGe to serve as a laser gain material. This result is an important insight into the field of group IV semiconductor lasers.
Active string fluids and gels formed by dipolar active Brownian particles in 3D
Authors: Kelidou Maria , Fazelzadeh Mohammad , Parage Baptiste , van Dijk Marinde , Hooijschuur Twan , Jabbari-Farouji Sara
Published: September 2024

Self-propelled particles possessing permanent magnetic dipole moments occur naturally in magnetotactic bacteria and can be built into man-made systems such as active colloids or micro-robots. Yet, the interplay between self-propulsion and anisotropic dipole–dipole interactions on dynamic self-assembly in three dimensions (3D) remains poorly understood. We conduct Brownian dynamics simulations of active dipolar particles in 3D, focusing on the low-density regime, where dipolar hard spheres tend to form chain-like aggregates and percolated networks with increasing dipolar coupling strength. We find that strong active forces override dipolar attractions, effectively inhibiting chain-like aggregation and network formation. Conversely, activating particles with low to moderate forces results in a fluid composed of active chains and rings. At strong dipolar coupling strengths, this active fluid transitions into an active gel, consisting of a percolated network of active chains. Although the overall structure of the active gel remains interconnected, the network experiences more frequent configurational rearrangements due to the reduced bond lifetime of active dipolar particles. Consequently, particles exhibit enhanced translational and rotational diffusion within the active fluid of strings and active gels compared to their passive counterparts. We quantify the influence of activity on aggregate topology as they transition from branched structures to unconnected chains and rings. Our findings are summarized in a state diagram, delineating the impact of dipolar coupling strength and active force magnitude on the system.
Diagnosing up-scattered deuterium–tritium fusion neutrons produced in burning plasmas at the National Ignition Facility (invited)
Authors: Jeet J. , Appelbe B. D. , Crilly A. J. , Divol L. , Eckart M. , Hahn K. D. , Hartouni E. P. , Hayes A. , Kerr S. , Kim Y. , Mariscal E. , Moore A. S. , Ramirez A. , Rusev G. , Schlossberg D. J.
Published: September 2024

In the push to higher performance fusion plasmas, two critical quantities to diagnose are α-heat deposition that can improve and impurities mixed into the plasma that can limit performance. In high-density, highly collisional inertial confinement fusion burning plasmas, there is a significant probability that deuterium–tritium (DT) fusion products, 14.1 MeV neutrons and 3.5 MeV α-particles, will collide with and deposit energy onto (“up-scatter”) surrounding deuterium and tritium fuel ions. These up-scattered D and T ions can then undergo fusion while in-flight and produce an up-scattered neutron (15–30 MeV). These reaction-in-flight (RIF) neutrons can then be uniquely identified in the measured neutron energy spectrum. The magnitude, shape, and relative size of this spectral feature can inform models of stopping-power in the DT plasma and hence is directly proportional to α-heat deposition. In addition, the RIF spectrum can be related to mix into the burning fuel, particularly relevant for high-Z shell and other emerging National Ignition Facility platforms. The neutron time-of-flight diagnostic upgrades needed to obtain this small signal, ∼10−5 times the primary DT neutron peak, will be discussed. Results from several gain > 1 implosions will be shown and compared to previous RIF spectra. Finally, comparisons of experimental data to a simplified computational model will be made.
Quantitative determination of twist angle and strain in Van der Waals moiré superlattices
Authors: Tran Steven J. , Uslu Jan-Lucas , Pendharkar Mihir , Finney Joe , Sharpe Aaron L. , Hocking Marisa , Bittner Nathan J. , Watanabe Kenji , Taniguchi Takashi , Kastner Marc A. , Mannix Andrew J. , Goldhaber-Gordon David
Published: September 2024

