bluuebunny/crossref_metadata_2025 huggingface dataset:
Sacrificial agent effect in piezo-electrocatalytic hydrogen evolution
Authors: Ma Jiangping , Xia Lu , Ruan Lujie , Guan Jingfei , Wang Lushu , Zhang Xingchen , Gao Xingsen , Gan Li-Yong , Zhou Xiaoyuan
Published: May 2023

Piezo-electrocatalysis based on the non-centrosymmetric materials opens an avenue for mechano-to-H2 production through harvesting mechanical energy, being undergoing significant growth. Direct comparison of the performance of various piezo-electrocatalysts is necessary to obtain the optimal candidates for satisfying the demands of practical application but remains a grand challenge because the acquiescently added sacrificial agents vary considerably in the literature. Herein, we systematically investigate the effect of four commonly used types containing totally 15 sacrificial agents on the piezo-electrocatalytic hydrogen evolution by choosing the typical BaTiO3 catalyst as the demo. It is found that the pH, length of the carbon chain, adsorption strength between catalysts and sacrificial agent, and combination of sacrificial agents would impact on the piezo-electrocatalytic H2 evolution performance. Moreover, the self-decomposition effect is found in the sacrificial agent-water mixtures under ultrasonic vibration, implying that H2 can be generated without piezo-electrocatalysts, which was usually ignored. Thus, in this work, a concept of net H2 yield is suggested to standardize the evaluation of piezo-electrocatalysts in future.
Application of the Universal Velocity Profile to rough-wall pipe flow
Authors: Bilgin Eylul , Cantwell Brian J.
Published: May 2023

The universal velocity profile (UVP), defined initially for a smooth pipe, is extended to pipe flow with a rough wall. Data from pipe experiments of fixed roughness fraction and varying Reynolds number are used to formulate a simple correction to the smooth-wall UVP using a function of the roughness Reynolds number. A good fit to the data is achieved using an additive velocity correction combined with a new roughness transition function that accounts for the delayed onset of roughness friction at low roughness Reynolds numbers. It is concluded that the UVP can represent rough-wall pipe flow with a very small error comparable to the smooth-wall case.
Imaging of short-wavelength spin waves in a nanometer-thick YIG/Co bilayer
Authors: Talapatra Abhishek , Qin Huajun , Schulz Frank , Yao Lide , Flajšman Lukáš , Weigand Markus , Wintz Sebastian , van Dijken Sebastiaan
Published: May 2023

We report the imaging of short-wavelength spin waves in a continuous nanometer-thick YIG film with a Co stripe patterned on top. Dynamic dipolar coupling between the YIG film and the Co stripe lowers the spin-wave wavelength when spin waves enter the YIG/Co bilayer region from the bare YIG film, causing partial reflection at the YIG/Co edge. We use time-resolved scanning transmission x-ray microscopy to image the mode conversion process down to a wavelength of 280 nm and extract the spin-wave dispersion, decay length, and magnetic damping in the YIG/Co bilayer. We also analyze spin-wave reflection from the YIG/Co edge and its dependence on the wavelength of incoming and transmitted spin waves.
Voltage-driven ferroelectric domain dynamics in (K,Na)NbO3 investigated by in situ transmission electron microscopy
Authors: Condurache Oana , Dražić Goran , Benčan Andreja
Published: May 2023

Ferroelectric domain dynamics is at the heart of any ferroelectric-based application. In situ transmission electron microscopy (TEM) offers an exciting opportunity to directly image ferroelectric switching and domain dynamics, revealing phenomena that might be concealed in macroscopic measurements. Here, we investigate the voltage-driven response of the mobile, needlelike domains and domain walls (DWs) of a (K,Na)NbO3 single crystal (KNNsc) using in situ TEM in a miniaturized capacitor. Our experimental results reveal that the immobile DWs can act as random bound pinning centers, pinning an area of up to 0.35 μm2. The edge of the sample can promote the nucleation of new domains. Domain growth and coalescence are not always continuous but can be interrupted at a certain voltage in favor of fine domain splitting and the formation of nanoscale domains. Other discontinuities are generated in the functional response when two orthogonal, needlelike domains meet and soft-pinning events occur. These findings shed light on the kinetics of ferroelectric domains and are probably not limited to KNNsc, being applicable to other perovskite-based ferroelectric materials where a needlelike domain morphology is present or where mobile and immobile DWs coexist.
Spin selective charge recombination in chiral donor–bridge–acceptor triads
Authors: Fay Thomas P. , Limmer David T.
Published: May 2023

In this paper, we outline a physically motivated framework for describing spin-selective recombination processes in chiral systems, from which we derive spin-selective reaction operators for recombination reactions of donor–bridge–acceptor molecules, where the electron transfer is mediated by chirality and spin–orbit coupling. In general, the recombination process is selective only for spin-coherence between singlet and triplet states, and it is not, in general, selective for spin polarization. We find that spin polarization selectivity only arises in hopping-mediated electron transfer. We describe how this effective spin-polarization selectivity is a consequence of spin-polarization generated transiently in the intermediate state. The recombination process also augments the coherent spin dynamics of the charge separated state, which is found to have a significant effect on the recombination dynamics and to destroy any long-lived spin polarization. Although we only consider a simple donor–bridge–acceptor system, the framework we present here can be straightforwardly extended to describe spin-selective recombination processes in more complex systems.
Giant enhancement of the Goos–Hänchen shift assisted by merging bound states in the continuum
Authors: Chen Shiwen , Li Zhongfu , Mao Yu , Dai Xiaoyu , Xiang Yuanjiang
Published: May 2023

