bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental demonstration of continuous quantum error correction
Authors: Livingston William P. , Blok Machiel S. , Flurin Emmanuel , Dressel Justin , Jordan Andrew N. , Siddiqi Irfan 
Published: April 2022

AbstractThe storage and processing of quantum information are susceptible to external noise, resulting in computational errors. A powerful method to suppress these effects is quantum error correction. Typically, quantum error correction is executed in discrete rounds, using entangling gates and projective measurement on ancillary qubits to complete each round of error correction. Here we use direct parity measurements to implement a continuous quantum bit-flip correction code in a resource-efficient manner, eliminating entangling gates, ancillary qubits, and their associated errors. An FPGA controller actively corrects errors as they are detected, achieving an average bit-flip detection efficiency of up to 91%. Furthermore, the protocol increases the relaxation time of the protected logical qubit by a factor of 2.7 over the relaxation times of the bare comprising qubits. Our results showcase resource-efficient stabilizer measurements in a multi-qubit architecture and demonstrate how continuous error correction codes can address challenges in realizing a fault-tolerant system.
TGS1 mediates 2,2,7-trimethyl guanosine capping of the human telomerase RNA to direct telomerase dependent telomere maintenance
Authors: Buemi Valentina , Schillaci Odessa , Santorsola Mariangela , Bonazza Deborah , Broccia Pamela Veneziano , Zappone Annie , Bottin Cristina , Dell’Omo Giulia , Kengne Sylvie , Cacchione Stefano , Raffa Grazia Daniela , Piazza Silvano , di Fagagna Fabrizio d’Adda , Benetti Roberta , Cortale Maurizio , Zanconati Fabrizio , Del Sal Giannino , Schoeftner Stefan 
Published: April 2022

AbstractPathways that direct the selection of the telomerase-dependent or recombination-based, alternative lengthening of telomere (ALT) maintenance pathway in cancer cells are poorly understood. Using human lung cancer cells and tumor organoids we show that formation of the 2,2,7-trimethylguanosine (TMG) cap structure at the human telomerase RNA 5′ end by the Trimethylguanosine Synthase 1 (TGS1) is central for recruiting telomerase to telomeres and engaging Cajal bodies in telomere maintenance. TGS1 depletion or inhibition by the natural nucleoside sinefungin impairs telomerase recruitment to telomeres leading to Exonuclease 1 mediated generation of telomere 3′ end protrusions that engage in RAD51-dependent, homology directed recombination and the activation of key features of the ALT pathway. This indicates a critical role for 2,2,7-TMG capping of the RNA component of human telomerase (hTR) in enforcing telomerase-dependent telomere maintenance to restrict the formation of telomeric substrates conductive to ALT. Our work introduces a targetable pathway of telomere maintenance that holds relevance for telomere-related diseases such as cancer and aging.
Evolution of the murine gut resistome following broad-spectrum antibiotic treatment
Authors: de Nies Laura , Busi Susheel Bhanu , Tsenkova Mina , Halder Rashi , Letellier Elisabeth , Wilmes Paul 
Published: April 2022

AbstractThe emergence and spread of antimicrobial resistance (AMR) represent an ever-growing healthcare challenge worldwide. Nevertheless, the mechanisms and timescales shaping this resistome remain elusive. Using an antibiotic cocktail administered to a murine model along with a longitudinal sampling strategy, we identify the mechanisms by which gut commensals acquire antimicrobial resistance genes (ARGs) after a single antibiotic course. While most of the resident bacterial populations are depleted due to the treatment,Akkermansia muciniphilaand members of the Enterobacteriaceae, Enterococcaceae, and Lactobacillaceae families acquire resistance and remain recalcitrant. We identify specific genes conferring resistance against the antibiotics in the corresponding metagenome-assembled genomes (MAGs) and trace their origins within each genome. Here we show that, while mobile genetic elements (MGEs), including bacteriophages and plasmids, contribute to the spread of ARGs, integrons represent key factors mediating AMR in the antibiotic-treated mice. Our findings suggest that a single course of antibiotics alone may act as the selective sweep driving ARG acquisition and incidence in gut commensals over a single mammalian lifespan.
Two-photon-absorbing ruthenium complexes enable near infrared light-driven photocatalysis
Authors: Han Guanqun , Li Guodong , Huang Jie , Han Chuang , Turro Claudia , Sun Yujie 
Published: April 2022

