bluuebunny/crossref_metadata_2025 huggingface dataset:
Topological phase singularities in atomically thin high-refractive-index materials
Authors: Ermolaev Georgy , Voronin Kirill , Baranov Denis G. , Kravets Vasyl , Tselikov Gleb , Stebunov Yury , Yakubovsky Dmitry , Novikov Sergey , Vyshnevyy Andrey , Mazitov Arslan , Kruglov Ivan , Zhukov Sergey , Romanov Roman , Markeev Andrey M. , Arsenin Aleksey , Novoselov Kostya S. , Grigorenko Alexander N. , Volkov Valentyn
Published: April 2022

Atomically thin transition metal dichalcogenides (TMDCs) present a promising platform for numerous photonic applications due to excitonic spectral features, possibility to tune their constants by external gating, doping, or light, and mechanical stability. Utilization of such materials for sensing or optical modulation purposes would require a clever optical design, as by itself the 2D materials can offer only a small optical phase delay – consequence of the atomic thickness. To address this issue, we combine films of 2D semiconductors which exhibit excitonic lines with the Fabry-Perot resonators of the standard commercial SiO2/Si substrate, in order to realize topological phase singularities in reflection. Around these singularities, reflection spectra demonstrate rapid phase changes while the structure behaves as a perfect absorber. Furthermore, we demonstrate that such topological phase singularities are ubiquitous for the entire class of atomically thin TMDCs and other high-refractive-index materials, making it a powerful tool for phase engineering in flat optics. As a practical demonstration, we employ PdSe2 topological phase singularities for a refractive index sensor and demonstrate its superior phase sensitivity compared to typical surface plasmon resonance sensors.
Human serum triggers antibiotic tolerance in Staphylococcus aureus
Authors: Ledger Elizabeth V. K. , Mesnage Stéphane , Edwards Andrew M.
Published: April 2022

Staphylococcus aureus frequently causes infections that are challenging to treat, leading to high rates of persistent and relapsing infection. Here, to understand how the host environment influences treatment outcomes, we study the impact of human serum on staphylococcal antibiotic susceptibility. We show that serum triggers a high degree of tolerance to the lipopeptide antibiotic daptomycin and several other classes of antibiotic. Serum-induced daptomycin tolerance is due to two independent mechanisms. Firstly, the host defence peptide LL-37 induces tolerance by triggering the staphylococcal GraRS two-component system, leading to increased peptidoglycan accumulation. Secondly, GraRS-independent increases in membrane cardiolipin abundance are required for full tolerance. When both mechanisms are blocked, S. aureus incubated in serum is as susceptible to daptomycin as when grown in laboratory media. Our work demonstrates that host factors can significantly modulate antibiotic susceptibility via diverse mechanisms, and combination therapy may provide a way to mitigate this.
Full 2π tunable phase modulation using avoided crossing of resonances
Authors: Kim Ju Young , Park Juho , Holdman Gregory R. , Heiden Jacob T. , Kim Shinho , Brar Victor W. , Jang Min Seok
Published: April 2022

Active metasurfaces have been proposed as one attractive means of achieving high-resolution spatiotemporal control of optical wavefronts, having applications such as LIDAR and dynamic holography. However, achieving full, dynamic phase control has been elusive in metasurfaces. In this paper, we unveil an electrically tunable metasurface design strategy that operates near the avoided crossing of two resonances, one a spectrally narrow, over-coupled resonance and the other with a high resonance frequency tunability. This strategy displays an unprecedented upper limit of 4π range of dynamic phase modulation with no significant variations in optical amplitude, by enhancing the phase tunability through utilizing two coupled resonances. A proof-of-concept metasurface is justified analytically and verified numerically in an experimentally accessible platform using quasi-bound states in the continuum and graphene plasmon resonances, with results showing a 3π phase modulation capacity with a uniform reflection amplitude of ~0.65.
Room temperature all-solid-state lithium batteries based on a soluble organic cage ionic conductor
Authors: Li Jing , Qi Jizhen , Jin Feng , Zhang Fengrui , Zheng Lei , Tang Lingfei , Huang Rong , Xu Jingjing , Chen Hongwei , Liu Ming , Qiu Yejun , Cooper Andrew I. , Shen Yanbin , Chen Liwei
Published: April 2022

All solid-state lithium batteries (SSLBs) are poised to have higher energy density and better safety than current liquid-based Li-ion batteries, but a central requirement is effective ionic conduction pathways throughout the entire cell. Here we develop a catholyte based on an emerging class of porous materials, porous organic cages (POCs). A key feature of these Li+ conducting POCs is their solution-processibility. They can be dissolved in a cathode slurry, which allows the fabrication of solid-state cathodes using the conventional slurry coating method. These Li+ conducting cages recrystallize and grow on the surface of the cathode particles during the coating process and are therefore dispersed uniformly in the slurry-coated cathodes to form a highly effective ion-conducting network. This catholyte is shown to be compatible with cathode active materials such as LiFePO4, LiCoO2 and LiNi0.5Co0.2Mn0.3O2, and results in SSLBs with decent electrochemical performance at room temperature.
Challenges and limits of mechanical stability in 3D direct laser writing
Authors: Sedghamiz Elaheh , Liu Modan , Wenzel Wolfgang
Published: April 2022

