bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controls on the Width of Tropical Precipitation and Its Contraction Under Global Warming
Authors: Donohoe A. , Atwood A. R. , Byrne M. P. 
Published: June 2019

AbstractClimate models robustly and unanimously simulate narrowing of the intense tropical precipitation under greenhouse gas forcing. We argue that the meridional width of tropical precipitation is controlled by the seasonal meridional range of the Intertropical Convergence Zone (ITCZ). The contraction of tropical precipitation under greenhouse forcing results from a reduced seasonal range of ITCZ migration. An energetic theory—similar to the energetic theory for ITCZ shifts based on the hemispheric contrast of energy input to the atmosphere—is developed. The meridional width of tropical precipitation is proportional to the seasonal range of the interhemispheric contrast in atmospheric heating divided by the efficiency of atmospheric cross‐equatorial heat transport. Climate models are biased toward overly expansive tropical precipitation resulting from an exaggerated seasonal atmospheric heating. The robust contraction of tropical precipitation under global warming results from increased efficiency of interhemispheric energy transport consistent with enhanced gross moist stability of the tropical atmosphere.
Thermal Weakening, Convergent Flow, and Vertical Heat Transport in the Northeast Greenland Ice Stream Shear Margins
Authors: Holschuh N. , Lilien D. A. , Christianson K. 
Published: June 2019

AbstractIce streams are bounded by abrupt transitions in speed called shear margins. Some shear margins are fixed by subglacial topography, but others are thought to be self‐organizing, evolving by thermal feedback to ice viscosity and basal drag which govern the stress balance of ice sheets. Resistive stresses (and properties governing shear‐margin formation) manifest nonuniquely at the surface, motivating the use of subsurface observations to constrain ice sheet models. In this study, we use ice‐penetrating radar data to evaluate three 3‐D thermomechanical models of the Northeast Greenland Ice Stream, focusing on model reproductions of ice temperature (a primary control on viscosity) and subsurface velocity. Data/model agreement indicates elevated temperatures in the Northeast Greenland Ice Stream margins, with depth‐averaged temperatures between 2 °C and 6 °C warmer in the southeast margin compared to ice in streaming flow, driven by vertical heat transport rather than shear heating. This work highlights complexity in ice divergence across stagnant/streaming transitions.
Impact of polymorphism on the optoelectronic properties of a low-bandgap semiconducting polymer
Authors: Li Mengmeng , Balawi Ahmed Hesham , Leenaers Pieter J. , Ning Lu , Heintges Gaël H. L. , Marszalek Tomasz , Pisula Wojciech , Wienk Martijn M. , Meskers Stefan C. J. , Yi Yuanping , Laquai Frédéric , Janssen René A. J. 
Published: June 2019

AbstractPolymorphism of organic semiconducting materials exerts critical effects on their physical properties such as optical absorption, emission and electrical conductivity, and provides an excellent platform for investigating structure–property relations. It is, however, challenging to efficiently tune the polymorphism of conjugated polymers in aggregated, semi-crystalline phases due to their conformational freedom and anisotropic nature. Here, two distinctly different semi-crystalline polymorphs (β1 and β2) of a low-bandgap diketopyrrolopyrrole polymer are formed through controlling the solvent quality, as evidenced by spectroscopic, structural, thermal and charge transport studies. Compared to β1, the β2 polymorph exhibits a lower optical band gap, an enhanced photoluminescence, a reduced π-stacking distance, a higher hole mobility in field-effect transistors and improved photocurrent generation in polymer solar cells. The β1 and β2 polymorphs provide insights into the control of polymer self-organization for plastic electronics and hold potential for developing programmable ink formulations for next-generation electronic devices.
Marrying chemistry with biology by combining on-chip solution-based combinatorial synthesis and cellular screening
Authors: Benz Maximilian , Molla Mijanur R. , Böser Alexander , Rosenfeld Alisa , Levkin Pavel A. 
Published: June 2019