Bound states in the continuum (BICs) have received considerable attention in the field of nanophotonics due to their highly confined resonance and high Q factor, which effectively eliminates radiation loss. Various periodic structures have been studied to achieve BICs, with photonic crystal slabs (PCSs) being a prominent example. In PCS, multiple BICs can be merged to strongly suppress out-of-plane-scattering losses caused by fabrication imperfections. In this paper, we investigate the impact of reflection-type merging BICs on the Goos–Hänchen shift (GH shift) and demonstrate a remarkable enhancement of the GH shift, exceeding five orders of wavelength. We show the dynamic changes of the GH shifts with the isolated, merging, and merged BICs, achieving positive and negative GH shifts in different angles of peak reflectance for the same frequency. Our research highlights that even minor fabrication imperfections can result in a significant change in the GH shift, which can serve as a means for detecting manufacturing defects. Furthermore, we propose an ultrasensitive environmental refractive index sensor based on the enhanced GH shift by an isolated BIC. Our study contributes to the understanding of BICs and their potential applications in nanophotonics, including advanced optical communication devices, nanodevice fabrication, and highly sensitive sensors.
Slicing Newton spheres with a two-camera 3D imaging system
Authors: Ranathunga Yasashri , Olowolafe Temitayo , Orunesajo Emmanuel , Musah Hackim , Lee Suk Kyoung , Li Wen
Published: May 2023

We demonstrate a simple approach to achieve three-dimensional ion momentum imaging. The method employs two complementary metal–oxide–semiconductor cameras in addition to a standard microchannel plates/phosphor screen imaging detector. The two cameras are timed to measure the decay of luminescence excited by ion hits to extract the time of flight. The achieved time resolution is better than 10 ns, which is mainly limited by camera jitters. A better than 5 ns resolution can be achieved when the jitter is suppressed.
A Lamb wave magnetoelectric antenna design for implantable devices
Authors: Zheng Ruoda , Estrada Victor , Virushabadoss Nishanth , Will-Cole Alexandria , Acosta Adrian , Hu Jinzhao , Yan Wenzhong , Chang Jane P. , Sun Nian X. , Henderson Rashaunda , Carman Gregory P. , Sepulveda Abdon E.
Published: May 2023

A 400 MHz magnetoelectric (ME) Lamb wave antenna design to function in the medical implant communication service band is proposed. The antenna employs a heterostructure of piezoelectric and magnetostrictive membranes to acoustically excite standing shear bulk wave and radiate as a magnetic dipole. Multiphysics finite element analysis simulations are performed for transmission and reception modes. In these simulations, three aspects are investigated: piezoelectricity, micromagnetic precession, and magnetic dipole radiation. An experimental demonstration of the antenna is also conducted and shows mechanical resonance with a Q-factor of 500 and ME coupling. These results indicate that the design can be operated in zero-order antisymmetric (A0) mode as a tunable oscillator or sensor. This ME approach provides a solution to the miniaturization problem of traditional current-based implantable antennas.
Transmission pulse photoacoustic response of thin semiconductor plate
Authors: Stanimirović Zdravko , Stanimirović Ivanka , Galović Slobodanka , Djordjević Katarina , Suljovrujić Edin
Published: May 2023

In modern high-speed semiconductor electronics, there is a high-rate heating of components that is affected by very fast relaxation processes. The relaxation times of these processes should be known for thermal management of these devices. For almost half a century, photoacoustic techniques have been successfully developed and used to investigate physical semiconductor properties. In order to enable observation of fast relaxation processes, the model of pulse photoacoustic signal is proposed that includes influence of thermal relaxations. It is shown that these processes can be observed in a thin semiconductor layer by choosing the frequency of short pulse train and their duty cycle.
Impaired perception of temporal contiguity between action and effect is associated with disorders of agency in schizophrenia
Authors: Roth Manuel J. , Lindner Axel , Hesse Klaus , Wildgruber Dirk , Wong Hong Yu , Buehner Marc J.
Published: May 2023

Delusions of control in schizophrenia are characterized by the striking feeling that one’s actions are controlled by external forces. We here tested qualitative predictions inspired by Bayesian causal inference models, which suggest that such misattributions of agency should lead to decreased intentional binding. Intentional binding refers to the phenomenon that subjects perceive a compression of time between their intentional actions and consequent sensory events. We demonstrate that patients with delusions of control perceived less self-agency in our intentional binding task. This effect was accompanied by significant reductions of intentional binding as compared to healthy controls and patients without delusions. Furthermore, the strength of delusions of control tightly correlated with decreases in intentional binding. Our study validated a critical prediction of Bayesian accounts of intentional binding, namely that a pathological reduction of the prior likelihood of a causal relation between one’s actions and consequent sensory events—here captured by delusions of control—should lead to lesser intentional binding. Moreover, our study highlights the import of an intact perception of temporal contiguity between actions and their effects for the sense of agency.
Farmland practices are driving bird population decline across Europe
Authors: Rigal Stanislas , Dakos Vasilis , Alonso Hany , Auniņš Ainārs , Benkő Zoltán , Brotons Lluís , Chodkiewicz Tomasz , Chylarecki Przemysław , de Carli Elisabetta , del Moral Juan Carlos , Domşa Cristian , Escandell Virginia , Fontaine Benoît , Foppen Ruud , Gregory Richard , Harris Sarah , Herrando Sergi , Husby Magne , Ieronymidou Christina , Jiguet Frédéric , Kennedy John , Klvaňová Alena , Kmecl Primož , Kuczyński Lechosław , Kurlavičius Petras , Kålås John Atle , Lehikoinen Aleksi , Lindström Åke , Lorrillière Romain , Moshøj Charlotte , Nellis Renno , Noble David , Eskildsen Daniel Palm , Paquet Jean-Yves , Pélissié Mathieu , Pladevall Clara , Portolou Danae , Reif Jiří , Schmid Hans , Seaman Benjamin , Szabo Zoltán D. , Szép Tibor , Florenzano Guido Tellini , Teufelbauer Norbert , Trautmann Sven , van Turnhout Chris , Vermouzek Zdeněk , Vikstrøm Thomas , Voříšek Petr , Weiserbs Anne , Devictor Vincent
Published: May 2023