Direct laser writing is an effective technique for fabrication of complex 3D polymer networks using ultrashort laser pulses. Practically, it remains a challenge to design and fabricate high performance materials with different functions that possess a combination of high strength, substantial ductility, and tailored functionality, in particular for small feature sizes. To date, it is difficult to obtain a time-resolved microscopic picture of the printing process in operando. To close this gap, we herewith present a molecular dynamics simulation approach to model direct laser writing and investigate the effect of writing condition and aspect ratio on the mechanical properties of the printed polymer network. We show that writing conditions provide a possibility to tune the mechanical properties and an optimum writing condition can be applied to fabricate structures with improved mechanical properties. We reveal that beyond the writing parameters, aspect ratio plays an important role to tune the stiffness of the printed structures.
Engineering a passivating electric double layer for high performance lithium metal batteries
Authors: Zhang Weili , Lu Yang , Wan Lei , Zhou Pan , Xia Yingchun , Yan Shuaishuai , Chen Xiaoxia , Zhou Hangyu , Dong Hao , Liu Kai
Published: April 2022

In electrochemical devices, such as batteries, traditional electric double layer (EDL) theory holds that cations in the cathode/electrolyte interface will be repelled during charging, leaving a large amount of free solvents. This promotes the continuous anodic decomposition of the electrolyte, leading to a limited operation voltage and cycle life of the devices. In this work, we design a new EDL structure with adaptive and passivating properties. It is enabled by adding functional anionic additives in the electrolyte, which can selectively bind with cations and free solvents, forming unique cation-rich and branch-chain like supramolecular polymer structures with high electrochemical stability in the EDL inner layer. Due to this design, the anodic decomposition of ether-based electrolytes is significantly suppressed in the high voltage cathodes and the battery shows outstanding performances such as super-fast charging/discharging and ultra-low temperature applications, which is extremely hard in conventional electrolyte design principle. This unconventional EDL structure breaks the inherent perception of the classical EDL rearrangement mechanism and greatly improve electrochemical performances of the device.
Argyrodite-type advanced lithium conductors and transport mechanisms beyond paddle-wheel effect
Authors: Fang Hong , Jena Puru
Published: April 2022

Development of next-generation solid-state Li-ion batteries requires not only electrolytes with high room-temperature (RT) ionic conductivities but also a fundamental understanding of the ionic transport in solids. In spite of considerable work, only a few lithium conductors are known with the highest RT ionic conductivities ~ 0.01 S/cm and the lowest activation energies ~0.2 eV. New design strategy and novel ionic conduction mechanism are needed to expand the pool of high-performance lithium conductors as well as achieve even higher RT ionic conductivities. Here, we theoretically show that lithium conductors with RT ionic conductivity over 0.1 S/cm and low activation energies ~ 0.1 eV can be achieved by incorporating cluster-dynamics into an argyrodite structure. The extraordinary superionic metrics are supported by conduction mechanism characterized as a relay between local and long-range ionic diffusions, as well as correlational dynamics beyond the paddle-wheel effect.
Scalable production of ultrafine polyaniline fibres for tactile organic electrochemical transistors
Authors: Fang Bo , Yan Jianmin , Chang Dan , Piao Jinli , Ma Kit Ming , Gu Qiao , Gao Ping , Chai Yang , Tao Xiaoming
Published: April 2022

The development of continuous conducting polymer fibres is essential for applications ranging from advanced fibrous devices to frontier fabric electronics. The use of continuous conducting polymer fibres requires a small diameter to maximize their electroactive surface, microstructural orientation, and mechanical strength. However, regularly used wet spinning techniques have rarely achieved this goal due primarily to the insufficient slenderization of rapidly solidified conducting polymer molecules in poor solvents. Here we report a good solvent exchange strategy to wet spin the ultrafine polyaniline fibres. The slow diffusion between good solvents distinctly decreases the viscosity of protofibers, which undergo an impressive drawing ratio. The continuously collected polyaniline fibres have a previously unattained diameter below 5 µm, high energy and charge storage capacities, and favorable mechanical performance. We demonstrated an ultrathin all-solid organic electrochemical transistor based on ultrafine polyaniline fibres, which operated as a tactile sensor detecting pressure and friction forces at different levels.
Fast encirclement of an exceptional point for highly efficient and compact chiral mode converters
Authors: Shu Xiaoqian , Li Aodong , Hu Guangwei , Wang Jian , Alù Andrea , Chen Lin
Published: April 2022

Exceptional points (EPs) are degeneracies at which two or more eigenvalues and eigenstates of a physical system coalesce. Dynamically encircling EPs by varying the parameters of a non-Hermitian system enables chiral mode switching, that is, the final state of the system upon a closed loop in parameter space depends on the encircling handedness. In conventional schemes, the parametric evolution during the encircling process has to be sufficiently slow to ensure adiabaticity. Here, we show that fast parametric evolution along the parameter space boundary of the system Hamiltonian can relax this constraint. The proposed scheme enables highly efficient transmission and more compact footprint for asymmetric mode converters. We experimentally demonstrate these principles in a 57 μm-long double-coupled silicon waveguide system, enabling chiral mode switching with near-unity transmission efficiency at 1550 nm. This demonstration paves the way towards high-efficiency and highly integrated chiral mode switching for a wide range of practical applications.
Low energy carbon capture via electrochemically induced pH swing with electrochemical rebalancing
Authors: Jin Shijian , Wu Min , Jing Yan , Gordon Roy G. , Aziz Michael J.
Published: April 2022

