bluuebunny/crossref_metadata_2025_split huggingface dataset:
Jupiter's Double‐Arc Aurora as a Signature of Magnetic Reconnection: Simultaneous Observations From HST and Juno
Authors: Guo R. L. , Yao Z. H. , Grodent D. , Bonfond B. , Clark G. , Dunn W. R. , Palmaerts B. , Mauk B. H. , Vogt M. F. , Shi Q. Q. , Wei Y. , Connerney J. E. P. , Bolton S. J. 
Published: July 2021

AbstractJupiter's powerful auroral emission is usually divided into the polar, main, and equatorward components. The driver of Jupiter's main aurora is a central question for the community. Previous investigations reveal many distinct substructures on the main auroral oval, which are indicators of fundamentally different magnetospheric processes. Understanding these substructures could provide key constraints for uncovering the driver of Jupiter's main aurora emission. In this study, we show the evolution of a double‐auroral arc on the dawnside from observations by the Hubble Space Telescope (HST). Simultaneous in situ observations from the Juno spacecraft provide direct evidence of magnetic reconnection and magnetic dipolarization. By analyzing the datasets from Juno and HST, we suggest that the evolution of the double‐arc structure is likely a consequence of the non‐steady progress of magnetic reconnection.
Stress Transfer Along the Western Boundary of the Bayan Har Block on the Tibet Plateau From the 2008 to 2020 Yutian Earthquake Sequence in China
Authors: Jia Ke , Zhou Shiyong , Zhuang Jiancang , Jiang Changsheng 
Published: July 2021

AbstractEight Ml ≥ 7.0 earthquakes have occurred around the Bayan Har block, NW Tibet, China, since 2000, resulting in a large number of casualties. Near the western boundary of the Bayan Har block, four Ml ≥ 6.0 Yutian earthquakes have occurred from 2008 to 2020. Stress interactions among them are comprehensively investigated by applying the ETAS (Epidemic‐Type Aftershock Sequence) model and calculating(Coulomb failure stress change) from a 3D linear viscoelastic mode. The combined (coseismic plus postseismic)induced by proceeding Yutian earthquakes on hypocenters of the 2012, 2014, and 2020 Yutian earthquakes are −1.5 × 10−4, 3.6 × 10−3, and 1.5 × 10−1 MPa, respectively. The background probabilities of the 2008, 2012, 2014, and 2020 Yutian earthquakes are 0.87, 0.97, 1.5 × 10−3, and 8.7 × 10−5, respectively. Combining those two independent approaches, we conclude that the 2008 and 2012 Yutian earthquakes are more like background earthquakes and that the 2014 and 2020 Yutian earthquakes were triggered by the proceeding Yutian earthquakes.
A Distinct Class of High Peak‐Current Lightning Pulses Over Mountainous Terrain in Thunderstorms
Authors: Lyu Fanchao , Cummer Steven A. , Krehbiel Paul R. , Rison William , Bruning Eric C. , Rutledge Steven A. 
Published: July 2021

AbstractCloud‐to‐ground strokes, narrow bipolar events, and energetic in‐cloud pulses are known classes of high peak‐current lightning processes that occur in thunderstorms. Here, we report one more distinct class of high peak‐current events observed exclusively over mountainous terrain, usually above 2,000 m altitude, in the continental Unites States. These events, which we call mountain‐top energetic pulses (MEPs), are bipolar pulses with negative radiated field polarities. MEPs are generated between the high mountain tops and compact overhead thunderclouds. Evidence supports the hypothesis that MEPs are produced by terrain‐initiated upward positive leaders propagating in high electric fields due to the proximity of the low negative charge regions of the thunderstorms. This scenario further suggests the possibility that MEPs are associated with downward terrestrial gamma‐ray flashes, and their high peak currents imply that they may produce elves.
Turbulence and Intermittency in the Winter Cusp Ionosphere Studied With the ICI Sounding Rockets
Authors: Di Mare F. , Spicher A. , Clausen L. B. N. , Miloch W. J. , Moen J. I. 
Published: July 2021