AbstractOne-photon-absorbing photosensitizers are commonly used in homogeneous photocatalysis which require the absorption of ultraviolet (UV) /visible light to populate the desired excited states with adequate energy and lifetime. Nevertheless, the limited penetration depth and competing absorption by organic substrates of UV/visible light calls upon exploring the utilization of longer-wavelength irradiation, such as near-infrared light (λirr > 700 nm). Despite being found applications in photodynamic therapy and bioimaging, two-photon absorption (TPA), the simultaneous absorption of two photons by one molecule, has been rarely explored in homogeneous photocatalysis. Herein, we report a group of ruthenium polypyridyl complexes possessing TPA capability that can drive a variety of organic transformations upon irradiation with 740 nm light. We demonstrate that these TPA ruthenium complexes can operate in an analogous manner as one-photon-absorbing photosensitizers for both energy-transfer and photoredox reactions, as well as function in concert with a transition metal co-catalyst for metallaphotoredox C–C coupling reactions.
Ultrasensitive barocaloric material for room-temperature solid-state refrigeration
Authors: Ren Qingyong , Qi Ji , Yu Dehong , Zhang Zhe , Song Ruiqi , Song Wenli , Yuan Bao , Wang Tianhao , Ren Weijun , Zhang Zhidong , Tong Xin , Li Bing 
Published: April 2022

AbstractOne of the greatest obstacles to the real application of solid-state refrigeration is the huge driving fields. Here, we report a giant barocaloric effect in inorganic NH4I with reversible entropy changes of $$\Delta {S}_{{P}_{0}\to P}^{{{\max }}}$$
Δ

S

P

0

→
P

max

∼71 J K−1 kg−1 around room temperature, associated with a structural phase transition. The phase transition temperature, Tt, varies dramatically with pressure at a rate of dTt/dP ∼0.79 K MPa−1, which leads to a very small saturation driving pressure of ΔP ∼40 MPa, an extremely large barocaloric strength of $$\left|\Delta {S}_{{P}_{0}\to P}^{{{\max }}}/\Delta P\right|$$

Δ

S

P

0

→
P

max

/
Δ
P

∼1.78 J K−1 kg−1 MPa−1, as well as a broad temperature span of ∼41 K under 80 MPa. Comprehensive characterizations of the crystal structures and atomic dynamics by neutron scattering reveal that a strong reorientation-vibration coupling is responsible for the large pressure sensitivity of Tt. This work is expected to advance the practical application of barocaloric refrigeration.
Experimental evidence of tetrahedral symmetry breaking in SiO2 glass under pressure
Authors: Kono Yoshio , Ohara Koji , Kondo Nozomi M. , Yamada Hiroki , Hiroi Satoshi , Noritake Fumiya , Nitta Kiyofumi , Sekizawa Oki , Higo Yuji , Tange Yoshinori , Yumoto Hirokatsu , Koyama Takahisa , Yamazaki Hiroshi , Senba Yasunori , Ohashi Haruhiko , Goto Shunji , Inoue Ichiro , Hayashi Yujiro , Tamasaku Kenji , Osaka Taito , Yamada Jumpei , Yabashi Makina 
Published: April 2022

AbstractBimodal behavior in the translational order of silicon’s second shell in SiO2 liquid at high temperatures and high pressures has been recognized in theoretical studies, and the fraction of the S state with high tetrahedrality is considered as structural origin of the anomalous properties. However, it has not been well identified in experiment. Here we show experimental evidence of a bimodal behavior in the translational order of silicon’s second shell in SiO2 glass under pressure. SiO2 glass shows tetrahedral symmetry structure with separation between the first and second shells of silicon at low pressures, which corresponds to the S state structure reported in SiO2 liquid. On the other hand, at high pressures, the silicon’s second shell collapses onto the first shell, and more silicon atoms locate in the first shell. These observations indicate breaking of local tetrahedral symmetry in SiO2 glass under pressure, as well as SiO2 liquid.
Evanescent scattering imaging of single protein binding kinetics and DNA conformation changes
Authors: Zhang Pengfei , Zhou Lei , Wang Rui , Zhou Xinyu , Jiang Jiapei , Wan Zijian , Wang Shaopeng 
Published: April 2022