Declines in European bird populations are reported for decades but the direct effect of major anthropogenic pressures on such declines remains unquantified. Causal relationships between pressures and bird population responses are difficult to identify as pressures interact at different spatial scales and responses vary among species. Here, we uncover direct relationships between population time-series of 170 common bird species, monitored at more than 20,000 sites in 28 European countries, over 37 y, and four widespread anthropogenic pressures: agricultural intensification, change in forest cover, urbanisation and temperature change over the last decades. We quantify the influence of each pressure on population time-series and its importance relative to other pressures, and we identify traits of most affected species. We find that agricultural intensification, in particular pesticides and fertiliser use, is the main pressure for most bird population declines, especially for invertebrate feeders. Responses to changes in forest cover, urbanisation and temperature are more species-specific. Specifically, forest cover is associated with a positive effect and growing urbanisation with a negative effect on population dynamics, while temperature change has an effect on the dynamics of a large number of bird populations, the magnitude and direction of which depend on species' thermal preferences. Our results not only confirm the pervasive and strong effects of anthropogenic pressures on common breeding birds, but quantify the relative strength of these effects stressing the urgent need for transformative changes in the way of inhabiting the world in European countries, if bird populations shall have a chance of recovering.
Restoring particulate and mineral-associated organic carbon through regenerative agriculture
Authors: Prairie Aaron M. , King Alison E. , Cotrufo M. Francesca
Published: May 2023

Sustainability of agricultural production and mitigation of global warming rely on the regeneration of soil organic carbon (SOC), in particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) forms. We conducted a global systematic meta-analysis of the effects of regenerative management practices on SOC, POC, and MAOC in cropland, finding: 1) no-till (NT) and cropping system intensification increase SOC (11.3% and 12.4%, respectively), MAOC (8.5% and 7.1%, respectively), and POC (19.7% and 33.3%, respectively) in topsoil (0 to 20 cm), but not in subsoil (>20 cm); 2) experimental duration, tillage frequency, the intensification type, and rotation diversity moderate the effects of regenerative management; and 3) NT synergized with integrated crop–livestock (ICL) systems to greatly increase POC (38.1%) and cropping intensification synergized with ICL systems to greatly increase MAOC (33.1 to 53.6%). This analysis shows that regenerative agriculture is a key strategy to reduce the soil C deficit inherent to agriculture to promote both soil health and long-term C stabilization.
Persistent corotation of the large-scale flow of thermal convection and an immersed free body
Authors: Wang Kaizhe , Zhang Jun
Published: May 2023

Inspired by the superrotation of the Earth’s solid core, we investigate the dynamics of a free-rotating body as it interacts with the large-scale circulation (LSC) of the Rayleigh–Bénard thermal convection in a cylindrical container. A surprising and persistent corotation of both the free body and the LSC emerges, breaking the axial symmetry of the system. The corotational speed increases monotonically with the intensity of thermal convection, measured by the Rayleigh number Ra, which is proportional to the temperature difference between the heated bottom and cooled top. The rotational direction occasionally and spontaneously reverses, occurring more frequently at higher Ra. The reversal events follow a Poisson process; it is feasible that flow fluctuations randomly interrupt and reestablish the rotation-sustaining mechanism. This corotation is powered by thermal convection alone and promoted by the addition of a free body, enriching the classical dynamical system.
Thyroid hormone regulates proximodistal patterning in fin rays
Authors: Harper Melody , Hu Yinan , Donahue Joan , Acosta Benjamin , Dievenich Braes Flora , Nguyen Stacy , Zeng Jenny , Barbaro Julianna , Lee Hyungwoo , Bui Hoa , McMenamin Sarah K.
Published: May 2023