AbstractThe characteristics of turbulent plasma in the winter cusp ionosphere is studied based on in‐situ data from the Investigation of Cusp Irregularities (ICI) sounding rockets. The electron density fluctuations from ICI‐2 and ICI‐3 missions have been analyzed for the whole flight, using advanced time‐series analysis techniques. The analysis of the autocorrelation scale is indicative of the turbulence integral scale and marks the onset of the turbulent cascade from large to small scales in the power spectrum density of the rocket data. The power spectrum is typical for a turbulent field. The turbulent structures are persistent in the data, which are quantified by analyzing the Probability Distribution Functions (PDFs) and their deviations from the Gaussian distribution. The kurtosis analysis indicates the presence of intermittency. These results are compared with the Local Intermittence Measure ‐ LIM, which confirms the presence of small scale intermittent structures. The turbulence measured by rockets appears well developed and covers frequencies between 1 Hz and several hundred Hz. There is a good agreement with the previous results, suggesting that density fluctuations in the ionospheric cusp agree with the turbulence framework in which intermittent processes transfer energy across different scales.
GPX4 and vitamin E cooperatively protect hematopoietic stem and progenitor cells from lipid peroxidation and ferroptosis
Authors: Hu Qian , Zhang Yifan , Lou Huiling , Ou Zexian , Liu Jin , Duan Wentao , Wang Hao , Ge Yuanlong , Min Junxia , Wang Fudi , Ju Zhenyu 
Published: July 2021

AbstractFerroptosis, a newly defined mode of regulated cell death caused by unbalanced lipid redox metabolism, is implicated in various tissue injuries and tumorigenesis. However, the role of ferroptosis in stem cells has not yet been investigated. Glutathione peroxidase 4 (GPX4) is a critical suppressor of lipid peroxidation and ferroptosis. Here, we study the function of GPX4 and ferroptosis in hematopoietic stem and progenitor cells (HSPCs) in mice with Gpx4 deficiency in the hematopoietic system. We find that Gpx4 deletion solely in the hematopoietic system has no significant effect on the number and function of HSPCs in mice. Notably, hematopoietic stem cells (HSCs) and hematopoietic progenitor cells lacking Gpx4 accumulated lipid peroxidation and underwent ferroptosis in vitro. α-Tocopherol, the main component of vitamin E, was shown to rescue the Gpx4-deficient HSPCs from ferroptosis in vitro. When Gpx4 knockout mice were fed a vitamin E-depleted diet, a reduced number of HSPCs and impaired function of HSCs were found. Furthermore, increased levels of lipid peroxidation and cell death indicated that HSPCs undergo ferroptosis. Collectively, we demonstrate that GPX4 and vitamin E cooperatively maintain lipid redox balance and prevent ferroptosis in HSPCs.
Controlled multi-photon subtraction with cascaded Rydberg superatoms as single-photon absorbers
Authors: Stiesdal Nina , Busche Hannes , Kleinbeck Kevin , Kumlin Jan , G. Hansen Mikkel , Büchler Hans Peter , Hofferberth Sebastian 
Published: July 2021

AbstractThe preparation of light pulses with well-defined quantum properties requires precise control at the individual photon level. Here, we demonstrate exact and controlled multi-photon subtraction from incoming light pulses. We employ a cascaded system of tightly confined cold atom ensembles with strong, collectively enhanced coupling of photons to Rydberg states. The excitation blockade resulting from interactions between Rydberg atoms limits photon absorption to one per ensemble and rapid dephasing of the collective excitation suppresses stimulated re-emission of the photon. We experimentally demonstrate subtraction with up to three absorbers. Furthermore, we present a thorough theoretical analysis of our scheme where we identify weak Raman decay of the long-lived Rydberg state as the main source of infidelity in the subtracted photon number and investigate the performance of the multi-photon subtractor for increasing absorber numbers in the presence of Raman decay.
Copper catalyzed late-stage C(sp3)-H functionalization of nitrogen heterocycles
Authors: Chang Zhe , Huang Jialin , Wang Si , Chen Geshuyi , Zhao Heng , Wang Rui , Zhao Depeng 
Published: July 2021

AbstractNitrogen heterocycle represents a ubiquitous skeleton in natural products and drugs. Late-stage C(sp3)-H bond functionalization of N-heterocycles with broad substrate scope remains a challenge and of particular significance to modern chemical synthesis and pharmaceutical chemistry. Here, we demonstrate copper-catalysed late-stage C(sp3)-H functionalizaion of N-heterocycles using commercially available catalysts under mild reaction conditions. We have investigated 8 types of N-heterocycles which are usually found as medicinally important skeletons. The scope and utility of this approach are demonstrated by late-stage C(sp3)-H modification of these heterocycles including a number of pharmaceuticals with a broad range of nucleophiles, e.g. methylation, arylation, azidination, mono-deuteration and glycoconjugation etc. Preliminary mechanistic studies reveal that the reaction undergoes a C-H fluorination process which is followed by a nucleophilic substitution.
Highly accurate protein structure prediction with AlphaFold
Authors: Jumper John , Evans Richard , Pritzel Alexander , Green Tim , Figurnov Michael , Ronneberger Olaf , Tunyasuvunakool Kathryn , Bates Russ , Žídek Augustin , Potapenko Anna , Bridgland Alex , Meyer Clemens , Kohl Simon A. A. , Ballard Andrew J. , Cowie Andrew , Romera-Paredes Bernardino , Nikolov Stanislav , Jain Rishub , Adler Jonas , Back Trevor , Petersen Stig , Reiman David , Clancy Ellen , Zielinski Michal , Steinegger Martin , Pacholska Michalina , Berghammer Tamas , Bodenstein Sebastian , Silver David , Vinyals Oriol , Senior Andrew W. , Kavukcuoglu Koray , Kohli Pushmeet , Hassabis Demis 
Published: July 2021