AbstractEvanescent illumination has been widely used to detect single biological macromolecules because it can notably enhance light-analyte interaction. However, the current evanescent single-molecule detection system usually requires specially designed microspheres or nanomaterials. Here we show that single protein detection and imaging can be realized on a plain glass surface by imaging the interference between the evanescent lights scattered by the single proteins and by the natural roughness of the cover glass. This allows us to quantify the sizes of single proteins, characterize the protein–antibody interactions at the single-molecule level, and analyze the heterogeneity of single protein binding behaviors. In addition, owing to the exponential distribution of evanescent field intensity, the evanescent imaging system can track the analyte axial movement with high resolution, which can be used to analyze the DNA conformation changes, providing one solution for detecting small molecules, such as microRNA. This work demonstrates a label-free single protein imaging method with ordinary consumables and may pave a road for detecting small biological molecules.
Structural insights into TRPV2 activation by small molecules
Authors: Pumroy Ruth A. , Protopopova Anna D. , Fricke Tabea C. , Lange Iris U. , Haug Ferdinand M. , Nguyen Phuong T. , Gallo Pamela N. , Sousa Bárbara B. , Bernardes Gonçalo J. L. , Yarov-Yarovoy Vladimir , Leffler Andreas , Moiseenkova-Bell Vera Y. 
Published: April 2022

AbstractTransient receptor potential vanilloid 2 (TRPV2) is involved in many critical physiological and pathophysiological processes, making it a promising drug target. Here we present cryo-electron microscopy (cryo-EM) structures of rat TRPV2 in lipid nanodiscs activated by 2-aminoethoxydiphenyl borate (2-APB) and propose a TRPV2-specific 2-ABP binding site at the interface of S5 of one monomer and the S4-S5 linker of the adjacent monomer. In silico docking and electrophysiological studies confirm the key role of His521 and Arg539 in 2-APB activation of TRPV2. Additionally, electrophysiological experiments show that the combination of 2-APB and cannabidiol has a synergetic effect on TRPV2 activation, and cryo-EM structures demonstrate that both drugs were able to bind simultaneously. Together, our cryo-EM structures represent multiple functional states of the channel, providing a native picture of TRPV2 activation by small molecules and a structural framework for the development of TRPV2-specific activators.
Microscopic theory of exciton and trion polaritons in doped monolayers of transition metal dichalcogenides
Authors: Zhumagulov Yaroslav Vladimirovich , Chiavazzo Salvatore , Gulevich Dmitry Romanovich , Perebeinos Vasili , Shelykh Ivan Andreevich , Kyriienko Oleksandr 
Published: April 2022

AbstractWe study a doped transition metal dichalcogenide (TMDC) monolayer in an optical microcavity. Using the microscopic theory, we simulate spectra of quasiparticles emerging due to the interaction of material excitations and a high-finesse optical mode, providing a comprehensive analysis of optical spectra as a function of Fermi energy and predicting several modes in the strong light-matter coupling regime. In addition to exciton-polaritons and trion-polaritons, we report polaritonic modes that become bright due to the interaction of excitons with free carriers. At large doping, we reveal strongly coupled modes corresponding to excited trions that hybridize with a cavity mode. We also demonstrate that the increase of carrier concentration can change the nature of the system’s ground state from the dark to the bright one. Our results offer a unified description of polaritonic modes in a wide range of free electron densities.
Degenerate plaquette physics as key ingredient of high-temperature superconductivity in cuprates
Authors: Danilov Michael , van Loon Erik G. C. P. , Brener Sergey , Iskakov Sergei , Katsnelson Mikhail I. , Lichtenstein Alexander I. 
Published: April 2022

AbstractWe study the physics of high-temperature cuprate superconductors starting from the highly degenerate four-site plaquette of the $$t-t^{\prime} -U$$

t
−

t

′

−
U

Hubbard model as a reference system. The degeneracy causes strong fluctuations when a lattice of plaquettes is constructed. We show that there is a large binding energy between holes when a set of four plaquettes is considered. The next-nearest-neighbour hopping $$t^{\prime}$$