Processes that regulate size and patterning along an axis must be highly integrated to generate robust shapes; relative changes in these processes underlie both congenital disease and evolutionary change. Fin length mutants in zebrafish have provided considerable insight into the pathways regulating fin size, yet signals underlying patterning have remained less clear. The bony rays of the fins possess distinct patterning along the proximodistal axis, reflected in the location of ray bifurcations and the lengths of ray segments, which show progressive shortening along the axis. Here, we show that thyroid hormone (TH) regulates aspects of proximodistal patterning of the caudal fin rays, regardless of fin size. TH promotes distal gene expression patterns, coordinating ray bifurcations and segment shortening with skeletal outgrowth along the proximodistal axis. This distalizing role for TH is conserved between development and regeneration, in all fins (paired and medial), and between
Danio
species as well as distantly related medaka. During regenerative outgrowth, TH acutely induces Shh-mediated skeletal bifurcation. Zebrafish have multiple nuclear TH receptors, and we found that unliganded Thrab—but not Thraa or Thrb—inhibits the formation of distal features. Broadly, these results demonstrate that proximodistal morphology is regulated independently from size-instructive signals. Modulating proximodistal patterning relative to size—either through changes to TH metabolism or other hormone-independent pathways—can shift skeletal patterning in ways that recapitulate aspects of fin ray diversity found in nature.
Cell-type memory in a single-cell eukaryote requires the continuous presence of a specific transcription regulator
Authors: Lee Chien-Der , Ziv Naomi , Johnson Alexander D.
Published: May 2023

A fundamental question in biology is how a eukaryotic cell type can be stably maintained through many rounds of DNA replication and cell division. In this paper, we investigate this question in a fungal species,
Candida albicans
, where two different cells types (white and opaque) arise from the same genome. Once formed, each cell type is stable for thousands of generations. Here, we investigate the mechanisms underlying opaque cell “memory.” Using an auxin-mediated degradation system, we rapidly removed Wor1, the primary transcription activator of the opaque state and, using a variety of methods, determined how long cells can maintain the opaque state. Within approximately 1 h of Wor1 destruction, opaque cells irreversibly lose their memory and switch to the white cell state. This observation rules out several competing models for cell memory and demonstrates that the continuous presence of Wor1 is needed to maintain the opaque cell state—even across a single cell division cycle. We also provide evidence for a threshold concentration of Wor1 in opaque cells, below which opaque cells irreversibly switch to white cells. Finally, we provide a detailed description of the gene expression changes that occur during this switch in cell types.
Spin wavepackets in the Kagome ferromagnet Fe
3
Sn
2
: Propagation and precursors
Authors: Lee Changmin , Sun Yue , Ye Linda , Rathi Sumedh , Wang Kevin , Lu Yuan-Ming , Moore Joel , Checkelsky Joseph G. , Orenstein Joseph
Published: May 2023

The propagation of spin waves in magnetically ordered systems has emerged as a potential means to shuttle quantum information over large distances. Conventionally, the arrival time of a spin wavepacket at a distance,
d
, is assumed to be determined by its group velocity,
v

g

. Here, we report time-resolved optical measurements of wavepacket propagation in the Kagome ferromagnet Fe
3
Sn
2
that demonstrate the arrival of spin information at times significantly less than
d
/
v

g

. We show that this spin wave “precursor” originates from the interaction of light with the unusual spectrum of magnetostatic modes in Fe
3
Sn
2
. Related effects may have far-reaching consequences toward realizing long-range, ultrafast spin wave transport in both ferromagnetic and antiferromagnetic systems.
Deciphering molecular mechanisms stabilizing the reovirus-binding complex
Authors: dos Santos Natividade Rita , Koehler Melanie , Gomes Priscila S. F. C. , Simpson Joshua D. , Smith Sydni Caet , Gomes Diego E. B. , de Lhoneux Juliette , Yang Jinsung , Ray Ankita , Dermody Terence S. , Bernardi Rafael C. , Ogden Kristen M. , Alsteens David
Published: May 2023

Mammalian orthoreoviruses (reoviruses) serve as potential triggers of celiac disease and have oncolytic properties, making these viruses potential cancer therapeutics. Primary attachment of reovirus to host cells is mainly mediated by the trimeric viral protein, σ1, which engages cell-surface glycans, followed by high-affinity binding to junctional adhesion molecule-A (JAM-A). This multistep process is thought to be accompanied by major conformational changes in σ1, but direct evidence is lacking. By combining biophysical, molecular, and simulation approaches, we define how viral capsid protein mechanics influence virus-binding capacity and infectivity. Single-virus force spectroscopy experiments corroborated by in silico simulations show that GM2 increases the affinity of σ1 for JAM-A by providing a more stable contact interface. We demonstrate that conformational changes in σ1 that lead to an extended rigid conformation also significantly increase avidity for JAM-A. Although its associated lower flexibility impairs multivalent cell attachment, our findings suggest that diminished σ1 flexibility enhances infectivity, indicating that fine-tuning of σ1 conformational changes is required to successfully initiate infection. Understanding properties underlying the nanomechanics of viral attachment proteins offers perspectives in the development of antiviral drugs and improved oncolytic vectors.
C. elegans
Clarinet/CLA-1 recruits RIMB-1/RIM-binding protein and UNC-13 to orchestrate presynaptic neurotransmitter release
Authors: Krout Mia , Oh Kelly H. , Xiong Ame , Frankel Elisa B. , Kurshan Peri T. , Kim Hongkyun , Richmond Janet E.
Published: May 2023