AbstractDrug development often relies on high-throughput cell-based screening of large compound libraries. However, the lack of miniaturized and parallelized methodologies in chemistry as well as strict separation and incompatibility of the synthesis of bioactive compounds from their biological screenings makes this process expensive and inefficient. Here, we demonstrate an on-chip platform that combines solution-based synthesis of compound libraries with high-throughput biological screenings (chemBIOS). The chemBIOS platform is compatible with both organic solvents required for the synthesis and aqueous solutions necessary for biological screenings. We use the chemBIOS platform to perform 75 parallel, three-component reactions to synthesize a library of lipidoids, followed by characterization via MALDI-MS, on-chip formation of lipoplexes, and on-chip cell screening. The entire process from the library synthesis to cell screening takes only 3 days and about 1 mL of total solutions, demonstrating the potential of the chemBIOS technology to increase efficiency and accelerate screenings and drug development.
Chromatin organization in the female mouse brain fluctuates across the oestrous cycle
Authors: Jaric Ivana , Rocks Devin , Greally John M. , Suzuki Masako , Kundakovic Marija 
Published: June 2019

AbstractMale and female brains differ significantly in both health and disease, and yet the female brain has been understudied. Sex-hormone fluctuations make the female brain particularly dynamic and are likely to confer female-specific risks for neuropsychiatric disorders. The molecular mechanisms underlying the dynamic nature of the female brain structure and function are unknown. Here we show that neuronal chromatin organization in the female ventral hippocampus of mouse fluctuates with the oestrous cycle. We find chromatin organizational changes associated with the transcriptional activity of genes important for neuronal function and behaviour. We link these chromatin dynamics to variation in anxiety-related behaviour and brain structure. Our findings implicate an immediate-early gene product, Egr1, as part of the mechanism mediating oestrous cycle-dependent chromatin and transcriptional changes. This study reveals extreme, sex-specific dynamism of the neuronal epigenome, and establishes a foundation for the development of sex-specific treatments for disorders such as anxiety and depression.
Early evidence of molariform hypsodonty in a Triassic stem-mammal
Authors: Melo Tomaz P. , Ribeiro Ana Maria , Martinelli Agustín G. , Soares Marina Bento 
Published: June 2019

AbstractHypsodonty, the occurrence of high-crowned teeth, is widespread among mammals with diets rich in abrasive material, such as plants or soil, because it increases the durability of dentitions against wear. Hypsodont postcanine teeth evolved independently in multiple mammalian lineages and in the closely related mammaliaforms since the Jurassic period. Here, we report the oldest record, to our knowledge, of hypsodont postcanines in the non-mammaliaform stem-mammal, Menadon besairiei, from the early Late Triassic. The postcanines are long and columnar, with open roots. They were not replaced in older individuals and remained functional after the total wear of the crown enamel. Dental histology suggests that, convergently to hypsodont mammals, wear was compensated by the prolonged growth of each postcanine, resulting in dentine hypsodont teeth most similar to extant xenarthran mammals. These findings highlight the constraints imposed by limited tooth replacement and tooth wear in the evolutionary trajectories of herbivorous mammals and stem-mammals.
A neurotoxin that specifically targets Anopheles mosquitoes
Authors: Contreras Estefania , Masuyer Geoffrey , Qureshi Nadia , Chawla Swati , Dhillon Harpal S. , Lee Han Lim , Chen Jianwu , Stenmark Pål , Gill Sarjeet S. 
Published: June 2019