We demonstrate a carbon capture system based on pH swing cycles driven through proton-coupled electron transfer of sodium (3,3′-(phenazine-2,3-diylbis(oxy))bis(propane-1-sulfonate)) (DSPZ) molecules. Electrochemical reduction of DSPZ causes an increase of hydroxide concentration, which absorbs CO2; subsequent electrochemical oxidation of the reduced DSPZ consumes the hydroxide, causing CO2outgassing. The measured electrical work of separating CO2from a binary mixture with N2, at CO2inlet partial pressures ranging from 0.1 to 0.5 bar, and releasing to a pure CO2exit stream at 1.0 bar, was measured for electrical current densities of 20–150 mA cm−2. The work for separating CO2from a 0.1 bar inlet and concentrating into a 1 bar exit is 61.3 kJ molCO2−1at a current density of 20 mA cm−2. Depending on the initial composition of the electrolyte, the molar cycle work for capture from 0.4 mbar extrapolates to 121–237 kJ molCO2−1at 20 mA cm−2. We also introduce an electrochemical rebalancing method that extends cell lifetime by recovering the initial electrolyte composition after it is perturbed by side reactions. We discuss the implications of these results for future low-energy electrochemical carbon capture devices.
Information normally considered task-irrelevant drives decision-making and affects premotor circuit recruitment
Authors: Schreiner Drew C. , Cazares Christian , Renteria Rafael , Gremel Christina M.
Published: April 2022

Decision-making is a continuous and dynamic process with prior experience reflected in and used by the brain to guide adaptive behavior. However, most neurobiological studies constrain behavior and/or analyses to task-related variables, not accounting for the continuous internal and temporal space in which they occur. We show mice rely on information learned through recent and longer-term experience beyond just prior actions and reward - including checking behavior and the passage of time - to guide self-initiated, self-paced, and self-generated actions. These experiences are represented in secondary motor cortex (M2) activity and its projections into dorsal medial striatum (DMS). M2 integrates this information to bias strategy-level decision-making, and DMS projections reflect specific aspects of this recent experience to guide actions. This suggests diverse aspects of experience drive decision-making and its neural representation, and shows premotor corticostriatal circuits are crucial for using selective aspects of experiential information to guide adaptive behavior.
Sea ice–air interactions amplify multidecadal variability in the North Atlantic and Arctic region
Authors: Deng Jiechun , Dai Aiguo
Published: April 2022

Winter surface air temperature (Tas) over the Barents–Kara Seas (BKS) and other Arctic regions has experienced rapid warming since the late 1990s that has been linked to the concurring cooling over Eurasia, and these multidecadal trends are attributed partly to internal variability. However, how such variability is generated is unclear. Through analyses of observations and model simulations, we show that sea ice–air two-way interactions amplify multidecadal variability in sea-ice cover, sea surface temperatures (SST) and Tas from the North Atlantic to BKS, and the Atlantic Meridional Overturning Circulation (AMOC) mainly through variations in surface fluxes. When sea ice is fixed in flux calculations, multidecadal variations are reduced substantially (by 20–50%) not only in Arctic Tas, but also in North Atlantic SST and AMOC. The results suggest that sea ice–air interactions are crucial for multidecadal climate variability in both the Arctic and North Atlantic, similar to air-sea interactions for tropical climate.
Structural transformation and catalytic hydrogenation activity of amidinate-protected copper hydride clusters
Authors: Liu Chun-Yu , Yuan Shang-Fu , Wang Song , Guan Zong-Jie , Jiang De-en , Wang Quan-Ming
Published: April 2022

Copper hydrides are important hydrogenation catalysts, but their poor stability hinders the practical applications. Ligand engineering is an effective strategy to tackle this issue. An amidinate ligand, N,N′-Di(5-trifluoromethyl-2-pyridyl)formamidinate (Tf-dpf) with four N-donors has been applied as a protecting agent in the synthesis of stable copper hydride clusters: Cu11H3(Tf-dpf)6(OAc)2 (Cu11) with three interfacial μ5-H and [Cu12H3(Tf-dpf)6(OAc)2]·OAc (Cu12) with three interstitial μ6-H. A solvent-triggered reversible interconversion between Cu11 and Cu12 has been observed thanks to the flexibility of Tf-dpf. Cu11 shows high activity in the reduction of 4-nitrophenol to 4-aminophenol, while Cu12 displays very low activity. Deuteration experiments prove that the type of hydride is the key in dictating the catalytic activity, for the interfacial μ5-H species in Cu11 are involved in the catalytic cycle whereas the interstitial μ6-H species in Cu12 are not. This work highlights the role of hydrides with regard to catalytic hydrogenation activity.
Deep insights into the gut microbial community of extreme longevity in south Chinese centenarians by ultra-deep metagenomics and large-scale culturomics
Authors: Li Congyong , Luan Zhe , Zhao Yiming , Chen Jun , Yang Yanan , Wang Cong , Jing Yujia , Qi Shirui , Li Zhuanyu , Guo Hao , Xu Wenyi , Zhao Bowen , Wu Chongming , Wang Shufang , Yang Yunsheng , Sun Gang
Published: April 2022