Synaptic transmission requires the coordinated activity of multiple synaptic proteins that are localized at the active zone (AZ). We previously identified a
Caenorhabditis elegans
protein named Clarinet (CLA-1) based on homology to the AZ proteins Piccolo, Rab3-interactingmolecule (RIM)/UNC-10 and Fife. At the neuromuscular junction (NMJ),
cla-1 null
mutants exhibit release defects that are greatly exacerbated in
cla-1;unc-10 double
mutants. To gain insights into the coordinated roles of CLA-1 and UNC-10, we examined the relative contributions of each to the function and organization of the AZ. Using a combination of electrophysiology, electron microscopy, and quantitative fluorescence imaging we explored the functional relationship of CLA-1 to other key AZ proteins including: RIM1, Cav2.1 channels, RIM1-binding protein, and Munc13 (
C. elegans
UNC-10, UNC-2, RIMB-1 and UNC-13, respectively). Our analyses show that CLA-1 acts in concert with UNC-10 to regulate UNC-2 calcium channel levels at the synapse via recruitment of RIMB-1. In addition, CLA-1 exerts a RIMB-1-independent role in the localization of the priming factor UNC-13. Thus
C. elegans
CLA-1/UNC-10 exhibit combinatorial effects that have overlapping design principles with other model organisms: RIM/RBP and RIM/ELKS in mouse and Fife/RIM and BRP/RBP in
Drosophila
. These data support a semiconserved arrangement of AZ scaffolding proteins that are necessary for the localization and activation of the fusion machinery within nanodomains for precise coupling to Ca
2+
channels.
Photoelectron spectroscopy with entangled photons; enhanced spectrotemporal resolution
Authors: Gu Bing , Sun Shichao , Chen Feng , Mukamel Shaul
Published: May 2023

In this theoretical study, we show how photoelectron signals generated by time-energy entangled photon pairs can monitor ultrafast excited state dynamics of molecules with high joint spectral and temporal resolutions, not limited by the Fourier uncertainty of classical light. This technique scales linearly, rather than quadratically, with the pump intensity, allowing the study of fragile biological samples with low photon fluxes. Since the spectral resolution is achieved by electron detection and the temporal resolution by a variable phase delay, this technique does not require scanning the pump frequency and the entanglement times, which significantly simplifies the experimental setup, making it feasible with current instrumentation. Application is made to the photodissociation dynamics of pyrrole calculated by exact nonadiabatic wave packet simulations in a reduced two nuclear coordinate space. This study demonstrates the unique advantages of ultrafast quantum light spectroscopy.
A self-inactivating invertebrate opsin optically drives biased signaling toward Gβγ-dependent ion channel modulation
Authors: Tsukamoto Hisao , Kubo Yoshihiro
Published: May 2023

Animal opsins, light-sensitive G protein-coupled receptors, have been used for optogenetic tools to control G protein-dependent signaling pathways. Upon G protein activation, the Gα and Gβγ subunits drive different intracellular signaling pathways, leading to complex cellular responses. For some purposes, Gα- and Gβγ-dependent signaling needs to be separately modulated, but these responses are simultaneously evoked due to the 1:1 stoichiometry of Gα and Gβγ Nevertheless, we show temporal activation of G protein using a self-inactivating invertebrate opsin,
Platynereis
c-opsin1, drives biased signaling for Gβγ-dependent GIRK channel activation in a light-dependent manner by utilizing the kinetic difference between Gβγ-dependent and Gα-dependent responses. The opsin-induced transient Gi/o activation preferentially causes activation of the kinetically fast Gβγ-dependent GIRK channels rather than slower Gi/oα-dependent adenylyl cyclase inhibition. Although similar Gβγ-biased signaling properties were observed in a self-inactivating vertebrate visual pigment,
Platynereis
c-opsin1 requires fewer retinal molecules to evoke cellular responses. Furthermore, the Gβγ-biased signaling properties of
Platynereis
c-opsin1 are enhanced by genetically fusing with RGS8 protein, which accelerates G protein inactivation. The self-inactivating invertebrate opsin and its RGS8-fusion protein can function as optical control tools biased for Gβγ-dependent ion channel modulation.
The SHDRA syndrome-associated gene
TMEM260
encodes a protein-specific O-mannosyltransferase
Authors: Larsen Ida Signe Bohse , Povolo Lorenzo , Zhou Luping , Tian Weihua , Mygind Kasper Johansen , Hintze John , Jiang Chen , Hartill Verity , Prescott Katrina , Johnson Colin A. , Mullegama Sureni V. , McConkie-Rosell Allyn , McDonald Marie , Hansen Lars , Vakhrushev Sergey Y. , Schjoldager Katrine T. , Clausen Henrik , Worzfeld Thomas , Joshi Hiren J. , Halim Adnan
Published: May 2023

Mutations in the
TMEM260
gene cause structural heart defects and renal anomalies syndrome, but the function of the encoded protein remains unknown. We previously reported wide occurrence of O-mannose glycans on extracellular immunoglobulin, plexin, transcription factor (IPT) domains found in the hepatocyte growth factor receptor (cMET), macrophage-stimulating protein receptor (RON), and plexin receptors, and further demonstrated that two known protein O-mannosylation systems orchestrated by the POMT1/2 and transmembrane and tetratricopeptide repeat-containing proteins 1-4 gene families were not required for glycosylation of these IPT domains. Here, we report that the
TMEM260
gene encodes an ER-located protein O-mannosyltransferase that selectively glycosylates IPT domains. We demonstrate that disease-causing
TMEM260
mutations impair O-mannosylation of IPT domains and that
TMEM260
knockout in cells results in receptor maturation defects and abnormal growth of 3D cell models. Thus, our study identifies the third protein-specific O-mannosylation pathway in mammals and demonstrates that O-mannosylation of IPT domains serves critical functions during epithelial morphogenesis. Our findings add a new glycosylation pathway and gene to a growing group of congenital disorders of glycosylation.
Engineering Knill–Laflamme–Milburn Entanglement via Dissipation and Coherent Population Trapping in Rydberg Atoms
Authors: Li Rui , He Shuang , Meng Zhi-Jun , Jin Zhao , Gong Wei-Jiang
Published: May 2023

