bluuebunny/crossref_metadata_2025 huggingface dataset:
Supramolecularly modulated carbon-centered radicals: toward selective oxidation from benzyl alcohol to aldehyde
Authors: Tang Xingchen , Mei Shan , Xu Jiang-Fei , Zhang Xi
Published: April 2024

Host–guest interaction of cucurbit[7]uril is used to adjust the reactivity of ketyl radicals and benzoyl radicals, therefore enhancing the aldehyde selectivity of photo-induced oxidation of benzyl alcohol.
Layered rare-earth hydroxides as multi-modal medical imaging probes: particle size optimisation and compositional exploration
Authors: Strimaite Margarita , Wells Connor J. R. , Prior Timothy J. , Stuckey Daniel J. , Wells Jack A. , Davies Gemma-Louise , Williams Gareth R.
Published: April 2024

A detailed study into the synthesis and functional properties of layered rare-earth hydroxides (LRHs) is reported. It is possible to obtain precise control of particle size, and combining Tb and Gd in the LRH allows multi-modal imaging.
An innovative synthesis of carbon-coated TiO2 nanoparticles as a host for Na+ intercalation in sodium-ion batteries
Authors: Soudant Tanguy , Fleutot Solenne , Bruyère Stéphanie , Speyer Lucie , Hupont Sébastien , Bolmont Mickaël , Girardet Thomas , Raspado Loris , Hérold Claire , Cahen Sébastien
Published: April 2024

A unique titanium–carbon precursor synthesized using a microwave route and heat treatment to integrate TiO2 nanoparticles into carbon for sodium-ion battery anodes.
Organometallics in molecular junctions: conductance, functions, and reactions
Authors: Tanaka Yuya
Published: April 2024

This review summarizes recent progress in organometallic molecular junctions.
A bi-functional air electrode developed from a dual-MOF strategy for high-performance zinc–air batteries
Authors: Arafat Yasir , Azhar Muhammad Rizwan , Zhong Yijun , Xu Xiaomin , Tadé Moses O. , Shao Zongping
Published: April 2024

We designed a bi-functional (OER/ORR) air electrode using the a dual-MOF strategy for ZABs wherein a Fe-containing MOF (MIL-100) acts as a support to expose OER active sites and carbonized ZIF-67 acts as the ORR catalyst.
Electric field-induced phosphorization to prepare CoP@Biochar composites for efficient bifunctional oxygen electrocatalysis
Authors: Wu Xianli , Zhou Ting , Teng Teng , Liu Shuling , Lu Bangan , Mehdi Sehrish , Liu Yanyan , Jiang Jianchun , Wang Yongfeng , Li Baojun
Published: April 2024

An electric field-induction method was employed to construct an oxygen electrocatalyst (CoP@NWC). CoP@NWC exhibits excellent ORR/OER bifunctional catalytic activity (ΔE = 0.65 V) because of the multi-active site integration strategy.
Effect of ammonia addition on the dispersion and activity of supported copper species on porous silica–alumina hollow spheres for catalytic decomposition of nitrous oxide
Authors: Umegaki Tetsuo , Nakamura Takeru , Kojima Yoshiyuki
Published: April 2024

In this work, we investigated the influence of ammonia addition in the immersion process of active species on the dispersion and activity of copper-supported porous hollow silica–alumina sphere catalysts for the decomposition of nitrous oxide.
Halide exchange mediated cation exchange facilitates room temperature co-doping of d-and f-block elements in cesium lead halide perovskite nanoparticles
Authors: Philip Jomy Jose , Debnath Gouranga H. , Waldeck David H. , Balakrishna R. Geetha
Published: April 2024

A facile halide and cation exchange reaction to co-dope d- and f-block elements in cesium lead halide nanoparticles at room temperature.
Synthesis of deuteriodifluoromethylthiolated isocoumarins-1-imines and isocoumarins enabled by multi-component reagents system (MCRS)
Authors: Li Xuemin , Shi Haofeng , He Jiaxin , Wu Jialiang , Sun Fengxia , Du Yunfei
Published: April 2024

The combining use of BnSCF2D, mCPBA and Tf2O serves as an efficient multi-component reagents system (MCRS) for the synthesis of 4-SCF2D-isocoumarins-1-imines/isocoumarins via intramolecular cyclization of 2-alkynylbenzamides/2-alkynylbenzoates.
A high-resolution structural characterization and physicochemical study of how a peptoid binds to an oncoprotein MDM2
Authors: Yokomine Marin , Morimoto Jumpei , Fukuda Yasuhiro , Ueda Takumi , Takeuchi Koh , Umezawa Koji , Ago Hideo , Matsuura Hiroaki , Ueno Go , Senoo Akinobu , Nagatoishi Satoru , Tsumoto Kouhei , Sando Shinsuke
Published: April 2024

How a peptoid binds to a protein was revealed by a co-crystal structure and systematic physicochemical studies.
Recent advances in CO2 hydrogenation to methane using single-atom catalysts
Authors: Choudhary Neha , Nabeela Kallayi , Mate Nirmiti , Mobin Shaikh M.
Published: April 2024

Catalytic reduction of CO2 to methane conversion by single-atom catalysts (SACs).
Sulfate: a neglected (but potentially highly relevant) anion
Authors: den Bakker Emil , Smith Desiree E.C. , Finken Martijn J.J. , Wamelink Mirjam M.C. , Salomons Gajja S. , van de Kamp Jiddeke M. , Bökenkamp Arend
Published: April 2024