Scanning probe techniques are popular, nondestructive ways to visualize the real space structure of Van der Waals moirés. The high lateral spatial resolution provided by these techniques enables extracting the moiré lattice vectors from a scanning probe image. We have found that the extracted values, while precise, are not necessarily accurate. Scan-to-scan variations in the behavior of the piezos that drive the scanning probe and thermally driven slow relative drift between probe and sample produce systematic errors in the extraction of lattice vectors. In this Letter, we identify the errors and provide a protocol to correct for them. Applying this protocol to an ensemble of ten successive scans of near-magic-angle twisted bilayer graphene, we are able to reduce our errors in extracting lattice vectors to less than 1%. This translates to extracting twist angles with a statistical uncertainty less than 0.001° and uniaxial heterostrain with uncertainty on the order of 0.002%.
An algorithm for simplified recurrence analysis
Authors: Delage Rémi , Nakata Toshihiko
Published: September 2024

Recurrence analysis applications are hindered by several issues including the selection of critical parameters, noise sensitivity, computational complexity, or the analysis of non-stationary systems. Great progresses have been made by the community to address these issues individually, yet the diversity of resulting techniques with often additional parameters as well as a lack of consensus still impedes its use by nonspecialists. We present a procedure for simplified recurrence analysis based on compact recurrence plots with automatized parameter selection and enhanced noise robustness, and that are suited to the analysis of complex non-stationary systems. This approach aims at supporting the expansion of recurrence analysis for currently challenging or future applications such as for large systems, on-site studies, or using machine learning. The method is demonstrated on both synthetic and real data showing promising results.
Non-equilibrium rate theory for polariton relaxation dynamics
Authors: Lai Yifan , Ying Wenxiang , Huo Pengfei
Published: September 2024

We derive an analytic expression of the non-equilibrium Fermi’s golden rule (NE-FGR) expression for a Holstein–Tavis–Cumming Hamiltonian, a universal model for many molecules collectively coupled to the optical cavity. These NE-FGR expressions capture the full-time-dependent behavior of the rate constant for transitions from polariton states to dark states. The rate is shown to be reduced to the well-known frequency domain-based equilibrium Fermi’s golden rule (E-FGR) expression in the equilibrium and collective limit and is shown to retain the same scaling with the number of sites in non-equilibrium and non-collective cases. We use these NE-FGR to perform population dynamics with a time-non-local and time-local quantum master equation and obtain accurate population dynamics from the initially occupied upper or lower polariton states. Furthermore, NE-FGR significantly improves the accuracy of the population dynamics when starting from the lower polariton compared to the E-FGR theory, highlighting the importance of the non-Markovian behavior and the short-time transient behavior in the transition rate constant.
Expanding on the plecstatin anticancer agent class: exchange of the chlorido ligand for N-heterocyclic ligands
Authors: Kumar Saawan , Riisom Mie , Jamieson Stephen M. F. , Söhnel Tilo , Bhargava Suresh , Sun Jing , Hartinger Christian G.
Published: September 2024

Metal piano-stool complexes based on pyridinecarbothioamide (PCA) have shown promising antiproliferative and in vivo anticancer activity, in particular [Ru(cym)(p-F-PCA)Cl]PF6 (cym is η6-p-cymene; plecstatin-1). The impact of modifications of the PCA and π-bound ligands on biological properties has been extensively investigated. Herein, we explored the influence of exchanging the chlorido ligand with the N-heterocycles 1-methylimidazole, 1-methylbenzimidazole and pyridine. In solution, an equilibrium between the protonated and deprotonated forms of the thioamide bond was observed, which was found dictated by the solvent system with both species detected in polar solvents. [Ru(cym)(PCA)Cl]+ complexes exhibit unique behaviour in an aqueous environment where they rapidly form dimeric species after substitution of the chlorido ligand for the sulfur donor of the PCA ligand of a second complex molecule. This was also observed for the synthesised complexes with the N-heterocyclic ligands being cleaved from the Ru centre allowing for dimerisation, which may be reversed by acidification of the solution resulting in the formation of equivalent mononuclear compounds. This behaviour explains the similar biological properties of the complexes with respect to that of plecstatin-1.
Photolysis characteristics and influencing factors of the pesticide pyrimethanil in natural waters
Authors: Zhao Jiayun , Liu Hui , Li Zhiwen , Zhu Xiaomei , Sun Bing
Published: September 2024