AbstractProteins are essential to life, and understanding their structure can facilitate a mechanistic understanding of their function. Through an enormous experimental effort1–4, the structures of around 100,000 unique proteins have been determined5, but this represents a small fraction of the billions of known protein sequences6,7. Structural coverage is bottlenecked by the months to years of painstaking effort required to determine a single protein structure. Accurate computational approaches are needed to address this gap and to enable large-scale structural bioinformatics. Predicting the three-dimensional structure that a protein will adopt based solely on its amino acid sequence—the structure prediction component of the ‘protein folding problem’8—has been an important open research problem for more than 50 years9. Despite recent progress10–14, existing methods fall far short of atomic accuracy, especially when no homologous structure is available. Here we provide the first computational method that can regularly predict protein structures with atomic accuracy even in cases in which no similar structure is known. We validated an entirely redesigned version of our neural network-based model, AlphaFold, in the challenging 14th Critical Assessment of protein Structure Prediction (CASP14)15, demonstrating accuracy competitive with experimental structures in a majority of cases and greatly outperforming other methods. Underpinning the latest version of AlphaFold is a novel machine learning approach that incorporates physical and biological knowledge about protein structure, leveraging multi-sequence alignments, into the design of the deep learning algorithm.
Dataset of cortical activity recorded with high spatial resolution from anesthetized rats
Authors: Horváth Csaba , Tóth Lili Fanni , Ulbert István , Fiáth Richárd 
Published: July 2021

AbstractPublicly available neural recordings obtained with high spatial resolution are scarce. Here, we present an electrophysiological dataset recorded from the neocortex of twenty rats anesthetized with ketamine/xylazine. The wideband, spontaneous recordings were acquired with a single-shank silicon-based probe having 128 densely-packed recording sites arranged in a 32 × 4 array. The dataset contains the activity of a total of 7126 sorted single units extracted from all layers of the cortex. Here, we share raw neural recordings, as well as spike times, extracellular spike waveforms and several properties of units packaged in a standardized electrophysiological data format. For technical validation of our dataset, we provide the distributions of derived single unit properties along with various spike sorting quality metrics. This large collection of in vivo data enables the investigation of the high-resolution electrical footprint of cortical neurons which in turn may aid their electrophysiology-based classification. Furthermore, the dataset might be used to study the laminar-specific neuronal activity during slow oscillation, a brain rhythm strongly involved in neural mechanisms underlying memory consolidation and sleep.
Estimation of unsteady hydromagnetic Williamson fluid flow in a radiative surface through numerical and artificial neural network modeling
Authors: Shafiq Anum , Çolak Andaç Batur , Sindhu Tabassum Naz , Al-Mdallal Qasem M. , Abdeljawad T. 
Published: July 2021

