bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platinum single-atom catalyst coupled with transition metal/metal oxide heterostructure for accelerating alkaline hydrogen evolution reaction
Authors: Zhou Kai Ling , Wang Zelin , Han Chang Bao , Ke Xiaoxing , Wang Changhao , Jin Yuhong , Zhang Qianqian , Liu Jingbing , Wang Hao , Yan Hui 
Published: June 2021

AbstractSingle-atom catalysts provide an effective approach to reduce the amount of precious metals meanwhile maintain their catalytic activity. However, the sluggish activity of the catalysts for alkaline water dissociation has hampered advances in highly efficient hydrogen production. Herein, we develop a single-atom platinum immobilized NiO/Ni heterostructure (PtSA-NiO/Ni) as an alkaline hydrogen evolution catalyst. It is found that Pt single atom coupled with NiO/Ni heterostructure enables the tunable binding abilities of hydroxyl ions (OH*) and hydrogen (H*), which efficiently tailors the water dissociation energy and promotes the H* conversion for accelerating alkaline hydrogen evolution reaction. A further enhancement is achieved by constructing PtSA-NiO/Ni nanosheets on Ag nanowires to form a hierarchical three-dimensional morphology. Consequently, the fabricated PtSA-NiO/Ni catalyst displays high alkaline hydrogen evolution performances with a quite high mass activity of 20.6 A mg−1 for Pt at the overpotential of 100 mV, significantly outperforming the reported catalysts.
Structural basis for the ARF GAP activity and specificity of the C9orf72 complex
Authors: Su Ming-Yuan , Fromm Simon A. , Remis Jonathan , Toso Daniel B. , Hurley James H. 
Published: June 2021

AbstractMutation of C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontal temporal degeneration (FTD), which is attributed to both a gain and loss of function. C9orf72 forms a complex with SMCR8 and WDR41, which was reported to have GTPase activating protein activity toward ARF proteins, RAB8A, and RAB11A. We determined the cryo-EM structure of ARF1-GDP-BeF3- bound to C9orf72:SMCR8:WDR41. The SMCR8longin and C9orf72longin domains form the binding pocket for ARF1. One face of the C9orf72longin domain holds ARF1 in place, while the SMCR8longin positions the catalytic finger Arg147 in the ARF1 active site. Mutations in interfacial residues of ARF1 and C9orf72 reduced or eliminated GAP activity. RAB8A GAP required ~10-fold higher concentrations of the C9orf72 complex than for ARF1. These data support a specific function for the C9orf72 complex as an ARF GAP. The structure also provides a model for the active forms of the longin domain GAPs of FLCN and NPRL2 that regulate the Rag GTPases of the mTORC1 pathway.
Structural insights into an atypical secretory pathway kinase crucial for Toxoplasma gondii invasion
Authors: Lentini Gaëlle , Ben Chaabene Rouaa , Vadas Oscar , Ramakrishnan Chandra , Mukherjee Budhaditya , Mehta Ved , Lunghi Matteo , Grossmann Jonas , Maco Bohumil , Visentin Rémy , Hehl Adrian B. , Korkhov Volodymyr M. , Soldati-Favre Dominique 
Published: June 2021

AbstractActive host cell invasion by the obligate intracellular apicomplexan parasites relies on the formation of a moving junction, which connects parasite and host cell plasma membranes during entry. Invading Toxoplasma gondii tachyzoites secrete their rhoptry content and insert a complex of RON proteins on the cytoplasmic side of the host cell membrane providing an anchor to which the parasite tethers. Here we show that a rhoptry-resident kinase RON13 is a key virulence factor that plays a crucial role in host cell entry. Cryo-EM, kinase assays, phosphoproteomics and cellular analyses reveal that RON13 is a secretory pathway kinase of atypical structure that phosphorylates rhoptry proteins including the components of the RON complex. Ultimately, RON13 kinase activity controls host cell invasion by anchoring the moving junction at the parasite-host cell interface.
Live-cell imaging of circadian clock protein dynamics in CRISPR-generated knock-in cells
Authors: Gabriel Christian H. , del Olmo Marta , Zehtabian Amin , Jäger Marten , Reischl Silke , van Dijk Hannah , Ulbricht Carolin , Rakhymzhan Asylkhan , Korte Thomas , Koller Barbara , Grudziecki Astrid , Maier Bert , Herrmann Andreas , Niesner Raluca , Zemojtel Tomasz , Ewers Helge , Granada Adrián E. , Herzel Hanspeter , Kramer Achim 
Published: June 2021