We present a scheme for dissipatively preparing bipartite Knill–Laflamme–Milburn (KLM) entangled state in a neutral atom system, where the spontaneous emission of excited Rydberg states, combined with the coherent population trapping, is actively exploited to engineer a steady KLM state from an arbitrary initial state. Instead of commonly used antiblockade dynamics of two Rydberg atoms, we particularly utilize the Rydberg–Rydberg interaction as the pumping source to drive the undesired states so that it is unnecessary to satisfy a certain relation with laser detuning. The numerical simulation of the master equation signifies that both the fidelity and the purity above 98% is available with the current feasible parameters, and the corresponding steady-state fidelity is robust to the variations of the dynamical parameters.
Influence of mixed-frequency medium-voltage and environmental stress on the aging of epoxy
Authors: Küchler Florian , Färber Raphael , Šefl Ondřej , Bill Fabian , Franck Christian M
Published: May 2023

Recent developments in power electronic technologies lead to new challenges for insulation systems. This contribution aims to clarify the influence of a broad range of mixed-frequency (MF) medium-voltage and environmental stress parameters on the aging of epoxy insulation. For this purpose, test samples are stressed with an AC (50 Hz) or a DC voltage, superimposed with a pulse-width-modulated (PWM) voltage (kHz range). An analysis of the samples’ health state is carried out after the aging by the evaluation of potential aging markers (AC breakdown strength, dielectric permittivity, glass transition temperature, Fourier-transform infrared spectroscopy spectra). Although the main focus of this work is on aging below the inception of partial discharges (PDs), it was first confirmed that PD-related aging depends mainly on the peak voltage stress. In contrast, the results obtained by aging below PD inception suggests a dependence on the root-mean-square of the applied voltage stress, and consequently on the energy dissipation. Aging in the PD-free regime was only observed at alternating electric field stress and high relative humidity or elevated temperatures. No influences of space charge and of the slew rate of the PWM voltage were observed. Remarkably, higher PWM frequencies lead to less insulation aging. This might be attributed to the increasing hindrance of polymer side chain movement at higher frequencies, as observed by dielectric spectroscopy. In addition, it is indicated that the aging mechanisms under MF voltage stress result from superimposed single-frequency aging mechanisms and that aging is activated after a latency period. Of the investigated potential aging markers, only the residual breakdown strength revealed aging effects, which correlates with lifetime observations in the PD-free voltage stress regime. It is hypothesized that the aging mechanism is associated with a rearrangement of the free volume in the polymer, followed by a localized breaking of van der Waals bonds.
An alternative simulation approach for surface flashover in a vacuum using a 1D2V continuum and kinetic model
Authors: Sun Guang-Yu , Lian Ru-Hui , Zhang Shu , Yang Xiong , Abbas Muhammad Farasat , Wang Chao , Guo Bao-Hong , Song Bai-Peng , Zhang Guan-Jun
Published: May 2023

Surface flashover across an insulator in a vacuum is a destructive plasma discharge which undermines the behaviors of a range of applications in electrical engineering, particle physics and space engineering, etc. This phenomenon is widely modeled by the particle-in-cell (PIC) simulation, here the continuum and kinetic simulation method is first proposed and implemented as an alternative solution for flashover modeling, aiming for the prevention of unfavorable particle noises in PIC models. A one dimension in space, two dimensions in velocity kinetic simulation model is constructed. Modeling setup, physical assumptions, and simulation algorithm are presented in detail, and a comparison with the well-known secondary electron (SE) emission avalanche analytical expression and existing PIC simulation are made. The obtained kinetic simulation results are consistent with the analytical prediction, and feature noise-free data of surface charge density as well as fluxes of primary and SEs. Discrepancies between the two simulation models and analytical predictions are explained. The code is convenient for updating and to include additional physical processes. The possible implementations of outgassing and plasma species for the final breakdown stage are discussed. The proposed continuum and kinetic approach are expected to inspire future modeling studies for the flashover mechanism and mitigation.
Implications of phonon anisotropy on thermal conductivity of fluorite oxides
Authors: Adnan Saqeeb , Jin Miaomiao , Bryan Matthew S , Manley Michael E , Hurley David H , Khafizov Marat
Published: May 2023

Fluorite oxides are attractive ionic compounds for a range of applications with critical thermal management requirements. In view of recent reports alluding to anisotropic thermal conductivity in this face-centered cubic crystalline systems, we perform a detailed analysis of the impact of direction-dependent phonon group velocities and lifetimes on the thermal transport of fluorite oxides. We demonstrate that the bulk thermal conductivity of this class of materials remains isotropic despite notable anisotropy in phonon lifetime and group velocity. However, breaking the symmetry of the phonon lifetime under external stimuli including boundary scattering present in nonequilibrium molecular dynamics simulations of finite size simulation cell gives rise to apparent thermal conductivity anisotropy. We observe that for accurate determination of thermal conductivity, it is important to consider phonon properties not only along high symmetry directions commonly measured in inelastic neutron or x-ray scattering experiments but also of those along lower symmetry. Our results suggests that certain low symmetry directions have a larger contribution to thermal conductivity compared to high symmetry ones.
Secondary electron emission from magnetron targets
Authors: Buschhaus R , von Keudell A
Published: May 2023