Sulfate is an important anion as sulfonation is essential in modulation of several compounds, such as exogens, polysaccharide chains of proteoglycans, cholesterol or cholesterol derivatives and tyrosine residues of several proteins. Sulfonation requires the presence of both the sulfate donor 3′-phosphoadenosine-5′-phosphosulfate (PAPS) and a sulfotransferase. Genetic disorders affecting sulfonation, associated with skeletal abnormalities, impaired neurological development and endocrinopathies, demonstrate the importance of sulfate. Yet sulfate is not measured in clinical practice. This review addresses sulfate metabolism and consequences of sulfonation defects, how to measure sulfate and why we should measure sulfate more often.
Optimizing secure power allocation in massive MIMO systems with an eavesdropper under imperfect CSI conditions
Authors: Gharagezlou Abdolrasoul Sakhaei , Nangir Mahdi , Imani Nima
Published: April 2024

This paper discusses the operation of a massive multiple‐input multiple‐output (MIMO) system from a different perspective. The system is performed in the presence of an eavesdropper who is trying to disrupt the message being transmitted between the base station (BS) and the users. An attempt has been made to maximize the secure energy efficiency (EE) of the system by allocating appropriate power to each user. The channel state information (CSI) between users and the BS is considered imperfect and the employed precoding scheme is the zero forcing (ZF). The CSI related to the eavesdropper is considered to be perfect and its precoding is assumed to be the maximum ratio transmission (MRT). The problem of optimization that is for maximizing the EE has two constraints including the maximum transmission power and the minimum user data rate. To improve the performance of system, the cell division technique is applied, which results in approaching the performance of system to the without eavesdropper scenario. Five various scenarios have been investigated in this research, and it is proved that the proposed method improves the system performance in all cases. The numerical and simulation results obtained from implementation of the proposed algorithm confirm the claim.
Evaluating transient behaviour of large‐scale photovoltaic systems during lightning events using enhanced finite difference time domain method with variable cell size approach
Authors: Hetita Ibrahim , Mansour Diaa‐Eldin A. , Han Yang , Yang Ping , Wang Congling , Darwish Mohamed M. F. , Lehtonen Matti , Zalhaf Amr S.
Published: April 2024

Photovoltaic (PV) arrays are usually installed in open areas; hence, they are vulnerable to lightning strikes that can result in cell degradation, complete damage, service disruption, and increased maintenance costs. As a result, it is imperative to develop an effective and efficient lightning protection system by evaluating the transient behaviour of PV arrays during lightning events. The aim is to evaluate the transient analysis of large‐scale PV systems when subjected to lightning strikes using the finite difference time domain (FDTD) technique. Transient overvoltages are calculated at various points within the mounting system. To optimise the FDTD method's execution time and make it more suitable for less powerful hardware, a variable cell size approach is employed. Specifically, larger cell dimensions are used in the earthing system and smaller cell dimensions are used in the mounting system. The FDTD method is utilised to calculate the temporal variation of transient overvoltages for large‐scale PV systems under different scenarios, including variations in the striking point, soil resistivity, and the presence of a metal frame. Simulation results indicate that the highest transient overvoltages occur at the striking point, and these values increase with the presence of a PV metal frame as well as with higher soil resistivity. Furthermore, a comparison is performed between the overvoltage results obtained from the FDTD approach and the partial element equivalent circuit (PEEC) method at the four corner points of the mounting systems to demonstrate the superior accuracy of the FDTD method. Besides, a laboratory experiment is conducted on a small‐scale PV system to validate the simulation results. The calculated overvoltages obtained from the FDTD and PEEC methods are compared with the measured values, yielding a mean absolute error of 5% and 11% for the FDTD and PEEC methods, respectively, thereby confirming the accuracy of the FDTD simulation model.
A MUSE view of the core of the giant low-surface-brightness galaxy Malin 1
Authors: Johnston Evelyn J. , Galaz Gaspar , Blaña Matias , Amram Philippe , Boissier Samuel , Eigenthaler Paul , Epinat Benoît , Junais  , Ordenes-Briceño Yasna , Puzia Thomas , Weilbacher Peter M.
Published: April 2024

Aims. The central region of the giant low-surface-brightness galaxy Malin 1 has long been known to have a complex morphology, with evidence of a bulge, disc, and potentially a bar hosting asymmetric star formation. In this work, we use VLT/MUSE data to resolve the central region of Malin 1 in order to determine its structure.

Methods. We used careful light profile fitting in every image slice of the datacube to create wavelength-dependent models of each morphological component, from which we were able to cleanly extract their spectra. We then used the kinematics and emission line properties from these spectra to better understand the nature of each component extracted from our model fitting.

Results. We report the detection of a pair of distinct sources at the centre of this galaxy with a separation of ∼1.05″, which corresponds to a separation on sky of ∼1.9 kpc. The radial velocity data of each object confirm that they both lie in the kinematic core of the galaxy. An analysis of the emission lines reveals that the central compact source is more consistent with being ionised through star formation and/or a LINER, while the off-centre compact source lies closer to the separation between star-forming galaxies and active galactic nuclei.