AbstractClostridial neurotoxins, including tetanus and botulinum neurotoxins, generally target vertebrates. We show here that this family of toxins has a much broader host spectrum, by identifying PMP1, a clostridial-like neurotoxin that selectively targets anopheline mosquitoes. Isolation of PMP1 from Paraclostridium bifermentans strains collected in anopheline endemic areas on two continents indicates it is widely distributed. The toxin likely evolved from an ancestral form that targets the nervous system of similar organisms, using a common mechanism that disrupts SNARE-mediated exocytosis. It cleaves the mosquito syntaxin and employs a unique receptor recognition strategy. Our research has an important impact on the study of the evolution of clostridial neurotoxins and provides the basis for the use of P. bifermentans strains and PMP1 as innovative, environmentally friendly approaches to reduce malaria through anopheline control.
TSPAN8 promotes cancer cell stemness via activation of sonic Hedgehog signaling
Authors: Zhu Rongxuan , Gires Olivier , Zhu Liqun , Liu Jun , Li Junjian , Yang Hao , Ju Gaoda , Huang Jing , Ge Weiyu , Chen Yi , Lu Zhimin , Wang Hongxia 
Published: June 2019

AbstractCancer stem cells (CSCs) represent a major source of treatment resistance and tumor progression. However, regulation of CSCs stemness is not entirely understood. Here, we report that TSPAN8 expression is upregulated in breast CSCs, promotes the expression of the stemness gene NANOG, OCT4, and ALDHA1, and correlates with therapeutic resistance. Mechanistically, TSPAN8 interacts with PTCH1 and inhibits the degradation of the SHH/PTCH1 complex through recruitment of deubiquitinating enzyme ATXN3. This results in the translocation of SMO to cilia, downstream gene expression, resistance of CSCs to chemotherapeutic agents, and enhances tumor formation in mice. Accordingly, expression levels of TSPAN8, PTCH1, SHH, and ATXN3 are positively correlated in human breast cancer specimens, and high TSPAN8 and ATXN3 expression levels correlate with poor prognosis. These findings reveal a molecular basis of TSPAN8-enhanced Sonic Hedgehog signaling and highlight a role for TSPAN8 in promoting cancer stemness.
DNA double-strand breaks in telophase lead to coalescence between segregated sister chromatid loci
Authors: Ayra-Plasencia Jessel , Machín Félix 
Published: June 2019

AbstractDNA double strand breaks (DSBs) pose a high risk for genome integrity. Cells repair DSBs through homologous recombination (HR) when a sister chromatid is available. HR is upregulated by the cycling dependent kinase (CDK) despite the paradox of telophase, where CDK is high but a sister chromatid is not nearby. Here we study in the budding yeast the response to DSBs in telophase, and find they activate the DNA damage checkpoint (DDC), leading to a telophase-to-G1 delay. Outstandingly, we observe a partial reversion of sister chromatid segregation, which includes approximation of segregated material, de novo formation of anaphase bridges, and coalescence between sister loci. We finally show that DSBs promote a massive change in the dynamics of telophase microtubules (MTs), together with dephosphorylation and relocalization of kinesin-5 Cin8. We propose that chromosome segregation is not irreversible and that DSB repair using the sister chromatid is possible in telophase.
Dual pathways of tRNA hydroxylation ensure efficient translation by expanding decoding capability
Authors: Sakai Yusuke , Kimura Satoshi , Suzuki Tsutomu 
Published: June 2019

AbstractIn bacterial tRNAs, 5-carboxymethoxyuridine (cmo5U) and its derivatives at the first position of the anticodon facilitate non-Watson–Crick base pairing with guanosine and pyrimidines at the third positions of codons, thereby expanding decoding capabilities. However, their biogenesis and physiological roles remained to be investigated. Using reverse genetics and comparative genomics, we identify two factors responsible for 5-hydroxyuridine (ho5U) formation, which is the first step of the cmo5U synthesis: TrhP (formerly known as YegQ), a peptidase U32 family protein, is involved in prephenate-dependent ho5U formation; and TrhO (formerly known as YceA), a rhodanese family protein, catalyzes oxygen-dependent ho5U formation and bypasses cmo5U biogenesis in a subset of tRNAs under aerobic conditions. E. coli strains lacking both trhP and trhO exhibit a temperature-sensitive phenotype, and decode codons ending in G (GCG and UCG) less efficiently than the wild-type strain. These findings confirm that tRNA hydroxylation ensures efficient decoding during protein synthesis.
Crystal structure of an adenovirus virus-associated RNA
Authors: Hood Iris V. , Gordon Jackson M. , Bou-Nader Charles , Henderson Frances E. , Bahmanjah Soheila , Zhang Jinwei 
Published: June 2019