Ion-induced secondary electron emission of surfaces occurs in all gas discharges which have contact to surfaces such as electrodes or chamber walls. These secondary electrons (SEs) play an important role, for instance, in the performance of DC discharges, RF discharges and magnetron sputtering discharges. SE generation can be separated into potential electron emission (PEE) due to the neutralization of the incident ion upon impact and kinetic electron emission (KEE) due to the electronic stopping of the penetrating ion in the solid. SE due to neutralization is usually described by Auger processes and the density of states of the electrons in the solid, whereas KEE scales with the electronic stopping of the ion in the solid, as being calculated by ion collision simulations. The measurement of the energy distribution of the SEs of three metals (Al, Ti, Cu) and their oxides reveals the occurrence of Auger peaks, which are not reflected by standard models such as the Hagstrum model. Instead, in this paper, a model is proposed describing these Auger peaks by Auger neutralization of holes created by the collision cascade of the incident ion. This shows decent agreement. The contribution of Auger peaks in the metals Al and Ti is very significant, whereas it is negligible in the case of Cu. The implication of these energy distributions to the performance of magnetron sputtering discharges is discussed.
The formation of O and H radicals in a pulsed discharge in atmospheric pressure helium with water vapour admixtures
Authors: Brisset Alexandra , Bieniek Matthew , Invernizzi Laurent , Hasan Mohammad , Walsh James , Niemi Kari , Wagenaars Erik
Published: May 2023

The spatio-temporal distribution of O and H radicals in a 90 ns pulsed discharge, generated in a pin–pin geometry with a 2.2 mm gap, in He + H2O (0.1% and 0.25%), is studied both experimentally and by 1D fluid modelling. The density of O and H radicals as well as the effective lifetimes of their excited states are measured using picosecond resolution two-photon absorption laser induced fluorescence. Good agreement between experiments and modelling is obtained for the species densities. The density of O and H is found to be homogenous along the discharge axis. Even though the high voltage pulse is 90 ns long, the density of O peaks only about 1 μs after the end of the current pulse, reaching 2 × 1016 cm−3 at 0.1% H2O. It then remains nearly constant over 10 μs before decaying. Modelling indicates that the electron temperature (Te) in the centre of the vessel geometry ranges from 6 to 4 eV during the peak of discharge current, and after 90 ns, drops below 0.5 eV in about 50 ns. Consequently, during the discharge (<100 ns), O is predominantly produced by direct dissociation of O2 by electron impact, and in the early afterglow (from 100 ns to 1 μs) O is produced by dissociative recombination of O2
+. The main loss mechanism of O is initially electron impact ionisation and once T
e has dropped, it becomes mainly Penning ionisation with He2* and He* as well as three-body recombination with O+ and He. On time scales of 100–200 μs, O is mainly lost by radial diffusion. The production of H shows a similar behaviour, reaching 0.45 × 1016 cm−3 at 1 μs, due to direct dissociation of H2O by electron impact (<100 ns) followed by electron–ion recombination processes (from 200 ns to 1.5 us). H is dominantly lost through Penning ionisation with He* and He2* and by electron impact ionisation, and by charge exchange with O+. Increasing concentrations of water vapour, from 0.1% to 0.25%, have little effect on the nature of the processes of H formation but trigger a stronger initial production of O, which is not currently reproduced satisfactorily by the modelling. What emerges from this study is that the built up of O and H densities in pulsed discharges continues after electron-impact dissociation processes with additional afterglow processes, not least through the dissociative recombination of O2
+ and H2
+.
On-demand harmonic wave suppression in non-Hermitian space-time-periodic phased arrays
Authors: Adlakha R , Nouh M
Published: May 2023

Phased arrays have been a cornerstone of non-destructive evaluation, sonar communications, and medical imaging for years. Conventional arrays work by imparting a static phase gradient across a set of transducers to steer a self-created wavefront in a desired direction. Most recently, space-time-periodic (STP) phased arrays have been explored in the context of multi-harmonic wave beaming. Owing to the STP phase profile, multiple scattered harmonics of a single-frequency input are generated which propagate simultaneously in different directional lanes. Each of these lanes is characterized by a principal angle and a distinct frequency signature that can be computationally predicted. However, owing to the Hermitian (real) nature of the spatiotemporal phase gradient, waves emergent from the array are still bound to propagate simultaneously along up- and down-converted directions with a perfectly symmetric energy distribution. Seeking to push this boundary, this paper presents a class of non-Hermitian STP phased arrays which exercise a degree of unprecedented control over the transmitted waves through an interplay between gain, loss, and coupling between its individual components. A complex phase profile under two special symmetries, parity-time (PT) and anti-PT, is introduced that enables the modulation of the amplitude of various harmonics and decouples up- and down-converted harmonics of the same order. We show that these arrays provide on-demand suppression of either up- or down-converted harmonics at an exceptional point—a degeneracy in the parameter space where the system’s eigenvalues and eigenvectors coalesce. An experimental prototype of the non-Hermitian array is constructed to illustrate the selective directional suppression via time-transient measurements of the out-of-plane displacements of an elastic substrate via laser vibrometry. The theory of non-Hermitian phased arrays and their experimental realization unlock rich opportunities in precise elastoacoustic wave manipulation that can be tailored for a diverse range of engineering applications.
Broadband X-Ray Spectral Analysis of the ULX NGC 1313 X-1 Using JeTCAF: Origin of the ULX Bubble
Authors: Palit Biswaraj , Mondal Santanu
Published: May 2023