AbstractThe cell biology of circadian clocks is still in its infancy. Here, we describe an efficient strategy for generating knock-in reporter cell lines using CRISPR technology that is particularly useful for genes expressed transiently or at low levels, such as those coding for circadian clock proteins. We generated single and double knock-in cells with endogenously expressed PER2 and CRY1 fused to fluorescent proteins allowing us to simultaneously monitor the dynamics of CRY1 and PER2 proteins in live single cells. Both proteins are highly rhythmic in the nucleus of human cells with PER2 showing a much higher amplitude than CRY1. Surprisingly, CRY1 protein is nuclear at all circadian times indicating the absence of circadian gating of nuclear import. Furthermore, in the nucleus of individual cells CRY1 abundance rhythms are phase-delayed (~5 hours), and CRY1 levels are much higher (>5 times) compared to PER2 questioning the current model of the circadian oscillator.
Nickel-catalysed migratory hydroalkynylation and enantioselective hydroalkynylation of olefins with bromoalkynes
Authors: Jiang Xiaoli , Han Bo , Xue Yuhang , Duan Mei , Gui Zhuofan , Wang You , Zhu Shaolin 
Published: June 2021

Abstractα-Chiral alkyne is a key structural element of many bioactive compounds, chemical probes, and functional materials, and is a valuable synthon in organic synthesis. Here we report a NiH-catalysed reductive migratory hydroalkynylation of olefins with bromoalkynes that delivers the corresponding benzylic alkynylation products in high yields with excellent regioselectivities. Catalytic enantioselective hydroalkynylation of styrenes has also been realized using a simple chiral PyrOx ligand. The obtained enantioenriched benzylic alkynes are versatile synthetic intermediates and can be readily transformed into synthetically useful chiral synthons.
TERRA transcription destabilizes telomere integrity to initiate break-induced replication in human ALT cells
Authors: Silva Bruno , Arora Rajika , Bione Silvia , Azzalin Claus M. 
Published: June 2021

AbstractAlternative Lengthening of Telomeres (ALT) is a Break-Induced Replication (BIR)-based mechanism elongating telomeres in a subset of human cancer cells. While the notion that spontaneous DNA damage at telomeres is required to initiate ALT, the molecular triggers of this physiological telomere instability are largely unknown. We previously proposed that the telomeric long noncoding RNA TERRA may represent one such trigger; however, given the lack of tools to suppress TERRA transcription in cells, our hypothesis remained speculative. We have developed Transcription Activator-Like Effectors able to rapidly inhibit TERRA transcription from multiple chromosome ends in an ALT cell line. TERRA transcription inhibition decreases marks of DNA replication stress and DNA damage at telomeres and impairs ALT activity and telomere length maintenance. We conclude that TERRA transcription actively destabilizes telomere integrity in ALT cells, thereby triggering BIR and promoting telomere elongation. Our data point to TERRA transcription manipulation as a potentially useful target for therapy.
Large model structural uncertainty in global projections of urban heat waves
Authors: Zheng Zhonghua , Zhao Lei , Oleson Keith W. 
Published: June 2021