Environmental context The widespread use of pesticides leads to a large amount of residues in the natural water where photochemical degradation is the main removal process. The influencing factors on the photodegradation of pyrimethanil were investigated in different aqueous matrix, and the chlorinated product was found in saline water, indicating a higher ecologic risk of residual pyrimethanil in estuarine and nearshore water than in fresh water. A better understanding of the natural degradation mechanisms for pesticides will inform their safer use in agriculture. Rationale The photodegradation behaviour of pesticides in natural environments significantly affects their ecological safety. Pyrimethanil (PYR) is a widely used fungicide and is classified as a possible human carcinogen. The influencing factors for the photodegradation of PYR in different aqueous matrixes were studied, and the degradation pathway was evaluated. Methodology The photodegradation behaviour of PYR was investigated in fresh water and seawater, and the effects of the main photosensitive components including dissolved organic matter (DOM), chloride, Fe3+, NO3− and HCO3− were evaluated in aqueous solutions, and the degradation products determined by gas chromatography–mass spectrometry (GC-MS). Results The photolysis of PYR was much faster in fresh water than in seawater, where DOM and chloride played a role. As DOM model substances, humic acid (HA) and Suwannee River natural organic matter (SRNOM) both promoted PYR degradation, whereas chloride inhibited PYR’s degradation in the presence of SRNOM and resulted in a chlorinated byproduct. Ferric, nitrate and bicarbonate ions promoted PYR degradation. Discussion PYR is a refractory pesticide for photodegradation, especially in saline water environments where a chlorinated product was formed. The result indicates a high ecological risk of residual PYR in estuarine and nearshore water.
Habitat use strategies of African elephants under different seasonal and ecological constraints
Authors: Chui Scott Y. S. , Getz Wayne M. , Henley Michelle , Seidel Dana P. , Keith Mark , Parrini Francesca , Karczmarski Leszek
Published: September 2024

Context Habitat selection is a fundamental process that shapes animal spatial ecology. Species with wide geographic distribution that occupy diverse habitats have to adapt their resource acquisition strategies to maximise their effectiveness under local ecological constraints, leading to intraspecific behavioural variability. Identifying environmental determinants of habitat use pattern and regional intraspecific differences advances our understanding of the ecological underpinnings of animal behaviour and is important in strategising effective conservation and management of free-ranging populations. Aims The aim of this study was to assess individual heterogeneity of habitat selection and use by African elephants under different seasonal and ecological constraints, in order to better understand the processes underlying their spatial behaviour. Methods We investigated the habitat selection pattern of 19 African elephants equipped with satellite-linked GPS-collars in two different ecosystems, resource-rich bushveld bordering Kruger National Park, South Africa (six individuals) and arid savannah of Etosha National Park, Namibia (13 individuals). By constructing individual-specific and population-level resource selection functions (RSFs), we examined seasonal differences of elephant habitat use pattern to identify the underlying ecological mechanisms. Key results Elephants were attracted to surface water in both study areas; but when water availability decreased in arid environment, they showed individual-specific preference in using natural vs artificial water sources. Road networks enabled efficient travel among resource patches, but its use differed between individuals. Areas with higher and more predictable vegetation productivity were generally preferred by elephants in dry season, but in more competitive arid savannah system there were individual/group-specific seasonal differences in resource selection patterns, likely reflecting the social dynamics among individuals. At population-level, the habitat selection pattern was less apparent due to considerable intra-population variability. Conclusions The substantial differences in model coefficients within and between our study populations demonstrate the spatio-behavioural plasticity of elephants under various environmental conditions and suggest that population-level RSFs may over-simplify elephants’ socio-ecological complexity. Implications Within the resource competition paradigm, individual-specific habitat selection may be as essential in maintaining population resilience as is the population-level pattern of resource use. Consequently, spatio-behavioural heterogeneity within and between populations should be accounted for in resource selection studies and all subsequent conservation management policies.
Romania’s first female prime minister’s meme-ification
Authors: Negrea-Busuioc Elena , Ștefăniță Oana , Buf Diana-Maria
Published: September 2024