The gut microbes play important roles in human longevity and the gut microbiota profile of centenarians shows some unique features from young adults. Nowadays, most microbial studies on longevity are commonly based on metagenomic sequencing which may lose information about the functional microbes with extremely low abundance. Here, we combined in-depth metagenomic sequencing and large-scale culturomics to reveal the unique gut microbial structure of a Chinese longevity population, and to explore the possible relationship between intestinal microbes and longevity. Twenty-five healthy Hainan natives were enrolled in the study, including 12 centenarians and 13 senior neighbors. An average of 51.1 Gb raw sequencing data were obtained from individual fecal sample. We assembled 1778 non-redundant metagenomic assembled genomes (MAGs), 33.46% of which cannot be classified into known species. Comparison with the ordinary people in Hainan province, the longevous cohort displayed significantly decreased abundance of butyrate-producing bacteria and largely increased proportion of Escherichia coli, Desulfovibrio piger and Methanobrevibacter smithii. These species showed a constant change with aging. We also isolated 8,030 strains from these samples by large-scale culturomics, most of which belonged to 203 known species as identified by MALDI-TOF. Surprisingly, only 42.17% of the isolated species were also detected by metagenomics, indicating obvious complementarity between these two approaches. Combination of two complement methods, in-depth metagenomic sequencing and culturomics, provides deeper insights into the longevity-related gut microbiota. The uniquely enriched gut microbes in Hainan extreme decades population may help to promote health and longevity.
Identification and characterization of novel endolysins targeting Gardnerella vaginalis biofilms to treat bacterial vaginosis
Authors: Arroyo-Moreno Sara , Cummings Matthew , Corcoran David B. , Coffey Aidan , McCarthy Ronan R.
Published: April 2022

Bacterial vaginosis (BV) is a recurrent dysbiosis that is frequently associated with preterm birth, increased risk for acquisition of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). The overgrowth of a key pathobiont, Gardnerella vaginalis, as a recalcitrant biofilm is central to the development of this dysbiosis. Overgrowth of vaginal biofilms, seeded by initial G. vaginalis colonization, leads to recurrent symptomatic BV which is poorly resolved by classically used antibiotics. In this light, the use of bacteriophages and/or their proteins, represents a promising alternative. Here we identify 84 diverse anti-Gardnerella endolysins across 7 protein families. A subset of 36 endolysin candidates were refactored and overexpressed in an E. coli BL21 (DE3) system and 5 biochemically and structurally diverse endolysins were fully characterized. Each candidate endolysin showed good lytic activity against planktonic G. vaginalis ATCC14018, as well as G. vaginalis clinical isolates. These endolysin candidates were assayed in biofilm prevention and disruption assays, with biofilm disruption at low microgram concentrations (5 μg/ml) observed. In addition to clonal G. vaginalis biofilms, endolysin candidates could also successfully disrupt polyspecies biofilms. Importantly, none of our candidates showed lytic activity against commensal lactobacilli present in the vaginal microbiota such as L. crispatus, L. jensenii, L. gasseri, and L. iners or against Atopobium vaginae (currently classified as Fannyhessa vaginae). The potency and selectivity of these novel endolysins constitute a promising alternative treatment to combat BV, avoiding problems associated with antibiotic resistance, while retaining beneficial commensal bacteria in the vaginal flora. The diverse library of candidates reported here represents a strong repository of endolysins for further preclinical development.
Toward therapeutic electrophysiology: beta-band suppression as a biomarker in chronic local field potential recordings
Authors: Feldmann Lucia K. , Lofredi Roxanne , Neumann Wolf-Julian , Al-Fatly Bassam , Roediger Jan , Bahners Bahne H. , Nikolov Petyo , Denison Timothy , Saryyeva Assel , Krauss Joachim K. , Faust Katharina , Florin Esther , Schnitzler Alfons , Schneider Gerd-Helge , Kühn Andrea A.
Published: April 2022

Adaptive deep brain stimulation (aDBS) is a promising concept for feedback-based neurostimulation, with the potential of clinical implementation with the sensing-enabled Percept neurostimulator. We aim to characterize chronic electrophysiological activity during stimulation and to validate beta-band activity as a biomarker for bradykinesia. Subthalamic activity was recorded during stepwise stimulation amplitude increase OFF medication in 10 Parkinson’s patients during rest and finger tapping. Offline analysis of wavelet-transformed beta-band activity and assessment of inter-variable relationships in linear mixed effects models were implemented. There was a stepwise suppression of low-beta activity with increasing stimulation intensity (p = 0.002). Low-beta power was negatively correlated with movement speed and predictive for velocity improvements (p < 0.001), stimulation amplitude for beta suppression (p < 0.001). Here, we characterize beta-band modulation as a chronic biomarker for motor performance. Our investigations support the use of electrophysiology in therapy optimization, providing evidence for the use of biomarker analysis for clinical aDBS.
Electrophysiological dataset from macaque visual cortical area MST in response to a novel motion stimulus
Authors: Wild Benedict , Maamoun Amr , Mayr Yifan , Brockhausen Ralf , Treue Stefan
Published: April 2022

Establishing the cortical neural representation of visual stimuli is a central challenge of systems neuroscience. Publicly available data would allow a broad range of scientific analyses and hypothesis testing, but are rare and largely focused on the early visual system. To address the shortage of open data from higher visual areas, we provide a comprehensive dataset from a neurophysiology study in macaque monkey visual cortex that includes a complete record of extracellular action potential recordings from the extrastriate medial superior temporal (MST) area, behavioral data, and detailed stimulus records. It includes spiking activity of 172 single neurons recorded in 139 sessions from 4 hemispheres of 3 rhesus macaque monkeys. The data was collected across 3 experiments, designed to characterize the response properties of MST neurons to complex motion stimuli. This data can be used to elucidate visual information processing at the level of single neurons in a high-level area of primate visual cortex. Providing open access to this dataset also promotes the 3R-principle of responsible animal research.
OSASUD: A dataset of stroke unit recordings for the detection of Obstructive Sleep Apnea Syndrome
Authors: Bernardini Andrea , Brunello Andrea , Gigli Gian Luigi , Montanari Angelo , Saccomanno Nicola
Published: April 2022