AbstractIn current investigation, a novel implementation of intelligent numerical computing solver based on multi-layer perceptron (MLP) feed-forward back-propagation artificial neural networks (ANN) with the Levenberg–Marquard algorithm is provided to interpret heat generation/absorption and radiation phenomenon in unsteady electrically conducting Williamson liquid flow along porous stretching surface. Heat phenomenon is investigated by taking convective boundary condition along with both velocity and thermal slip phenomena. The original nonlinear coupled PDEs representing the fluidic model are transformed to an analogous nonlinear ODEs system via incorporating appropriate transformations. A data set for proposed MLP-ANN is generated for various scenarios of fluidic model by variation of involved pertinent parameters via Galerkin weighted residual method (GWRM). In order to predict the (MLP) values, a multi-layer perceptron (MLP) artificial neural network (ANN) has been developed. There are 10 neurons in hidden layer of feed forward (FF) back propagation (BP) network model. The predictive performance of ANN model has been analyzed by comparing the results obtained from the ANN model using Levenberg-Marquard algorithm as the training algorithm with the target values. When the obtained Mean Square Error (MSE), Coefficient of Determination (R) and error rate values have been analyzed, it has been concluded that the ANN model can predict SFC and NN values with high accuracy. According to the findings of current analysis, ANN approach is accurate, effective and conveniently applicable for simulating the slip flow of Williamson fluid towards the stretching plate with heat generation/absorption. The obtained results showed that ANNs are an ideal tool that can be used to predict Skin Friction Coefficients and Nusselt Number values.
Correlation between human health and reactive oxygen species produced in blood: a long-term chemiluminescence and fluorescence analysis
Authors: Kazumura Kimiko , Takeuchi Kozo , Hatano Yukiko , Hara Akiko , Miwa Toshiyuki , Hattori Masaki , Kondo Fusanori , Morishita Naokazu , Tsuchiya Hiroshi , Osawa Toshihiko 
Published: July 2021

AbstractThe previous slide-glass type system could simultaneously detect reactive and highly reactive oxygen species, i.e., superoxide radicals (O2−·) and hypochlorite ions (OCl−) elicited from leucocytes in sample blood, but had some drawbacks, i.e., signal noise from air-flow stirring, potential biohazard risks, etc. because of open samples placed on a slide glass. We overcame these drawbacks by adopting a fluidic-chip container in a new system, which resulted in higher sensitivity and more stable measurements. Using the new system, we conducted a pilot study on nominally healthy volunteers to find whether or not the monitored activities of leukocytes can distinguish more or less unhealthy conditions from healthy ones. At first, healthy volunteers of both genders and of various ages showed that the fluctuation magnitudes (%) of O2−·and OCl−were nearly similar to each other and to that of the neutrophil count fluctuation. These parameters sometimes exceeded the healthy fluctuation range. By comparing these large fluctuations with the data of an inflammation marker C-reactive protein (CRP), the neutrophil count fluctuation and the timings/symptoms of abnormalities found in questionnaire, we could gain information suggesting the factors causing the large fluctuations. The new system could detect bodily abnormalities earlier than CRP or self-aware symptoms.
Strictly regulated agonist-dependent activation of AMPA-R is the key characteristic of TAK-653 for robust synaptic responses and cognitive improvement
Authors: Suzuki Atsushi , Kunugi Akiyoshi , Tajima Yasukazu , Suzuki Noriko , Suzuki Motohisa , Toyofuku Masashi , Kuno Haruhiko , Sogabe Satoshi , Kosugi Yohei , Awasaki Yasuyuki , Kaku Tomohiro , Kimura Haruhide 
Published: July 2021

AbstractAgonistic profiles of AMPA receptor (AMPA-R) potentiators may be associated with seizure risk and bell-shaped dose-response effects. Here, we report the pharmacological characteristics of a novel AMPA-R potentiator, TAK-653, which exhibits minimal agonistic properties. TAK-653 bound to the ligand binding domain of recombinant AMPA-R in a glutamate-dependent manner. TAK-653 strictly potentiated a glutamate-induced Ca2+ influx in hGluA1i-expressing CHO cells through structural interference at Ser743 in GluA1. In primary neurons, TAK-653 augmented AMPA-induced Ca2+ influx and AMPA-elicited currents via physiological AMPA-R with little agonistic effects. Interestingly, TAK-653 enhanced electrically evoked AMPA-R-mediated EPSPs more potently than AMPA (agonist) or LY451646 (AMPA-R potentiator with a prominent agonistic effect) in brain slices. Moreover, TAK-653 improved cognition for both working memory and recognition memory, while LY451646 did so only for recognition memory, and AMPA did not improve either. These data suggest that the facilitation of phasic AMPA-R activation by physiologically-released glutamate is the key to enhancing synaptic and cognitive functions, and nonselective activation of resting AMPA-Rs may negatively affect this process. Importantly, TAK-653 had a wide safety margin against convulsion; TAK-653 showed a 419-fold (plasma Cmax) and 1017-fold (AUC plasma) margin in rats. These findings provide insight into a therapeutically important aspect of AMPA-R potentiation.
Climate change may induce connectivity loss and mountaintop extinction in Central American forests
Authors: Baumbach Lukas , Warren Dan L. , Yousefpour Rasoul , Hanewinkel Marc 
Published: July 2021