Conclusions. This evidence suggests that the centre of Malin 1 hosts either a bar with asymmetric star formation or two distinct components. In the latter scenario, we propose two hypotheses for the nature of the off-centre compact source-it could either be a star-forming clump, containing one or more star clusters, that is in the process of falling into the core of the galaxy and eventually merging with the central nuclear star cluster, or it could be a clump of gas falling into the centre of the galaxy from either outside or from the disc and triggering star formation there.
Comparing the three-dimensional morphological asymmetries in the ejecta of Kepler and Tycho in X-rays
Authors: Picquenot A. , Holland-Ashford T. , Williams B. J.
Published: April 2024

Aims. Recent simulations have shown that asymmetries in the ejecta distribution of supernova remnants (SNRs) may be a reflection of asymmetries left over from the initial supernova explosion. Thus, SNR studies provide a vital means for testing and constraining model predictions in relation to the distribution of heavy elements, which are key to improving our understanding of the explosion mechanisms in Type Ia supernovae.

Methods. The use of a novel blind source separation method applied to the megasecond X-ray observations of the historic Kepler and Tycho supernova remnants has revealed maps of the ejecta distribution. These maps are endowed with an unprecedented level of detail and clear separations from the continuum emission. Our method also provides a three-dimensional (3D) view of the ejecta by individually disentangling red- and blueshifted spectral components associated with images of the Si, S, Ar, Ca, and Fe emission. This approach provides insights into the morphology of the ejecta distribution in those two remnants.

Results. Those mappings have allowed us to thoroughly investigate the asymmetries in the intermediate-mass elements and Fe distribution in two Type Ia supernova remnants. We also compared the results with the core-collapse Cassiopeia A remnant, which we had studied previously. The images obtained confirm, as expected for Type Ia SNRs, that the Fe distribution is mostly closer to the core than that of intermediate-mass elements. They also highlight peculiar features in the ejecta distribution, such as the Fe-rich southeastern knot in Tycho.
Abundances in eight bulge stars from the optical and near-infrared
Authors: da Silva Patrícia , Barbuy B. , Ernandes H. , Souza S. O. , Fernández-Trincado J. G. , González-Díaz D.
Published: April 2024

Context. The abundances of the α-elements are key for understanding the early chemical enrichment of the Galactic bulge. The elements of interest present lines in different wavelength regions, and some of them show lines only in part of the spectra. In the present work, the CNO trio, the a-elements Mg, Si, Ca, and Ti, and odd-Z Na and Al are examined as measured from optical and H-band lines.

Aims. The aim of this work is to carry out a detailed comparison of stellar parameters and abundances derived in the optical and near-infrared (H-band). We also inspect the best available lines for a list of bulge stars previously analyzed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) team in the H-band and by our group in the optical. This work is mainly of interest to spectroscopists.

Methods. In the present work, we compared the stellar parameters and abundance results derived from APOGEE H-band spectra with optical analyses based on Ultraviolet and Visual Echelle Spectrograph at the Very Large Telescope (VLT/UVES) data for eight bulge stars.

Results. We point out the most suitable wavelength region for each of the studied elements, and highlight difficulties in the derivation of stellar parameters both in the optical and H-band. The near-infrared will allow observations of a large number of stars in the near future given new instruments soon to be available. The identification of spectral lines in this spectral region and the investigation of their reliability are ongoing efforts worldwide. New instruments will also allow simultaneous observation of H-band and optical.
The formation of the magnetic symbiotic star FN Sgr
Authors: Belloni Diogo , Mikołajewska Joanna , Schreiber Matthias R.
Published: April 2024

Context. There are several symbiotic stars (e.g., BF Cyg, Z And, and FN Sgr) in which periodic signals of tens of minutes have been detected. These periods have been interpreted as the spin period of magnetic white dwarfs that accrete through a magnetic stream originating from a truncated accretion disc.

Aims. To shed light on the origin of magnetic symbiotic stars, we investigated the system FN Sgr in detail. We searched for a reasonable formation pathway to explain its stellar and binary parameters including the magnetic field of the accreting white dwarf.

Methods. We used the MESA code to carry out pre-CE and post-CE binary evolution and determined the outcome of CE evolution assuming the energy formalism. For the origin and evolution of the white dwarf magnetic field, we adopted the crystallization scenario.

Results. We found that FN Sgr can be explained as follows. First, a non-magnetic white dwarf is formed through CE evolution. Later, during post-CE evolution, the white dwarf starts to crystallize and a weak magnetic field is generated. After a few hundred million years, the magnetic field penetrates the white dwarf surface and becomes detectable. Meanwhile, its companion evolves and becomes an evolved red giant. Subsequently, the white dwarf accretes part of the angular momentum from the red giant stellar winds. As a result, the white dwarf spin period decreases and its magnetic field reaches super-equipartition, getting amplified due to a rotation- and crystallization-driven dynamo. The binary then evolves into a symbiotic star, with a magnetic white dwarf accreting from an evolved red giant through atmospheric Roche-lobe overflow.