Political memes are ubiquitous in social media. They are easy to make, alter and spread, and they are a funny way
of sanctioning politicians. This paper seeks to analyze the satirical memes targeting Viorica Dăncilă and to explore the extent to
which such memes could be considered a manifestation of political trivialization rather than of criticism. Drawing on qualitative
methods of text and image analysis we ask: (1) how is humor constructed in political memes targeting Romania’s former prime
minister, and (2) to what extent could the memes be considered either a form of political criticism or a matter of pure
entertainment. Our findings show that the humor in the examined memes is largely offensive (including sexist and misogynistic),
sometimes at the expense of humor display. We argue that such offensive content triggers a cancellation of the criticizing force
of the memes and an amplification of their short-lived amusement value.
Limits, frontiers, antagonism
Authors: De Toffoli Matteo
Published: September 2024

The paper deals with the role of antagonism within post-structuralist discourse theory, and does so by revisiting
the genesis and transformations of the conceptual couple limit/frontier. The first paragraphs introduce the conception of
discourse put forward by Ernesto Laclau and Chantal Mouffe, and explain why they envisaged the necessity of discursive closure in
antagonistic terms. The central sections deal with the emergence of the concept of antagonism in Hegemony and Socialist
Strategy (1985) and its connection with the notions of limit and frontier, highlight the theoretical problems arising
thereof and follow the refinements advanced by discourse-theoretical critics and scholars. The last paragraph draws the
consequences of this debate and argues for a rehabilitation of the concept of antagonism: not to be intended as a fate inherent to
the constitution of any discourse, but as a useful political tool for questioning concrete discursive formations.
Attention allocation in (L1) subtitled and (L2) captioned video
viewing
Authors: Pujadas Geòrgia , Puimège Eva
Published: September 2024

Pre-directing learners’ attention to novel words
facilitates learning through meaning-focused input, but little is known
about the effect that vocabulary-focused activities may have on video
processing and comprehension. This study investigates attention allocation
in (L1) subtitled and (L2) captioned video viewing and explores potential
trade-offs between pre-viewing instruction and comprehension. Eighty-seven
Catalan/Spanish L2-English beginner learners watched an eight-minute video
with either captions or subtitles while their eye-movements were recorded.
Half of the participants in each language condition were pre-taught
vocabulary. Results showed that pre-viewing instruction affected attention
allocation only in the captions group, with participants tending to spend
less time on target captions and comprehension-relevant captions. Allocating
attention to vocabulary, however, did not seem to hinder comprehension in a
significant manner.
Vocabulary learning from audiovisual input at first exposure in young
adult novice learners
Authors: Miralpeix Imma , Gesa Ferran , Suárez Maria del Mar
Published: September 2024

In this ‘First Exposure’ (FE) study, 106
Catalan/Spanish young adults proficient in English watched a short advert
with the audio in English and subtitles in Polish, a language they were not
familiar with. Results indicated that vocabulary learning took
place, as their meaning
recognition scores were significantly higher than those of a
control group who had not seen the video. The most recurrent learning
strategies these novice
learners used were associations with imagery and with
vocabulary in previously learned languages, along with attention to specific
input factors such as frequency of word occurrence. Findings reveal how
audiovisual input can help vocabulary acquisition at FE, as well as factors
relevant for learning from video viewing at these very first stages.