Polysomnography (PSG) is a fundamental diagnostical method for the detection of Obstructive Sleep Apnea Syndrome (OSAS). Historically, trained physicians have been manually identifying OSAS episodes in individuals based on PSG recordings. Such a task is highly important for stroke patients, since in such cases OSAS is linked to higher mortality and worse neurological deficits. Unfortunately, the number of strokes per day vastly outnumbers the availability of polysomnographs and dedicated healthcare professionals. The data in this work pertains to 30 patients that were admitted to the stroke unit of the Udine University Hospital, Italy. Unlike previous studies, exclusion criteria are minimal. As a result, data are strongly affected by noise, and individuals may suffer from several comorbidities. Each patient instance is composed of overnight vital signs data deriving from multi-channel ECG, photoplethysmography and polysomnography, and related domain expert’s OSAS annotations. The dataset aims to support the development of automated methods for the detection of OSAS events based on just routinely monitored vital signs, and capable of working in a real-world scenario.
16S rRNA and metagenomic shotgun sequencing data revealed consistent patterns of gut microbiome signature in pediatric ulcerative colitis
Authors: Zuo Wenxuan , Wang Beibei , Bai Xin , Luan Yihui , Fan Yingying , Michail Sonia , Sun Fengzhu
Published: April 2022

Dysbiosis of human gut microbiota has been reported in association with ulcerative colitis (UC) in both children and adults using either 16S rRNA gene or shotgun sequencing data. However, these studies used either 16S rRNA or metagenomic shotgun sequencing but not both. We sequenced feces samples from 19 pediatric UC and 23 healthy children ages between 7 to 21 years using both 16S rRNA and metagenomic shotgun sequencing. The samples were analyzed using three different types of data: 16S rRNA genus level abundance, microbial species and pathway abundance profiles. We demonstrated that (a) the alpha diversity of pediatric UC cases is lower than that of healthy controls; (b) the beta diversity within children with UC is more variable than within the healthy children; (c) several microbial families includingAkkermansiaceae, Clostridiaceae, Eggerthellaceae,Lachnospiraceae, andOscillospiraceae, contain species that are depleted in pediatric UC compared to controls; (d) a few associated species unique to pediatric UC, but not adult UC, were also identified, e.g. some species in theChristensenellaceaefamily were found to be depleted and some species in theEnterobacteriaceaefamily were found to be enriched in pediatric UC; and (e) both 16S rRNA and shotgun sequencing data can predict pediatric UC status with area under the receiver operating characteristic curve (AUROC) of close to 0.90 based on cross validation. We showed that 16S rRNA data yielded similar results as shotgun data in terms of alpha diversity, beta diversity, and prediction accuracy. Our study demonstrated that pediatric UC subjects harbor a dysbiotic and less diverse gut microbial population with distinct differences from healthy children. We also showed that 16S rRNA data yielded accurate disease prediction results in comparison to shotgun data, which can be more expensive and laborious. These conclusions were confirmed in an independent data set of 7 pediatric UC cases and 8 controls.
Preferential stimulation of melanocytes by M2 macrophages to produce melanin through vascular endothelial growth factor
Authors: Han Heeju , Kim Yena , Mo Hyunkyung , Choi Si Hwa , Lee Kijun , Rim Yeri Alice , Ju Ji Hyeon
Published: April 2022

Post-inflammatory hyperpigmentation is a skin discoloration process that occurs following an inflammatory response or wound. As the skin begins to heal, macrophages first exhibit a proinflammatory phenotype (M1) during the early stages of tissue repair and then transition to a pro-healing, anti-inflammatory phenotype (M2) in later stages. During this process, M1 macrophages remove invading bacteria and M2 macrophages remodel surrounding tissue; however, the relationship between macrophages and pigmentation is unclear. In this study, we examined the effect of macrophages on melanin pigmentation using human induced pluripotent stem cells. Functional melanocytes were differentiated from human induced pluripotent stem cells and named as hiMels. The generated hiMels were then individually cocultured with M1 and M2 macrophages. Melanin synthesis decreased in hiMels cocultured with M1 macrophages but significantly increased in hiMels cocultured with M2 macrophages. Moreover, the expression of vascular endothelial growth factor was increased in M2 cocultured media. Our findings suggest that M2 macrophages, and not M1 macrophages, induce hyperpigmentation in scarred areas of the skin during tissue repair.
The structure of executive functions in preschool children and chimpanzees
Authors: Völter Christoph J. , Reindl Eva , Felsche Elisa , Civelek Zeynep , Whalen Andrew , Lugosi Zsuzsa , Duncan Lisa , Herrmann Esther , Call Josep , Seed Amanda M.
Published: April 2022