Conclusions. We conclude that the rotation- and crystallization-driven dynamo scenario, or any age-dependent scenario, can explain the origin of magnetic symbiotic stars reasonably well. This adds another piece to the pile of evidence supporting this scenario. If our formation channel is correct, our findings suggest that white dwarfs in most symbiotic stars formed through CE evolution might be magnetic, provided that the red giant has spent ≳3 Gyr as a main-sequence star.
Erniedrigte eGFR und Albuminurie erhöhen Risiko für 10 unerwünschte klinische Ereignisse
Authors: Brandenburg Vincent
Published: April 2024

Diese Publikation beschäftigt sich mit dem zwar prinzipiell gut bekannten, aber in seiner gesamten Dimension wohl immer noch unterschätzten Thema der Risikosteigerung für zukünftige unerwünschte klinische Ereignisse durch eine chronische Nierenerkrankung (als eingeschränkte glomeruläre Filtrationsrate (eGFR)) und eine erhöhte Albuminurie). Die vorliegende Analyse liefert hierzu das bisher umfangreichste Datenmaterial.
Hypertonietherapie bei Nierenerkrankungen
Authors: Boger Leonard , Saritas Turgay
Published: April 2024

Die arterielle Hypertonie bei Patienten mit einer chronischen Nierenerkrankung (CKD: „chronic kidney disease“) ist häufig schlecht kontrolliert und der wichtigste modifizierbare Risikofaktor, der zur Progression der CKD beiträgt. Dieser Beitrag gibt einen Überblick über die aktuelle Diagnostik und Therapie der arteriellen Hypertonie in den verschiedenen CKD-Stadien, inklusive für Patienten mit Nierenersatztherapie und für Patienten nach einer Nierentransplantation. Die Diagnose und die Therapieüberwachung der Blutdruckwerte sollte bei allen CKD-Stadien ohne Nierenersatztherapie und bei Nierentransplantation primär mittels ambulanter Blutdruckmessung (ABDM) erfolgen. Bei allen CKD-Patienten empfiehlt die europäische Hypertonie-Leitlinie aus dem Jahr 2023 einen Zielblutdruck von < 140/90 mmHg (Praxisblutdruck) anzustreben. Insbesondere bei jüngeren Patienten mit Albuminurie und/oder Diabetes erscheint ein Blutdruckziel von < 130/80 mmHg vorteilhaft. In den CKD-Stadien 1–3 werden in erster Linie ACE-Inhibitoren (ACE: „angiotensin converting enzyme“) beziehungsweise Angiotensin-II-Rezeptor-Blocker (ACEi/ARB), Dihydropyridin-Kalzium-Antagonisten (CCB: „calcium channel blocker“) und Thiaziddiuretika eingesetzt. Als Reservemedikament ist Spironolacton zu bevorzugen. Die renale Denervation rückt als zusätzliche antihypertensive Option zunehmend in den Vordergrund. Die Gabe und das Erreichen der Maximaldosis von ACEi/ARB und MRA kann in fortgeschrittenen CKD-Stadien durch kaliumsenkende Ionenaustauscher ermöglicht werden. Bei hochgradig reduzierter Nierenfunktion (CKD-Stadien 4 und 5 ohne Nierensatztherapie) ist statt einem Thiaziddiuretikum der Einsatz eines Schleifendiuretikums ratsam. Bei Patienten mit Nierenersatztherapie sind Grundpfeiler der Therapie das Erreichen des Trockengewichts, eine effektive Dialysedosis und eine Kochsalzrestriktion. Medikamentös sind, im Gegensatz zu anderen CKD-Subgruppen, Betablocker und Kalziumantagonisten bevorzugte Medikamente. Patienten nach einer Nierentransplantation haben aufgrund vaskulärer Vorerkrankungen und unter Glukokortikoiden und Calcineurininhibitoren häufig einen schlecht kontrollierten Blutdruck. Kalziumantagonisten sind als Erstlinientherapie bei Hypertonie nach einer Nierentransplantation in Bezug auf die Blutdrucksenkung und das Transplantatüberleben wirksam.
Die Betreuung im Geburtszeitraum – eine Herausforderung an Geduld,
Sorgfalt und Kompetenz
Authors: Hildebrandt Sven
Published: April 2024

Der errechnete Geburtstermin markiert einen Tag, bis zu dem statistisch
betrachtet nur knapp die Hälfte aller Kinder tatsächlich geboren wurden. Dennoch
wird er häufig als eine Art „Ablaufdatum“ einer Schwangerschaft gesehen, mit
dessen Überschreiten sie pathologisch wird – zu Unrecht. Ein möglicherweise
falsch errechnetes Schwangerschaftsalter sowie individuelle Faktoren bei Mutter
und Kind können diesen Zeitpunkt verschieben. Daher ist es treffender, von einem
Geburtszeitraum zu sprechen. Dieser Leitfaden gibt Hebammen eine
Handlungsanleitung für die Betreuung vor und während des Geburtszeitraums.
Rizinusöl – vom alten Hausmittel zu aktueller
Forschung
Authors: Hünig Johanna
Published: April 2024

Dem seit der Antike zur Geburtseinleitung angewandten Rizinusöl hafteten lange
verschiedene Mythen an. Es galt als Hausmittel – ohne jegliche Evidenzen. Die in
den vergangenen Jahren vermehrt durchgeführten klinischen Studien zeigen
vielversprechende Ergebnisse auf, die eine weitere Forschung an Rizinusöl zur
Geburtseinleitung nahelegen.
American Society for Gastrointestinal Endoscopy–European Society of Gastrointestinal Endoscopy guideline on primary endoscopic bariatric and metabolic therapies for adults with obesity
Authors: Jirapinyo Pichamol , Hadefi Alia , Huberty Vincent , Sullivan Shelby , Thompson Christopher C. , Patai Árpád V. , Pannala Rahul , Goelder Stefan K. , Kushnir Vladimir , Barthet Marc , Apovian Caroline M. , Boskoski Ivo , Chapman Christopher G. , Davidson Paul , Donatelli Gianfranco , Kumbhari Vivek , Hayee Bu , Esker Janelle , Hucl Tomas , Pryor Aurora D. , Maselli Roberta , Schulman Allison R. , Pattou Francois , Zelber-Sagi Shira , Bain Paul A. , Durieux Valérie , Triantafyllou Konstantinos , Thosani Nirav
Published: April 2024