AbstractUrban heat waves (UHWs) are strongly associated with socioeconomic impacts. Here, we use an urban climate emulator combined with large ensemble global climate simulations to show that, at the urban scale a large proportion of the variability results from the model structural uncertainty in projecting UHWs in the coming decades under climate change. Omission of this uncertainty would considerably underestimate the risk of UHW. Results show that, for cities in four high-stake regions – the Great Lakes of North America, Southern Europe, Central India, and North China – a virtually unlikely (0.01% probability) UHW projected by single-model ensembles is estimated by our model with probabilities of 23.73%, 4.24%, 1.56%, and 14.76% respectively in 2061–2070 under a high-emission scenario. Our findings suggest that for urban-scale extremes, policymakers and stakeholders will have to plan for larger uncertainties than what a single model predicts if decisions are informed based on urban climate simulations.
Association of social distancing and face mask use with risk of COVID-19
Authors: Kwon Sohee , Joshi Amit D. , Lo Chun-Han , Drew David A. , Nguyen Long H. , Guo Chuan-Guo , Ma Wenjie , Mehta Raaj S. , Shebl Fatma Mohamed , Warner Erica T. , Astley Christina M. , Merino Jordi , Murray Benjamin , Wolf Jonathan , Ourselin Sebastien , Steves Claire J. , Spector Tim D. , Hart Jaime E. , Song Mingyang , VoPham Trang , Chan Andrew T. 
Published: June 2021

AbstractGiven the continued burden of COVID-19 worldwide, there is a high unmet need for data on the effect of social distancing and face mask use to mitigate the risk of COVID-19. We examined the association of community-level social distancing measures and individual face mask use with risk of predicted COVID-19 in a large prospective U.S. cohort study of 198,077 participants. Individuals living in communities with the greatest social distancing had a 31% lower risk of predicted COVID-19 compared with those living in communities with poor social distancing. Self-reported ‘always’ use of face mask was associated with a 62% reduced risk of predicted COVID-19 even among individuals living in a community with poor social distancing. These findings provide support for the efficacy of mask-wearing even in settings of poor social distancing in reducing COVID-19 transmission. Despite mass vaccination campaigns in many parts of the world, continued efforts at social distancing and face mask use remain critically important in reducing the spread of COVID-19.
Acinetobacter baylyi regulates type IV pilus synthesis by employing two extension motors and a motor protein inhibitor
Authors: Ellison Courtney K. , Dalia Triana N. , Klancher Catherine A. , Shaevitz Joshua W. , Gitai Zemer , Dalia Ankur B. 
Published: June 2021

AbstractBacteria use extracellular appendages called type IV pili (T4P) for diverse behaviors including DNA uptake, surface sensing, virulence, protein secretion, and twitching motility. Dynamic extension and retraction of T4P is essential for their function, and T4P extension is thought to occur through the action of a single, highly conserved motor, PilB. Here, we develop Acinetobacter baylyi as a model to study T4P by employing a recently developed pilus labeling method. By contrast to previous studies of other bacterial species, we find that T4P synthesis in A. baylyi is dependent not only on PilB but also on an additional, phylogenetically distinct motor, TfpB. Furthermore, we identify a protein (CpiA) that inhibits T4P extension by specifically binding and inhibiting PilB but not TfpB. These results expand our understanding of T4P regulation and highlight how inhibitors might be exploited to disrupt T4P synthesis.
Tailored cobalt-salen complexes enable electrocatalytic intramolecular allylic C–H functionalizations
Authors: Cai Chen-Yan , Wu Zheng-Jian , Liu Ji-Ying , Chen Ming , Song Jinshuai , Xu Hai-Chao 
Published: June 2021