Executive functions (EF) are a core aspect of cognition. Research with adult humans has produced evidence for unity and diversity in the structure of EF. Studies with preschoolers favour a 1-factor model, in which variation in EF tasks is best explained by a single underlying trait on which all EF tasks load. How EF are structured in nonhuman primates remains unknown. This study starts to fill this gap through a comparative, multi-trait multi-method test battery with preschoolers (N = 185) and chimpanzees (N = 55). The battery aimed at measuring working memory updating, inhibition, and attention shifting with three non-verbal tasks per function. For both species the correlations between tasks were low to moderate and not confined to tasks within the same putative function. Factor analyses produced some evidence for the unity of executive functions in both groups, in that our analyses revealed shared variance. However, we could not conclusively distinguish between 1-, 2- or 3-factor models. We discuss the implications of our findings with respect to the ecological validity of current psychometric research.
Feces DNA analyses track the rehabilitation of a free-ranging beluga whale
Authors: Günther Babett , Jourdain Eve , Rubincam Lindsay , Karoliussen Richard , Cox Sam L. , Arnaud Haond Sophie
Published: April 2022

Following the sudden appearance, and subsequent efforts to support the survival of a beluga whale (Delphinapterus leucas) speculated to have been previously trained off the coast of Norway, we investigate the animal’s ability to readapt to life in the wild. Dietary DNA (dDNA) analysis was used to assess diet throughout this rehabilitation process, and during a return to unassisted foraging and self-feeding. Metabarcoding of feces collected throughout this process, confirmed the diversification of the beluga whale’s diet to local prey. These findings are indicative of improved foraging behavior, and the ability of this individual to resume wild foraging following a period of dependency in managed care. New insight of digestion rates, and the time window during which prey detection through dDNA analysis is appropriate was also obtained. Beyond the case study presented here, we demonstrate the power of dDNA analysis as a non-intrusive tool to assess the diet of large mammals and track progress adapting to life in the wild following release from captivity and rehabilitation programs.
Preventive aerobic training preserves sympathovagal function and improves DNA repair capacity of peripheral blood mononuclear cells in rats with cardiomyopathy
Authors: Ghignatti Paola Victória da Costa , Russo Mariana Kras Borges , Becker Tiago , Guecheva Temenouga Nikolova , Teixeira Luciele Varaschini , Lehnen Alexandre Machado , Schaun Maximiliano Isoppo , Leguisamo Natalia Motta
Published: April 2022

To evaluate the effect of preventive aerobic exercise training on sympathovagal function, cardiac function, and DNA repair capacity in a preclinical model of doxorubicin (DOX)-induced cardiomyopathy. Forty male Wistar-Kyoto rats were allocated into four groups (n = 10/group): D (DOX-treated) and C (controls) remained sedentary, and DT (DOX-trained) and CT (control-trained) performed aerobic training 4 days/week, during 4 weeks before exposure to DOX (4 mg/kg/week during 4 weeks) or saline solution. We evaluated cardiac function (echocardiography), hemodynamic and sympathovagal modulation (artery-femoral cannulation), cardiac troponin T levels, and DNA repair capacity (comet assay). Exercise training preserved ejection fraction (D: − 14.44% vs. DT: − 1.05%, p < 0.001), fractional shortening (D: − 8.96% vs. DT: − 0.27%, p = 0.025) and troponin T levels (D: 6.4 ± 3.6 vs. DT: 2.8 ± 1.7 ng/mL, p = 0.010). DOX increased heart rate variability (C: 27.7 ± 7.9 vs. D: 7.5 ± 2.2 ms2, p < 0.001) and induced sympathovagal dysfunction (LF/HF, C: 0.37 ± 0.15 vs. D: 0.15 ± 0.15, p = 0.036) through exacerbation of sympathetic function (LF, C: 0.22 ± 0.01 vs. D: 0.48 ± 0.24 Hz, p = 0.019). Peripheral mononuclear blood cells of DT animals presented lower residual DNA damage (D: 43.4 ± 8.4% vs. DT: 26 ± 3.4%, p = 0.003 after 1 h). Cardioprotective effects of preventive aerobic exercise training are mediated by preservation of sympathovagal function and improvement of DNA repair capacity of peripheral blood mononuclear cells.
A multi-parameter persistence framework for mathematical morphology
Authors: Chung Yu-Min , Day Sarah , Hu Chuan-Shen
Published: April 2022

The field of mathematical morphology offers well-studied techniques for image processing and is applicable for studies ranging from materials science to ecological pattern formation. In this work, we view morphological operations through the lens ofpersistent homology, a tool at the heart of the field of topological data analysis. We demonstrate that morphological operations naturally form a multiparameter filtration and that persistent homology can then be used to extract information about both topology and geometry in the images as well as to automate methods for optimizing the study and rendering of structure in images. For illustration, we develop an automated approach that utilizes this framework to denoise binary, grayscale, and color images with salt and pepper and larger spatial scale noise. We measure our example unsupervised denoising approach to state-of-the-art supervised, deep learning methods to show that our results are comparable.
First computational design using lambda-superstrings and in vivo validation of SARS-CoV-2 vaccine
Authors: Martínez Luis , Malaina Iker , Salcines-Cuevas David , Terán-Navarro Héctor , Zeoli Andrea , Alonso Santos , M. De la Fuente Ildefonso , Gonzalez-Lopez Elena , Ocejo-Vinyals J. Gonzalo , Gozalo-Margüello Mónica , Calvo-Montes Jorge , Alvarez-Dominguez Carmen
Published: April 2022