This joint ASGE-ESGE guideline provides an evidence-based summary and recommendations regarding the role of endoscopic bariatric and metabolic therapies (EBMTs) in the management of obesity. The document was developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework. It evaluates the efficacy and safety of EBMT devices and procedures that currently have CE mark or FDA-clearance/approval, or that had been approved within five years of document development. The guideline suggests the use of EBMTs plus lifestyle modification in patients with a BMI of ≥30 kg/m2, or with a BMI of 27.0–29.9 kg/m2 with at least 1 obesity-related comorbidity. Furthermore, it suggests the utilization of intragastric balloons and devices for endoscopic gastric remodeling (EGR) in conjunction with lifestyle modification for this patient population.
Temporal Analysis in Outcomes of Long-Term Mechanical Circulatory Support: Retrospective Study
Authors: Ondrusek Matej , Artemiou Panagiotis , Bezak Branislav , Gasparovic Ivo , By Theo MMH de , Durdik Stefan , Lesny Peter , Goncalvesova Eva , Hulman Michal
Published: April 2024

Background Mechanical assist device indications have changed in recent years. Reduced incidence of complications, better survival, and the third generation of mechanical support devices contributed to this change. In this single-center study, we focused on two time periods that are characterized by the use of different types of mechanical support devices, different patient characteristics, and change in the indications.

Methods The data were processed from the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). We retrospectively defined two time intervals to reflect changes in ventricular assist device technology (period 1: 2007–2015; period 2: 2016–20222). A total of 181 patients underwent left ventricular assist device implantation. Device utilization was the following: HeartMate II = 52 (76.4%) and HeartWare = 16 (23.6%) in period 1 and HeartMate II = 2 (1.8%), HeartMate 3 = 70 (61:9%), HeartWare = 29 (25.7%), SynCardia TAH = 10 (8.8%), and BerlinHeart EXCOR = 2 (1.8%) in period 2. The outcomes of the time intervals were analyzed and evaluated.

Results Survival was significantly higher during the second time period. Multivariate analysis revealed that age and bypass pump time are independent predictors of mortality. Idiopathic cardiomyopathy, bypass time, and the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) score are independent predictors of adverse events. Furthermore, the first period was noted to be at an increased risk of the following adverse events: pump thrombosis, gastrointestinal bleeding, and bleeding events.

Conclusion Despite the higher risk profile of the patients and persistent challenges, during the second period, there was a significant decrease in mortality and morbidity. The use of the HeartMate 3 device may have contributed to this result.
Ambient-space variational calculus for gauge fields on constant-curvature spacetimes
Authors: Bekaert Xavier , Boulanger Nicolas , Goncharov Yegor , Grigoriev Maxim
Published: April 2024

We propose a systematic generating procedure to construct free Lagrangians for massive, massless and partially massless, totally-symmetric tensor fields on AdSd+1 starting from the Becchi–Rouet–Stora–Tyutin (BRST) Lagrangian description of massless fields in the flat ambient space Rd,2. A novelty is that the Lagrangian is described by a d + 1 form on Rd,2 whose pullback to AdSd+1 gives the genuine Lagrangian defined on anti de Sitter spacetime. Our derivation uses the triplet formulation originating from the first-quantized BRST approach, where the action principle is determined by the BRST operator and the inner product of a first-quantised system. In this way we build, in a manifestly so(2, d)-covariant manner, a unifying action principle for the three types of fields mentioned above. In particular, our derivation justifies the form of some actions proposed earlier for massive and massless fields on (anti)-de Sitter. We also give a general setup for ambient Lagrangians in terms of the respective jet-bundles and variational bi-complexes. In particular we introduce a suitable ambient-space Euler–Lagrange differential which allows one to derive the equations of motion ambiently, i.e., without the need to explicitly derive the respective spacetime Lagrangian.
Experimental and modeling study of the impact of upstream D2 puff on divertor detachment and impurity control with argon seeding in EAST
Authors: He Tao , Yang Zhongshi , Li Kedong , Wang Liang , Jia Guozhang , Liu Xiaoju , Niu Guojian , Lin Xin , Nian Feifei , Wang Rong , Wu Kai , Yu Lin , Meng Lingyi , Liang Ruirong , Wang Minrui , Zhang Ling , Zhang Tao , Mao Songtao , Zang Qing , Ding Fang , Zhang Qing , Zhao Pingan , Luo Guang-Nan
Published: April 2024

Radiative divertor is an effective method for the divertor heat flux control, but excessive core impurity radiation can deteriorate the confinement in tokamaks. In recent EAST experiments, the compatibility of divertor detachment and impurity control with good core confinement (H98,y2 ∼1) has been achieved simultaneously by combining an upstream deuterium (D2) puff and divertor argon (Ar) seeding. Both experimental and SOLPS-ITER modeling reveal that additional D2 puff can further mitigate the target heat load and facilitate the detachment. The SOLPS-ITER results also show that the D2 puff makes a limited contribution to the Ar line radiation but a significant contribution to the neutral radiation in the SOL and divertor regions. The physical mechanism behind the effect of the D2 puff on the Ar retention is also revealed by the modeling. The increase in the Ar velocity is the major reason for the improved Ar retention in the partial detachment state. The increase in vAr is mainly caused by the strengthening of frictional drag of D+, which is because the additional D2 puff increases the pressure gradient force (FPG) and the electric field force (FE) on D+. Further analysis reveals that in the deep detachment state, some other negative effects play a dominant role in determining the Ar retention, such as the shift of the region of the Ar+ ionization source, the decrease in the strength of the Ar+ ionization source, and the net force on the Ar ions near the target.
Analysis of the new complementary unit Weibull model from adaptive progressively type-II hybrid
Authors: Alotaibi Refah , Nassar Mazen , Elshahhat Ahmed
Published: April 2024