AbstractOxidative allylic C–H functionalization is a powerful tool to streamline organic synthesis as it minimizes the need for functional group activation and generates alkenyl-substituted products amenable to further chemical modifications. The intramolecular variants can be used to construct functionalized ring structures but remain limited in scope and by their frequent requirement for noble metal catalysts and stoichiometric chemical oxidants. Here we report an oxidant-free, electrocatalytic approach to achieve intramolecular oxidative allylic C–H amination and alkylation by employing tailored cobalt-salen complexes as catalysts. These reactions proceed through a radical mechanism and display broad tolerance of functional groups and alkene substitution patterns, allowing efficient coupling of di-, tri- and even tetrasubstituted alkenes with N- and C-nucleophiles to furnish high-value heterocyclic and carbocyclic structures.
Establishment and characterization of immortalized human breast cancer cell lines from breast cancer patient-derived xenografts (PDX)
Authors: Zhuang Yongxian , Grainger Jordan M. , Vedell Peter T. , Yu Jia , Moyer Ann M. , Gao Huanyao , Fan Xiao-Yang , Qin Sisi , Liu Duan , Kalari Krishna R. , Goetz Matthew P. , Boughey Judy C. , Weinshilboum Richard M. , Wang Liewei 
Published: June 2021

AbstractThe application of patient-derived xenografts (PDX) in drug screening and testing is a costly and time-consuming endeavor. While cell lines permit extensive mechanistic studies, many human breast cancer cell lines lack patient characteristics and clinical treatment information. Establishing cell lines that retain patient’s genetic and drug response information would enable greater drug screening and mechanistic studies. Therefore, we utilized breast cancer PDX from the Mayo Breast Cancer Genome Guided Therapy Study (BEAUTY) to establish two immortalized, genomically unique breast cancer cell lines. Through extensive genetic and therapeutic testing, the cell lines were found to retain the same clinical subtype, major somatic alterations, and drug response phenotypes as their corresponding PDX and patient tumor. Our findings demonstrate PDX can be utilized to develop immortalized breast cancer cell lines and provide a valuable tool for understanding the molecular mechanism of drug resistance and exploring novel treatment strategies.
High-energy magnetic excitations from heavy quasiparticles in CeCu2Si2
Authors: Song Yu , Wang Weiyi , Cao Chongde , Yamani Zahra , Xu Yuanji , Sheng Yutao , Löser Wolfgang , Qiu Yiming , Yang Yi-feng , Birgeneau Robert J. , Dai Pengcheng 
Published: June 2021

AbstractMagnetic fluctuations is the leading candidate for pairing in cuprate, iron-based, and heavy fermion superconductors. This view is challenged by the recent discovery of nodeless superconductivity in CeCu2Si2, and calls for a detailed understanding of the corresponding magnetic fluctuations. Here, we mapped out the magnetic excitations in superconducting (S-type) CeCu2Si2 using inelastic neutron scattering, finding a strongly asymmetric dispersion for E ≲ 1.5 meV, which at higher energies evolves into broad columnar magnetic excitations that extend to E ≳ 5 meV. While low-energy magnetic excitations exhibit marked three-dimensional characteristics, the high-energy magnetic excitations in CeCu2Si2 are almost two-dimensional, reminiscent of paramagnons found in cuprate and iron-based superconductors. By comparing our experimental findings with calculations in the random-phase approximation,we find that the magnetic excitations in CeCu2Si2 arise from quasiparticles associated with its heavy electron band, which are also responsible for superconductivity. Our results provide a basis for understanding magnetism and superconductivity in CeCu2Si2, and demonstrate the utility of neutron scattering in probing band renormalization in heavy fermion metals.
3D conformal bandpass millimeter-wave frequency selective surface with improved fields of view
Authors: Álvarez H. Fernández , Cadman Darren A. , Goulas Athanasios , de Cos Gómez M. E. , Engstrøm Daniel S. , Vardaxoglou J. C. , Zhang Shiyu 
Published: June 2021