NGC 1313 X-1 is a mysterious ultraluminous X-ray (ULX) source whose X-ray-powering mechanism and bubble-like structure surrounding the source are topics of intense study. Here, we perform an X-ray spectroscopic study of the source using joint XMM-Newton and NuSTAR observations taken during 2012–2017. The combined spectra cover the energy band 0.3–20 keV. We use the accretion–ejection-based JeTCAF model for spectral analysis. The model-fitted disk mass accretion rate varies from 4.6 to 9.6

M

̇

Edd

and the halo mass accretion rate varies from 4.0 to 6.1

M

̇

Edd

with a dynamic Comptonizing corona of average size of ∼15 r

g
. The data fitting is carried out for different black hole (BH) mass values. The goodness of the fit and uncertainties in model parameters improve while using higher BH masses, with the most probable mass of the compact object being 133 ± 33 M
⊙. We have estimated the mass outflow rate, its velocity and power, and the age of the inflated bubble surrounding the source. Our estimated bubble morphology is in accordance with the observed optical bubble and winds found through high-resolution X-ray spectroscopy, suggesting that the bubble was expanded by the outflows originating from the central source. Finally, we conclude that the super-Eddington accretion onto a nearly intermediate-mass BH may power a ULX when the accretion efficiency is low, though their efficiency increases when the jet/outflow is taken into account, in agreement with numerical simulations in the literature.
Fractal-Thermodynamic system analogy and complexity of plant leaves
Authors: Vishnu M , Jaishanker R
Published: May 2023

More precise measurements of the complexity of leaf shapes can open new pathways to understanding plant adaptation and resilience in the face of global changes. We present a method to measure the complexity of plant leaf shapes by relating their fractal dimension to topological entropy. Our method relies on ‘segmental fractal complexity’ and stems from a fractal-thermodynamic system analogy. The complexity of plant leaf shapes is an algebraic combination of the fractal dimension of the components, leaf lamina, background, and leaf edge. We applied this method to leaf forms of 42 tropical plant species. Segmental fractal complexity is an improvement over the leaf dissection index because of its ability to capture the spatial positioning of a leaf’s lamina, edge, and background. It is also an advancement over conventional geometric and fractal dimension-based measures of leaf complexity because it does not entail information loss due to the pre-processing and is perceptibly simple.
Interpretable machine learning model to predict survival days of malignant brain tumor patients
Authors: Rajput Snehal , Kapdi Rupal A , Raval Mehul S , Roy Mohendra
Published: May 2023

An artificial intelligence (AI) model’s performance is strongly influenced by the input features. Therefore, it is vital to find the optimal feature set. It is more crucial for the survival prediction of the glioblastoma multiforme (GBM) type of brain tumor. In this study, we identify the best feature set for predicting the survival days (SD) of GBM patients that outrank the current state-of-the-art methodologies. The proposed approach is an end-to-end AI model. This model first segments tumors from healthy brain parts in patients’ MRI images, extracts features from the segmented results, performs feature selection, and makes predictions about patients’ survival days (SD) based on selected features. The extracted features are primarily shape-based, location-based, and radiomics-based features. Additionally, patient metadata is also included as a feature. The selection methods include recursive feature elimination, permutation importance (PI), and finding the correlation between the features. Finally, we examined features’ behavior at local (single sample) and global (all the samples) levels. In this study, we find that out of 1265 extracted features, only 29 dominant features play a crucial role in predicting patients’ SD. Among these 29 features, one is metadata (age of patient), three are location-based, and the rest are radiomics features. Furthermore, we find explanations of these features using post-hoc interpretability methods to validate the model’s robust prediction and understand its decision. Finally, we analyzed the behavioral impact of the top six features on survival prediction, and the findings drawn from the explanations were coherent with the medical domain. We find that after the age of 50 years, the likelihood of survival of a patient deteriorates, and survival after 80 years is scarce. Again, for location-based features, the SD is less if the tumor location is in the central or back part of the brain. All these trends derived from the developed AI model are in sync with medically proven facts. The results show an overall 33% improvement in the accuracy of SD prediction compared to the top-performing methods of the BraTS-2020 challenge.
MIST reunited
Authors: Woodfield Emma , Smith Andy , Daggitt Thomas , Turner Harriet
Published: May 2023

Emma Woodfield, Andy Smith and colleagues outline the research presented and discussed at the Autumn MIST meeting in November 2022
The Need for Practicable Normative Right-based Social Work Practice in Secure and Forensic Mental Health Services
Authors: Markham Sarah
Published: May 2023

We (both author and reader) will explore the need to develop a practicable evaluative human rights-based approach to the care, treatment and discharge of forensic mental health patients. It can be argued that patients in secure and forensic services are potentially the most marginalised and extensively stigmatised of all patient cohorts, and that the extent to which they are discriminated against should not be underestimated. We will consider the concept of right-based practice in secure and forensic mental health settings, and how the quality of practice can be strengthened. We will ground our exploration in the lived experiences of secure and forensic mental health patients and seek through the lens of lived experience to envisage what could constitute fairer and more supportive systems of care.