AbstractThe tropical forests of Central America serve a pivotal role as biodiversity hotspots and provide ecosystem services securing human livelihood. However, climate change is expected to affect the species composition of forest ecosystems, lead to forest type transitions and trigger irrecoverable losses of habitat and biodiversity. Here, we investigate potential impacts of climate change on the environmental suitability of main plant functional types (PFTs) across Central America. Using a large database of occurrence records and physiological data, we classify tree species into trait-based groups and project their suitability under three representative concentration pathways (RCPs 2.6, 4.5 and 8.5) with an ensemble of state-of-the-art correlative modelling methods. Our results forecast transitions from wet towards generalist or dry forest PFTs for large parts of the study region. Moreover, suitable area for wet-adapted PFTs is projected to latitudinally diverge and lose connectivity, while expected upslope shifts of montane species point to high risks of mountaintop extinction. These findings underline the urgent need to safeguard the connectivity of habitats through biological corridors and extend protected areas in the identified transition hotspots.
An implantable human stem cell-derived tissue-engineered rostral migratory stream for directed neuronal replacement
Authors: O’Donnell John C. , Purvis Erin M. , Helm Kaila V. T. , Adewole Dayo O. , Zhang Qunzhou , Le Anh D. , Cullen D. Kacy 
Published: July 2021

AbstractThe rostral migratory stream (RMS) facilitates neuroblast migration from the subventricular zone to the olfactory bulb throughout adulthood. Brain lesions attract neuroblast migration out of the RMS, but resultant regeneration is insufficient. Increasing neuroblast migration into lesions has improved recovery in rodent studies. We previously developed techniques for fabricating an astrocyte-based Tissue-Engineered RMS (TE-RMS) intended to redirect endogenous neuroblasts into distal brain lesions for sustained neuronal replacement. Here, we demonstrate that astrocyte-like-cells can be derived from adult human gingiva mesenchymal stem cells and used for TE-RMS fabrication. We report that key proteins enriched in the RMS are enriched in TE-RMSs. Furthermore, the human TE-RMS facilitates directed migration of immature neurons in vitro. Finally, human TE-RMSs implanted in athymic rat brains redirect migration of neuroblasts out of the endogenous RMS. By emulating the brain’s most efficient means for directing neuroblast migration, the TE-RMS offers a promising new approach to neuroregenerative medicine.
Promouvoir et diffuser la culture scientifique
Authors:   Commission « Culture scientifique » de la Société Française de Physique
Published: July 2021

Partie intégrante de la Culture, la culture scientifique n’est pas toujours présente à l’esprit lorsque l’on parle de « culture générale ». Elle aussi pourtant s’acquiert, s’entretient et se diffuse au bénéfice des mêmes deux publics: les jeunes et les « citoyens » adultes.
Le texte qui suit a pour objet de souligner le rôle des acteurs chargés de la transmettre, intermédiaires nécessaires entre ces publics et les scientifiques « producteurs » de connaissances. Aux médiateurs et aux professionnels des sciences et techniques, de mettre en commun leurs compétences pour transmettre des savoirs sous des formes accessibles.
Konventionelle Bildgebung Fuß und Sprunggelenk – akut und chronisch
Authors: Schlickewei Carsten , Priemel Matthias , Frosch Karl-Heinz , Barg Alexej 
Published: July 2021

ZusammenfassungGrundlage für Diagnose und Behandlung akuter und chronischer Beschwerden an Fuß und Sprunggelenk sind, neben einer ausführlichen klinischen Untersuchung, konventionelle Röntgenbilder. Basis der Diagnostik sind standardisierte Röntgenaufnahmen, wobei empfohlen wird, bei der Wahl der Projektion zwischen akuten und chronischen Beschwerden zu differenzieren. Bei akuten Symptomen an Fuß und Sprunggelenk empfehlen wir standardmäßig eine „5er-Serie“ mit Röntgen des Fußes dorsoplantar, schräg und lateral sowie des Sprunggelenks anterior–posterior und lateral ohne Belastung. Bei chronischen Beschwerden hingegen empfiehlt sich eine „4er-Serie“ unter Belastung mit Röntgen des Fußes dorsoplantar und lateral sowie des Sprunggelenks anterior–posterior sowie einer Saltzman-Aufnahme. Wichtig ist es, bei chronischen Symptomen die Aufnahmen im Stehen und unter Belastung durchzuführen, während bei Patienten nach frischem Trauma oder unmittelbar nach einem operativen Eingriff
Röntgenaufnahmen ohne Belastung durchgeführt werden sollten. Nach primär konventioneller Bildgebung kann bei Bedarf die Diagnostik im Anschluss zielgerichtet erweitert werden.