In this study, we look at some estimation issues for complementary unit Weibull distributions in the context of adaptive progressive type-II hybrid censoring. The point and interval estimations of the model parameters, as well as a number of its reliability indices, are explored. The likelihood frequentist approach is used as a classical strategy to obtain the point and approximate confidence ranges. The median parameter of the distribution is produced in a closed form as a function of the shape parameter, while the shape parameter can be obtained iteratively. The squared error loss function and gamma and beta prior distributions are used for evaluating Bayes estimates. The Markov chain Monte Carlo method is used to solve the difficult posterior distribution expression in order to provide Bayes estimates and the highest posterior density credible ranges. A simulation study is done to evaluate the efficacy of various estimating methodologies making use of different circumstances for sample sizes and progressive censoring strategies. Finally, three real-world datasets from veterinary, industrial, and physical applications are examined to highlight the practical importance of the provided methodologies.
AlGaN/GaN bilateral IMPATT device by two-dimensional electron gas for terahertz application
Authors: Dai Yang , Li Yukun , Gao Leiyu , Zuo Jing , Zhang Biying , Chen Cheng , Wang Zhongxu , Zhao Wu
Published: April 2024

A novel bilateral impact-ionization-avalanche-transit-time (BIMPATT) diode based on AlGaN/GaN two-dimensional electron gas is proposed in this article. The BIMPATT is compatible with the available GaN high electron mobility transistor (HEMT) manufacturing process and has a shorter actual electron transit distance than existing HEMT-like IMPATT (HIMPATT) diodes. Compared with the same-sized HIMPATT, the optimum frequency of BIMPATT rises from 320 to 420 GHz and possesses a far wider operating frequency band, especially in the near 0.9 THz range. The maximum DC-RF conversion efficiency rises from 12.9% to 17.6%. The maximum RF power of BIMPATT is 3.18 W/mm, which is similar to 3.12 W/mm of the HIMPATT. Furthermore, our simulation demonstrated that the characteristics of BIMPATT are significantly affected by the length of anode and the thickness of the AlGaN barrier layer. The effects of ohmic contact resistance and background impurities on BIMPATT are also taken into account. This paper provides a reference for the design and characteristics enhancement of the lateral IMPATT devices.
Normalized solutions for Kirchhoff–Choquard type equations with different potentials
Authors: Liu Min , Sun Rui
Published: April 2024

In this paper, we are concerned with a Kirchhoff-Choquard type equation with L2-prescribed mass. Under different cases of the potential, we prove the existence of normalized ground state solutions to this equation. To obtain the boundedness from below of the energy functional and the compactness of the minimizing sequence, we apply the Gagliardo-Nirenberg inequality with the Riesz potential and the relationship between the different minimal energies corresponding to different mass. We also extend the results to the fractional Kirchhoff-Choquard type equation.
A review on charged-particle transport modeling for laser direct-drive fusion
Authors: Hu S. X. , Nichols K. A. , Shaffer N. R. , Arnold B. , White A. J. , Collins L. A. , Karasiev V. V. , Zhang S. , Goncharov V. N. , Shah R. C. , Mihaylov D. I. , Jiang S. , Ping Y.
Published: April 2024

Inertial confinement fusion (ICF) with the laser-indirect-drive scheme has recently made a tremendous breakthrough recently after decades of intensive research effort. Taking this success to the next step, the ICF community is coming to a general consensus that laser direct-drive (LDD) fusion might be the viable way for enabling inertial fusion energy (IFE) and high-gain targets for other applications. Designing and understanding LDD fusion targets heavily rely on radiation-hydrodynamic code simulations, in which charged-particle transport plays an essential role in modeling laser-target energy coupling and bootstrap heating of fusion-produced α-particles. To better simulate charged-particle transport in LDD targets, over the past four decades the plasma physics community has advanced transport calculations from simple plasma physics models to sophisticated computations based on first-principles methods. In this review, we give an overview of the current status of charged-particle transport modeling for LDD fusion, including what challenges we still face and the possible paths moving forward to advance transport modeling for ICF simulations. We hope this review will provide a summary of exciting challenges to stimulate young minds to enter the field, facilitate further progress in understanding warm-dense matter physics, and ultimately bridge toward the success of reliable LDD fusion designs for IFE and other high-gain ICF applications.
PigmentHunter: A point-and-click application for automated chlorophyll-protein simulations
Authors: Ahad S. , Lin C. , Reppert M.
Published: April 2024