Coronavirus disease 2019 (COVID-19) is the greatest threat to global health at the present time, and considerable public and private effort is being devoted to fighting this recently emerged disease. Despite the undoubted advances in the development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, uncertainty remains about their future efficacy and the duration of the immunity induced. It is therefore prudent to continue designing and testing vaccines against this pathogen. In this article we computationally designed two candidate vaccines, one monopeptide and one multipeptide, using a technique involving optimizing lambda-superstrings, which was introduced and developed by our research group. We tested the monopeptide vaccine, thus establishing a proof of concept for the validity of the technique. We synthesized a peptide of 22 amino acids in length, corresponding to one of the candidate vaccines, and prepared a dendritic cell (DC) vaccine vector loaded with the 22 amino acids SARS-CoV-2 peptide (positions 50-71) contained in the NTD domain (DC-CoVPSA) of the Spike protein. Next, we tested the immunogenicity, the type of immune response elicited, and the cytokine profile induced by the vaccine, using a non-related bacterial peptide as negative control. Our results indicated that the CoVPSA peptide of the Spike protein elicits noticeable immunogenicity in vivo using a DC vaccine vector and remarkable cellular and humoral immune responses. This DC vaccine vector loaded with the NTD peptide of the Spike protein elicited a predominant Th1-Th17 cytokine profile, indicative of an effective anti-viral response. Finally, we performed a proof of concept experiment in humans that included the following groups: asymptomatic non-active COVID-19 patients, vaccinated volunteers, and control donors that tested negative for SARS-CoV-2. The positive control was the current receptor binding domain epitope of COVID-19 RNA-vaccines. We successfully developed a vaccine candidate technique involving optimizing lambda-superstrings and provided proof of concept in human subjects. We conclude that it is a valid method to decipher the best epitopes of the Spike protein of SARS-CoV-2 to prepare peptide-based vaccines for different vector platforms, including DC vaccines.
Age-related changes to vestibular heave and pitch perception and associations with postural control
Authors: Gabriel Grace A. , Harris Laurence R. , Gnanasegaram Joshua J. , Cushing Sharon L. , Gordon Karen A. , Haycock Bruce C. , Campos Jennifer L.
Published: April 2022

Falls are a common cause of injury in older adults (OAs), and age-related declines across the sensory systems are associated with increased falls risk. The vestibular system is particularly important for maintaining balance and supporting safe mobility, and aging has been associated with declines in vestibular end-organ functioning. However, few studies have examined potential age-related differences in vestibular perceptual sensitivities or their association with postural stability. Here we used an adaptive-staircase procedure to measure detection and discrimination thresholds in 19 healthy OAs and 18 healthy younger adults (YAs), by presenting participants with passive heave (linear up-and-down translations) and pitch (forward–backward tilt rotations) movements on a motion-platform in the dark. We also examined participants’ postural stability under various standing-balance conditions. Associations among these postural measures and vestibular perceptual thresholds were further examined. Ultimately, OAs showed larger heave and pitch detection thresholds compared to YAs, and larger perceptual thresholds were associated with greater postural sway, but only in OAs. Overall, these results suggest that vestibular perceptual sensitivity declines with older age and that such declines are associated with poorer postural stability. Future studies could consider the potential applicability of these results in the development of screening tools for falls prevention in OAs.
Decomposing rural–urban differences in successful aging among older Indian adults
Authors: Muhammad T. , Srivastava Shobhit , Hossain Babul , Paul Ronak , Sekher T. V.
Published: April 2022

The modernization and shift towards urbanized lifestyles have triggered several diseases, and the context of aging varies in urban and rural settings in India. The study aimed to investigate the urban–rural differences in successful ageing among older adults in India and the contributing factors in those differences. The study utilizes data from nationally representative Longitudinal Ageing Study in India (LASI, 2017–18). The analytical sample size for the study was 31,464 older adults aged 60 years and above. Descriptive statistics and bivariate analysis were carried out to present the initial results. Multivariable logistic regression and decomposition analysis was used to find the associations between explanatory variables and successful aging and to identify the contributions of covariates that explain the rural–urban differences in successful ageing. A proportion of 32% and 24% of older adults from rural and urban areas were successful agers with an urban disadvantage. Urban-dwelling older adults had 0.67 times [95% confidence interval (CI): (0.64, 0.71)] lower unadjusted odds of successful ageing than rural older adults. Again, after adjusting for the effect of other explanatory variables, urban older adults had 0.92 times [CI: (0.87, 0.98)] lower odds of being successful agers than their rural counterparts. The major contributors to the rural–urban inequality in successful aging were differences in regional distribution (17% contribution), waist circumference (16%), working status (16%), body mass index (13%) and physical activity (8%) among rural and urban older adults. The urban disadvantage in aging successfully may reflect the higher prevalence of adverse lifestyle behaviours in urban dwellers and under-diagnosis and under-reporting of many diseases in rural areas, particularly non-communicable diseases, suggesting the need for further investigation.
Investigating mental workload-induced changes in cortical oxygenation and frontal theta activity during simulated flights
Authors: Hamann Anneke , Carstengerdes Nils
Published: April 2022