t

′

plays a crucial role in the formation of these strongly bound electronic bipolarons whose coherence at lower temperature could be the explanation for superconductivity. A complementary approach is cluster dual fermion starting from a single degenerate plaquette, which contains the relevant short-ranged fluctuations from the beginning. It gives d-wave superconductivity as the leading instability under a reasonably broad range of parameters. The origin of the pseudogap is also discussed in terms of the coupling of degenerate plaquettes. Thus, some of the essential elements of cuprate superconductivity appear from the local plaquette physics.
SARS-CoV-2-specific T-cell epitope repertoire in convalescent and mRNA-vaccinated individuals
Authors: Lang-Meli Julia , Luxenburger Hendrik , Wild Katharina , Karl Vivien , Oberhardt Valerie , Salimi Alizei Elahe , Graeser Anne , Reinscheid Matthias , Roehlen Natascha , Reeg David B. , Giese Sebastian , Ciminski Kevin , Götz Veronika , August Dietrich , Rieg Siegbert , Waller Cornelius F. , Wengenmayer Tobias , Staudacher Dawid , Huzly Daniela , Bengsch Bertram , Kochs Georg , Schwemmle Martin , Emmerich Florian , Boettler Tobias , Thimme Robert , Hofmann Maike , Neumann-Haefelin Christoph 
Published: April 2022

AbstractContinuously emerging variants of concern (VOCs) sustain the SARS-CoV-2 pandemic. The SARS-CoV-2 Omicron/B.1.1.529 VOC harbours multiple mutations in the spike protein associated with high infectivity and efficient evasion from humoral immunity induced by previous infection or vaccination. By performing in-depth comparisons of the SARS-CoV-2-specific T-cell epitope repertoire after infection and messenger RNA vaccination, we demonstrate that spike-derived epitopes were not dominantly targeted in convalescent individuals compared to non-spike epitopes. In vaccinees, however, we detected a broader spike-specific T-cell response compared to convalescent individuals. Booster vaccination increased the breadth of the spike-specific T-cell response in convalescent individuals but not in vaccinees with complete initial vaccination. In convalescent individuals and vaccinees, the targeted T-cell epitopes were broadly conserved between wild-type SARS-CoV-2 variant B and Omicron/B.1.1.529. Hence, our data emphasize the relevance of vaccine-induced spike-specific CD8+ T-cell responses in combating VOCs including Omicron/B.1.1.529 and support the benefit of boosting convalescent individuals with mRNA vaccines.
Exocomets size distribution in the $$\beta$$ Pictoris planetary system
Authors: Lecavelier des Etangs Alain , Cros Lucie , Hébrard Guillaume , Martioli Eder , Duquesnoy Marc , Kenworthy Matthew A. , Kiefer Flavien , Lacour Sylvestre , Lagrange Anne-Marie , Meunier Nadège , Vidal-Madjar Alfred 
Published: April 2022

AbstractThe star $$\beta$$
β
Pictoris harbors a young planetary system of about 20 million years old, which is characterized by the presence of a gaseous and dusty debris disk, at least two massive planets and many minor bodies. For more than thirty years, exocomets transiting the star have been detected using spectroscopy, probing the gaseous part of the cometary comas and tails. The detection of the dusty component of the tails can be performed through photometric observations of the transits. Since 2018, the Transiting Exoplanet Survey Satellite has observed $$\beta$$
β
Pic for a total of 156 days. Here we report an analysis of the TESS photometric data set with the identification of a total of 30 transits of exocomets. Our statistical analysis shows that the number of transiting exocomet events (N) as a function of the absorption depth (AD) in the light curve follows a power law in the form $$dN(AD) \propto AD^{-\alpha }$$

d
N

(
A
D
)

∝
A

D

-
α

, where $$\alpha =2.3\pm 0.4$$

α
=
2.3
±
0.4

. This distribution of absorption depth leads to a differential comet size distribution proportional to $$R^{-\gamma }$$

R

-
γ

, where $$\gamma =3.6 \pm 0.8$$

γ
=
3.6
±
0.8

, showing a striking similarity to the size distribution of comets in the Solar system and the distribution of a collisionally relaxed population ($$\gamma _{{\text{D}}}= 3.5$$

γ
D

=
3.5

).
Efficient dendritic learning as an alternative to synaptic plasticity hypothesis
Authors: Hodassman Shiri , Vardi Roni , Tugendhaft Yael , Goldental Amir , Kanter Ido 
Published: April 2022