Chlorophyll proteins (CPs) are the workhorses of biological photosynthesis, working together to absorb solar energy, transfer it to chemically active reaction centers, and control the charge-separation process that drives its storage as chemical energy. Yet predicting CP optical and electronic properties remains a serious challenge, driven by the computational difficulty of treating large, electronically coupled molecular pigments embedded in a dynamically structured protein environment. To address this challenge, we introduce here an analysis tool called PigmentHunter, which automates the process of preparing CP structures for molecular dynamics (MD), running short MD simulations on the nanoHUB.org science gateway, and then using electrostatic and steric analysis routines to predict optical absorption, fluorescence, and circular dichroism spectra within a Frenkel exciton model. Inter-pigment couplings are evaluated using point-dipole or transition-charge coupling models, while site energies can be estimated using both electrostatic and ring-deformation approaches. The package is built in a Jupyter Notebook environment, with a point-and-click interface that can be used either to manually prepare individual structures or to batch-process many structures at once. We illustrate PigmentHunter’s capabilities with example simulations on spectral line shapes in the light harvesting 2 complex, site energies in the Fenna–Matthews–Olson protein, and ring deformation in photosystems I and II.
JEDI: A versatile code for strain analysis of molecular and periodic systems under deformation
Authors: Wang Henry , Benter Sanna , Dononelli Wilke , Neudecker Tim
Published: April 2024

Stretching or compression can induce significant energetic, geometric, and spectroscopic changes in materials. To fully exploit these effects in the design of mechano- or piezo-chromic materials, self-healing polymers, and other mechanoresponsive devices, a detailed knowledge about the distribution of mechanical strain in the material is essential. Within the past decade, Judgement of Energy DIstribution (JEDI) analysis has emerged as a useful tool for this purpose. Based on the harmonic approximation, the strain energy in each bond length, bond angle, and dihedral angle of the deformed system is calculated using quantum chemical methods. This allows the identification of the force-bearing scaffold of the system, leading to an understanding of mechanochemical processes at the most fundamental level. Here, we present a publicly available code that generalizes the JEDI analysis, which has previously only been available for isolated molecules. Now, the code has been extended to two- and three-dimensional periodic systems, supramolecular clusters, and substructures of chemical systems under various types of deformation. Due to the implementation of JEDI into the Atomic Simulation Environment, the JEDI analysis can be interfaced with a plethora of program packages that allow the calculation of electronic energies for molecular systems and systems with periodic boundary conditions. The automated generation of a color-coded three-dimensional structure via the Visual Molecular Dynamics program allows insightful visual analyses of the force-bearing scaffold of the strained system.
Top on a smooth plane
Authors: Przybylska Maria , Maciejewski Andrzej J.
Published: April 2024

We investigate the dynamics of a sliding top that is a rigid body with an ideal sharp tip moving in a perfectly smooth horizontal plane, so no friction forces act on the body. We prove that this system is integrable only in two cases analogous to the Euler and Lagrange cases of the classical top problem. The cases with the constant gravity field with acceleration g≠0 and without external field g=0 are considered. The non-integrability proof for g≠0 is based on the fact that the equations of motion for the sliding top are a perturbation of the classical top equations of motion. We show that the integrability of the classical top is a necessary condition for the integrability of the sliding top. Among four integrable classical top cases, the corresponding two cases for the sliding top are also integrable, and for the two remaining cases, we prove their non-integrability by analyzing the differential Galois group of variational equations along a certain particular solution. In the absence of a constant gravitational field g=0, the integrability is much more difficult. First, we proved that if the sliding top problem is integrable, then the body is symmetric. In the proof, we applied the Ziglin theorem concerning the splitting of separatrices phenomenon. Then, we prove the non-integrability of the symmetric sliding top using the differential Galois group of variational equations except two the same as for g≠0 cases. The integrability of these cases is also preserved when we add to equations of motion a gyrostatic term.
Laser control of graphite plate tilting on a magnet surface
Authors: Rodriguez Jacob B. , Fan Qingsong , Yin Yadong , Bardeen Christopher J.
Published: April 2024

When a diamagnetic graphite plate is placed on top of a magnet, it is subject to both magnetic levitation and gravitational forces. Computational modeling is used to demonstrate that these forces can balance each other to allow a stable tilt angle θ to be attained when the graphite plate pivots on the magnet surface. θ depends on the magnetic susceptibility χmag, which can be controlled by using laser irradiation to change the temperature of the graphite. Over a limited temperature range, there is a linear relation between the angle change Δθ and the temperature change ΔT. This predicted behavior is confirmed experimentally using a graphite plate (5 × 5 × 0.83 mm) placed on top of a 7.5 cm diameter neodymium iron boride magnet with a surface field strength of ∼5000 G. Using a 532 nm laser, θ could be continuously tuned from 52° to 26° by varying the laser power between 20 and 800 mW. The response time was about 15 s at all powers. Higher laser powers were observed to lead to a complete loss of levitation, followed by recovery and oscillation in and out of the laser beam. The linear dependence of Δθ on power suggests that photothermal tilting of the graphite plate in a magnetic field provides a fatigue resistant way to achieve large angular deviations using an external light source. This effect can be harnessed to function as a laser-controlled beam steering device.
Possible existence of chiral spin textures in the Bi2Sr2CaCu2O8+δ
/Fe1−
xTbx heterostructure
Authors: Dong Yiqing , Cui Qirui , Liao Menghan , Zhou Hengan , Xu Teng , Qiao Jiabin , Gao Zhiting , Zhao Mengqi , Chopdekar Rajesh V. , Zhang Ding , Yang Hongxin , Jiang Wanjun
Published: April 2024