Monitoring pilots’ cognitive states becomes increasingly important in aviation. Physiological measurement can detect increased mental workload (MWL) even before performance declines. Yet, changes in MWL are rarely varied systematically and few studies control for confounding effects of other cognitive states. The present study targets these shortcomings by analysing the effects of stepwise increased MWL on cortical activation, while controlling for mental fatigue (MF). 35 participants conducted a simulated flight with an incorporated adapted n-back and monitoring task. We recorded cortical activation with concurrent EEG and fNIRS measurement, performance, self-reported MWL and MF. Our results show the successful manipulation of MWL without confounding effects of MF. Higher task difficulty elicited higher subjective MWL ratings, performance decline, higher frontal theta activity and reduced frontal deoxyhaemoglobin (Hbr) concentration. Using both EEG and fNIRS, we could discriminate all induced MWL levels. fNIRS was more sensitive to tasks with low difficulty, and EEG to tasks with high difficulty. Our findings further suggest a plateau effect for high MWL that could present an upper boundary to individual cognitive capacity. Our results highlight the benefits of physiological measurement in aviation, both for assessment of cognitive states and as a data source for adaptive assistance systems.
Rapid evolution of SARS-CoV-2 challenges human defenses
Authors: Duarte Carlos M. , Ketcheson David I. , Eguíluz Víctor M. , Agustí Susana , Fernández-Gracia Juan , Jamil Tahira , Laiolo Elisa , Gojobori Takashi , Alam Intikhab
Published: April 2022

The race between pathogens and their hosts is a major evolutionary driver, where both reshuffle their genomes to overcome and reorganize the defenses for infection, respectively. Evolutionary theory helps formulate predictions on the future evolutionary dynamics of SARS-CoV-2, which can be monitored through unprecedented real-time tracking of SARS-CoV-2 population genomics at the global scale. Here we quantify the accelerating evolution of SARS-CoV-2 by tracking the SARS-CoV-2 mutation globally, with a focus on the Receptor Binding Domain (RBD) of the spike protein determining infection success. We estimate that the > 820 million people that had been infected by October 5, 2021, produced up to 1021 copies of the virus, with 12 new effective RBD variants appearing, on average, daily. Doubling of the number of RBD variants every 89 days, followed by selection of the most infective variants challenges our defenses and calls for a shift to anticipatory, rather than reactive tactics involving collaborative global sequencing and vaccination.
Prediction of abdominal CT body composition parameters by thoracic measurements as a new approach to detect sarcopenia in a COVID-19 cohort
Authors: Molwitz I. , Ozga A. K. , Gerdes L. , Ungerer A. , Köhler D. , Ristow I. , Leiderer M. , Adam G. , Yamamura J.
Published: April 2022

As most COVID-19 patients only receive thoracic CT scans, but body composition, which is relevant to detect sarcopenia, is determined in abdominal scans, this study aimed to investigate the relationship between thoracic and abdominal CT body composition parameters in a cohort of COVID-19 patients. This retrospective study included n = 46 SARS-CoV-2-positive patients who received CT scans of the thorax and abdomen due to severe disease progression. The subcutaneous fat area (SF), the skeletal muscle area (SMA), and the muscle radiodensity attenuation (MRA) were measured at the level of the twelfth thoracic (T12) and the third lumbar (L3) vertebra. Necessity of invasive mechanical ventilation (IMV), length of stay, or time to death (TTD) were noted. For statistics correlation, multivariable linear, logistic, and Cox regression analyses were employed. Correlation was excellent for the SF (r = 0.96) between T12 and L3, and good for the respective SMA (r = 0.80) and MRA (r = 0.82) values. With adjustment (adj.) for sex, age, and body-mass-index the variability of SF (adj. r2 = 0.93; adj. mean difference = 1.24 [95% confidence interval (95% CI) 1.02–1.45]), of the SMA (adj. r2 = 0.76; 2.59 [95% CI 1.92–3.26]), and of the MRA (adj. r2 = 0.67; 0.67 [95% CI 0.45–0.88]) at L3 was well explained by the respective values at T12. There was no relevant influence of the SF, MRA, or SMA on the clinical outcome. If only thoracic CT scans are available, CT body composition values at T12 can be used to predict abdominal fat and muscle parameters, by which sarcopenia and obesity can be assessed.
Factors influencing wind turbine avoidance behaviour of a migrating soaring bird
Authors: Santos Carlos D. , Ramesh Hariprasath , Ferraz Rafael , Franco Aldina M. A. , Wikelski Martin
Published: April 2022

Wind energy production has expanded as an alternative to carbon emitting fossil fuels, but is causing impacts on wildlife that need to be addressed. Soaring birds show concerning rates of collision with turbine rotor blades and losses of critical habitat. However, how these birds interact with wind turbines is poorly understood. We analyzed high-frequency GPS tracking data of 126 black kites (Milvus migrans) moving near wind turbines to identify behavioural mechanisms of turbine avoidance and their interaction with environmental variables. Birds flying within 1000 m from turbines and below the height of rotor blades were less likely to be oriented towards turbines than expected by chance, this pattern being more striking at distances less than 750 m. Within the range of 750 m, birds showed stronger avoidance when pushed by the wind in the direction of the turbines. Birds flying above the turbines did not change flight directions with turbine proximity. Sex and age of birds, uplift conditions and turbine height, showed no effect on flight directions although these factors have been pointed as important drivers of turbine collision by soaring birds. Our findings suggest that migrating black kites recognize the presence of wind turbines and behave in a way to avoid then. This may explain why this species presents lower collision rates with wind turbines than other soaring birds. Future studies should clarify if turbine avoidance behaviour is common to other soaring birds, particularly those that are facing high fatality rates due to collision.