AbstractSynaptic plasticity is a long-lasting core hypothesis of brain learning that suggests local adaptation between two connecting neurons and forms the foundation of machine learning. The main complexity of synaptic plasticity is that synapses and dendrites connect neurons in series and existing experiments cannot pinpoint the significant imprinted adaptation location. We showed efficient backpropagation and Hebbian learning on dendritic trees, inspired by experimental-based evidence, for sub-dendritic adaptation and its nonlinear amplification. It has proven to achieve success rates approaching unity for handwritten digits recognition, indicating realization of deep learning even by a single dendrite or neuron. Additionally, dendritic amplification practically generates an exponential number of input crosses, higher-order interactions, with the number of inputs, which enhance success rates. However, direct implementation of a large number of the cross weights and their exhaustive manipulation independently is beyond existing and anticipated computational power. Hence, a new type of nonlinear adaptive dendritic hardware for imitating dendritic learning and estimating the computational capability of the brain must be built.
Dynamics of quantum droplets in an external harmonic confinement
Authors: Pathak Maitri R. , Nath Ajay 
Published: April 2022

AbstractRecent theoretical and experimental results show that one-dimensional (1D) weakly interacting atomic Bose-Bose mixtures with repulsive interspecies mean field (MF) interaction are stabilized by attractive quadratic beyond-mean-field (BMF) effects into self-bound quantum droplet (QD) in free space. Here, we construct an exact analytical model to investigate the structure and dynamics of QDs in presence of external harmonic confinement by solving the 1D extended Gross–Pitäevskii equation (eGPE) with temporal variation of MF and BMF interactions. The model provides the analytical form of wavefunction, phase, MF and BMF nonlinearities. The generation of QDs and interesting droplet to soliton transition in presence of regular/expulsive parabolic traps by taking the comparable MF and BMF interactions are illustrated. We derive the phase diagram of the droplet-soliton phase transition between amplitude of MF, BMF interactions and harmonic oscillator frequency. The strength and form of oscillator frequency are identified as key parameter for tuning the compression, fragmentation and transport of droplets. Finally, the stability of the obtained solutions are confirmed from Vakhitov–Kolokolov (VK) criterion and are found stable.
Sustainable human population density in Western Europe between 560.000 and 360.000 years ago
Authors: Rodríguez Jesús , Willmes Christian , Sommer Christian , Mateos Ana 
Published: April 2022

AbstractThe time period between 560 and 360 ka (MIS14 to MIS11) was critical for the evolution of the Neanderthal lineage and the appearance of Levallois technology in Europe. The shifts in the distribution of the human populations, driven by cyclical climate changes, are generally accepted to have played major roles in both processes. We used a dataset of palaeoclimate maps and a species distribution model to reconstruct the changes in the area of Western Europe with suitable environmental conditions for humans during 11 time intervals of the MIS14 to MIS 11 period. Eventually, the maximum sustainable human population within the suitable area during each time interval was estimated by extrapolating the relationship observed between recent hunter-gatherer population density and net primary productivity and applying it to the past. Contrary to common assumptions, our results showed the three Mediterranean Peninsulas were not the only region suitable for humans during the glacial periods. The estimated total sustainable population of Western Europe from MIS14 to MIS11 oscillated between 13,000 and 25,000 individuals. These results offer a new theoretical scenario to develop models and hypotheses to explain cultural and biological evolution during the Middle Pleistocene in Western Europe.
Effective mathematical modelling of health passes during a pandemic
Authors: Hohenegger Stefan , Cacciapaglia Giacomo , Sannino Francesco 
Published: April 2022

AbstractWe study the impact on the epidemiological dynamics of a class of restrictive measures that are aimed at reducing the number of contacts of individuals who have a higher risk of being infected with a transmittable disease. Such measures are currently either implemented or at least discussed in numerous countries worldwide to ward off a potential new wave of COVID-19. They come in the form of Health Passes (HP), which grant full access to public life only to individuals with a certificate that proves that they have either been fully vaccinated, have recovered from a previous infection or have recently tested negative to SARS-Cov-2. We develop both a compartmental model as well as an epidemic Renormalisation Group approach, which is capable of describing the dynamics over a longer period of time, notably an entire epidemiological wave. Introducing different versions of HPs in this model, we are capable of providing quantitative estimates on the effectiveness of the underlying measures as a function of the fraction of the population that is vaccinated and the vaccination rate. We apply our models to the latest COVID-19 wave in several European countries, notably Germany and Austria, which validate our theoretical findings.