AbstractConventional planar frequency selective surfaces (FSSs) are characterized in the far-field region and they are sensitive to the incidence angle of impinging waves. In this paper, a spherical dome FSS is presented, aiming to provide improved angular stable bandpass filtering performance as compared to its planar counterpart when the FSS is placed in the near-field region of an antenna source. A comparison between the conformal FSS and a finite planar FSS is presented through simulations at the frequency range between 26 to 40 GHz in order to demonstrate the advantages of utilizing the conformal FSS in the near-field. The conformal FSS is 3D printed and copper electroplated, which leads to a low-cost and lightweight bandpass filter array. Placing it in the near-field region of a primary antenna can be used as radomes to realize compact high-performance mm-wave systems. The comparison between simulated and measured conformal FSS results is in good agreement. The challenges that arise when designing, manufacturing, and measuring this type of structure are reported and guidelines to overcome these are presented.
Gender specific airway gene expression in COPD sub-phenotypes supports a role of mitochondria and of different types of leukocytes
Authors: Esteve-Codina Anna , Hofer Thomas P. , Burggraf Dorothe , Heiss-Neumann Marion S. , Gesierich Wolfgang , Boland Anne , Olaso Robert , Bihoreau Marie-Therese , Deleuze Jean-Francois , Moeller Winfried , Schmid Otmar , Soler Artigas María , Renner Kathrin , Hohlfeld Jens M. , Welte Tobias , Fuehner Thomas , Jerrentrup Lukas , Koczulla Andreas Rembert , Greulich Timm , Prasse Antje , Müller-Quernheim Joachim , Gupta Sumit , Brightling Christopher , Subramanian Deepak R. , Parr David G. , Kolsum Umme , Gupta Vandana , Barta Imre , Döme Balázs , Strausz János , Stendardo Mariarita , Piattella Marco , Boschetto Piera , Korzybski Damian , Gorecka Dorota , Nowinski Adam , Dabad Marc , Fernández-Callejo Marcos , Endesfelder David , zu Castell Wolfgang , Hiemstra Pieter S. , Venge Per , Noessner Elfriede , Griebel Thasso , Heath Simon , Singh Dave , Gut Ivo , Ziegler-Heitbrock Loems 
Published: June 2021

AbstractChronic obstructive pulmonary disease (COPD) is a destructive inflammatory disease and the genes expressed within the lung are crucial to its pathophysiology. We have determined the RNAseq transcriptome of bronchial brush cells from 312 stringently defined ex-smoker patients. Compared to healthy controls there were for males 40 differentially expressed genes (DEGs) and 73 DEGs for females with only 26 genes shared. The gene ontology (GO) term “response to bacterium” was shared, with several different DEGs contributing in males and females. Strongly upregulated genes TCN1 and CYP1B1 were unique to males and females, respectively. For male emphysema (E)-dominant and airway disease (A)-dominant COPD (defined by computed tomography) the term “response to stress” was found for both sub-phenotypes, but this included distinct up-regulated genes for the E-sub-phenotype (neutrophil-related CSF3R, CXCL1, MNDA) and for the A-sub-phenotype (macrophage-related KLF4, F3, CD36). In E-dominant disease, a cluster of mitochondria-encoded (MT) genes forms a signature, able to identify patients with emphysema features in a confirmation cohort. The MT-CO2 gene is upregulated transcriptionally in bronchial epithelial cells with the copy number essentially unchanged. Both MT-CO2 and the neutrophil chemoattractant CXCL1 are induced by reactive oxygen in bronchial epithelial cells. Of the female DEGs unique for E- and A-dominant COPD, 88% were detected in females only. In E-dominant disease we found a pronounced expression of mast cell-associated DEGs TPSB2, TPSAB1 and CPA3. The differential genes discovered in this study point towards involvement of different types of leukocytes in the E- and A-dominant COPD sub-phenotypes in males and females.
Two new long-rostrum cranefly species from the Cretaceous Iberian amber (Diptera, Limoniidae, Helius)
Authors: Kania-Kłosok Iwona , Krzemiński Wiesław , Arillo Antonio 
Published: June 2021