Toward low-energy-consumption spintronic devices, magnetic multilayers that host chiral spin textures, as well as efficient spin-torques, are highly promising. As compared with resistive materials, superconducting materials are optimal for constructing dissipationless electronic devices, in which the electricity is conducted without producing Joule heating. In this regard, magnetic multilayers containing superconductors are well suited for building ultra-low power spintronic devices. Following this motivation, we study the possible existence of chiral spin textures in the two-dimensional (2D) high temperature superconductor/ferrimagnet heterostructures of stacking order Bi2Sr2CaCu2O8+δ/Fe1−xTbx and stacking order Bi2Sr2CaCu2O8+δ/Co1−xTbx. Through x-ray photon-emission electron microscopy, we observe bubble-like spin textures in a wide temperature range. Based on the first-principles calculations, the important role of spin–orbit interaction from the BiO termination layer is discussed, which induces a very large interfacial Dzyaloshinskii–Moriya interaction and results in the possible existence of chiral spin textures on top of superconductors. Our work suggests that the layered high-temperature superconductor could be incorporated for stabilizing chiral spin textures and for building dissipationless spin-orbitronic devices.
Two-dimensional Thomson scattering measurements of misaligned electron density and temperature gradients and associated Biermann battery produced fields
Authors: Pilgram J. J. , Constantin C. G. , Zhang H. , Tzeferacos P. , Bachmann T. G. , Rovige L. , Heuer P. V. , Adams M. B. P. , Ghazaryan S. , Kaloyan M. , Dorst R. S. , Manuel M. J.-E , Niemann C.
Published: April 2024

We present optical Thomson scattering measurements of electron density and temperature in high Mach number laser-driven blast waves in homogeneous gases. Taylor–Sedov blast waves are launched in nitrogen (N2) or helium (He) at pressures between 0.4 mTorr and 10 Torr by ablating a solid plastic target with a high energy laser pulse (10 J, 1012 W/cm2). Experiments are performed at high repetition rate (1 Hz), which allows one-dimensional and two-dimensional Thomson scattering measurements over an area of several cm2 by automatically translating the scattering volume between shots. Electron temperature and density in the blast wave fronts were seen to increase with increasing background gas pressure. Measured electron density and temperature gradients were used to calculate ∂B/∂t∝∇Te×∇ne. The experimentally measured ∂B/∂t showed agreement with the magnetic field probe (B-dot) measurements, revealing that magnetic fields are generated in the observed blast waves via the Biermann battery effect. The results are compared to numerical three-dimensional collisional magnetohydrodynamic simulations performed with FLASH, and are discussed in the context of spontaneous magnetic field generation via the Biermann battery effect.
Quantitative Expression of the Modified Bragg's Law for Bragg resonances of water waves excited by five types of artificial bars
Authors: Ding Yulong , Liu Huan-Wen , Lin Pengzhi
Published: April 2024

For Class I Bragg resonance excited by five types of finite periodic array of widely spaced bars (rectangular, parabolic, rectified cosinoidal, trapezoidal, and triangular bars), the average phase velocity between any two adjacent bars in each type of bar field has been specifically calculated by employing a mathematical transformation, and therefore, the excitation condition of Class I Bragg resonance excited by each bar field is clarified and the modified Bragg's law established by Xie and Liu becomes a quantitative form. On one hand, if the incident surface wavelength, L, is fixed in advance, then according to the excitation condition, we can directly obtain the critical bar spacing, d, at which Class I Bragg resonance occurs. On the other hand, if the bar spacing, d, is fixed, then according to the excitation condition, we can use an iteration scheme to find out the critical surface wavelength, L, at which Class I Bragg resonance will be excited. In comparison with existing experimental, numerical, and analytical results of Bragg resonance excited by the five types of bar fields, it is shown that the modified Bragg's law is much more accurate than the Bragg's law, and the phenomenon of phase downshift can be well explained. In the linear long-wave limit, owing to the simple dispersion relation, the modified Bragg's law becomes an explicit expression and coincides with Liu's approximate law very well, although the former is a straight line segment while the latter is a curved line segment. Finally, it is shown that the phase downshift of Bragg resonance becomes more significant as the cross-sectional area of bars increases.
Advancing fluid identification via well-logging data: Leveraging persistent initialization and transformer modeling
Authors: Sun Youzhuang , Pang Shanchen , Zhang Yongan
Published: April 2024

In the domain of energy exploration, the forecasting of fluid via well logging is pivotal in directing exploration endeavors. Understanding the composition of fluid underground is key for exploration teams to accurately determine the size, potential reserves, and quality of oil and gas resources. This knowledge is critical in refining exploration tactics and employing resources wisely. We present a novel machine learning architecture termed “PIFormer” for predicting fluid. This design merges Persistence Initialization with a Transformer module. The combination of persistent initialization and Transformer modules is achieved by using the persistent initialization feature representation as input to the Transformer model. Persistent initialization provides a stable starting point, enabling the Transformer model to converge to effective feature representations more rapidly during the learning process. This combination helps address issues in existing methods such as training instability, slow convergence, and local optima problems caused by random initialization. By integrating persistent initialization and the Transformer model, prior knowledge and global information can be more effectively utilized, enhancing the accuracy and robustness of fluid identification. Compared to existing models, the combination of persistent initialization and the Transformer model demonstrates higher accuracy and robustness in fluid identification tasks. Specifically, our approach achieves significant improvements in fluid identification accuracy and outperforms existing models across various types of fluid identification problems. Additionally, our method significantly reduces model training time and improves convergence speed. These results clearly indicate that the combination of persistent initialization and the Transformer model effectively addresses limitations in existing models for fluid identification tasks, providing new avenues and methods for further research and application in this field.