AbstractFirst record of the genus Helius—long-rostrum cranefly from Maestrazgo Basin (eastern Spain, Iberian Penisula) is documented. Two new fossil species of the genus Helius are described from Cretaceous Spanish amber and compared with other species of the genus known from fossil record with particular references to these known from Cretaceous period. Helius turolensis sp. nov. is described from San Just amber (Lower Cretaceous, upper Albian) Maestrazgo Basin, eastern Spain, and Helius hispanicus sp. nov. is described from Álava amber (Lower Cretaceous, upper Albian), Basque-Cantabrian Basin, northern Spain. The specific body morphology of representatives of the genus Helius preserved in Spanish amber was discussed in relation to the environmental conditions of the Maestrazgo Basin and Basque-Cantabrian Basin in Cretaceous.
Inverse-designed ultra-compact high efficiency and low crosstalk optical interconnect based on waveguide crossing and wavelength demultiplexer
Authors: Xu Yanhong , Huang Jie , Yang Lina , Ma Hansi , Yuan Huan , Xie Tong , Yang Junbo , Zhang Zhenrong 
Published: June 2021

AbstractIn this paper, we use the inverse design method to design an optical interconnection system composed of wavelength demultiplexer and the same direction waveguide crossing on silicon-on-insulator (SOI) platform. A 2.4 μm × 3.6 μm wavelength demultiplexer with an input wavelength of 1.3–1.6 μm is designed. When the target wavelength of the device is 1.4 μm, the insertion loss of the output port is − 0.93 dB, and there is − 18.4 dB crosstalk, in TE0 mode. The insertion loss of the target wavelength of 1.6 μm in TE0 mode is − 0.88 dB, and the crosstalk is − 19.1 dB. Then, we designed a same direction waveguide crossing, the footprint is only 2.4 μm × 3.6 μm, the insertion loss of the wavelength 1.4 μm and 1.6 μm in TE0 mode is − 0.99 dB and − 1 dB, and the crosstalk is − 12.14 dB and − 14.34 dB, respectively. Finally, an optical interconnect structure composed of two devices is used, which can become the most basic component of the optical interconnect network. In TE0 mode, the insertion loss of the output wavelength of 1.4 μm at the output port is − 1.3 dB, and the crosstalk is − 29.36 dB. The insertion loss of the output wavelength of 1.6 μm is − 1.39 dB, and the crosstalk is − 38.99 dB.
Virtual reality and annotated radiological data as effective and motivating tools to help Social Sciences students learn neuroanatomy
Authors: van Deursen Margot , Reuvers Laura , Duits Jacobus Dylan , de Jong Guido , van den Hurk Marianne , Henssen Dylan 
Published: June 2021

AbstractNeuroanatomy as a subject is important to learn, because a good understanding of neuroanatomy supports the establishment of a correct diagnosis in neurological patients. However, rapid changes in curricula reduced time assigned to study (neuro)anatomy. Therefore, it is important to find alternative teaching methods to study the complex three-dimensional structure of the brain. The aim of this manuscript was to explore the effectiveness of Virtual Reality (VR) in comparison with Radiological Data (RaD) as suitable learning methods to build knowledge and increase motivation for learning neuroanatomy. Forty-seven students (mean age of 19.47 ± 0.54 years; 43 females; 4 males) were included; 23 students comprised the VR group. Both methods showed to improve knowledge significantly, the improvement between groups was not different. The RaD group showed to have a significantly higher score on expectancy than students in the VR group. Task value scores regarding finding a task interesting, useful and fun were found to be significantly different in favor of the VR group. Consequently, significant higher Motivation scores were found in the VR group. Motivation and expectancy, however, did not moderate learning results, whereas task value impacted the results in favour of the VR group. This study concludes that VR and RaD are effective and diverting methods to learn neuroanatomy, with VR being more motivating than RaD. Future research should investigate motivation and task value when using VR over a longer period of time.