AbstractAdenovirus Virus-Associated (VA) RNAs are the first discovered viral noncoding RNAs. By mimicking double-stranded RNAs (dsRNAs), the exceptionally abundant, multifunctional VA RNAs sabotage host machineries that sense, transport, process, or edit dsRNAs. How VA-I suppresses PKR activation despite its strong dsRNA character, and inhibits the crucial antiviral kinase to promote viral translation, remains largely unknown. Here, we report a 2.7 Å crystal structure of VA-I RNA. The acutely bent VA-I features an unusually structured apical loop, a wobble-enriched, coaxially stacked apical and tetra-stems necessary and sufficient for PKR inhibition, and a central domain pseudoknot that resembles codon-anticodon interactions and prevents PKR activation by VA-I. These global and local structural features collectively define VA-I as an archetypal PKR inhibitor made of RNA. The study provides molecular insights into how viruses circumnavigate cellular rules of self vs non-self RNAs to not only escape, but further compromise host innate immunity.
Unusual 4H-phase twinned noble metal nanokites
Authors: Niu Wenxin , Liu Jiawei , Huang Jingtao , Chen Bo , He Qiyuan , Wang An-Liang , Lu Qipeng , Chen Ye , Yun Qinbai , Wang Jie , Li Cuiling , Huang Ying , Lai Zhuangchai , Fan Zhanxi , Wu Xue-Jun , Zhang Hua 
Published: June 2019

AbstractTwinning commonly exists in noble metals. In recent years, it has attracted increasing interest as it is powerful to tune the physicochemical properties of metallic nanomaterials. To the best of our knowledge, all the reported twinned noble metal structures exclusively possess the close-packed {111} twinning plane. Here, we report the discovery of non-close-packed twinning planes in our synthesized Au nanokites. By using the bent Au nanoribbons with unique 4H/face-centered cubic)/4H crystal-phase heterostructures as templates, Au nanokites with unusual twinned 4H-phase structures have been synthesized, which possess the non-close-packed {10$$\bar 1$$

1

¯

2} or {10$$\bar 1$$

1

¯

6} twinning plane. By using the Au nanokites as templates, twinned 4H-phase Au@Ag and Au@PdAg core-shell nanostructures have been synthesized. The discovery of 4H-phase twinned noble metal nanostructures may pave a way for the preparation of metal nanomaterials with unique twinned structures for various promising applications.
Transcription factor YcjW controls the emergency H2S production in E. coli
Authors: Luhachack Lyly , Rasouly Aviram , Shamovsky Ilya , Nudler Evgeny 
Published: June 2019

AbstractProkaryotes and eukaryotes alike endogenously generate the gaseous molecule hydrogen sulfide (H2S). Bacterial H2S acts as a cytoprotectant against antibiotics-induced stress and promotes redox homeostasis. In E. coli, endogenous H2S production is primarily dependent on 3-mercaptopyruvate sulfurtransferase (3MST), encoded by mstA. Here, we show that cells lacking 3MST acquire a phenotypic suppressor mutation resulting in compensatory H2S production and tolerance to antibiotics and oxidative stress. Using whole genome sequencing, we identified a non-synonymous mutation within an uncharacterized LacI-type transcription factor, ycjW. We then mapped regulatory targets of YcjW and discovered it controls the expression of carbohydrate metabolic genes and thiosulfate sulfurtransferase PspE. Induction of pspE expression in the suppressor strain provides an alternative mechanism for H2S biosynthesis. Our results reveal a complex interaction between carbohydrate metabolism and H2S production in bacteria and the role, a hitherto uncharacterized transcription factor, YcjW, plays in linking the two.
Site-specific cleavage of bacterial MucD by secreted proteases mediates antibacterial resistance in Arabidopsis
Authors: Wang Yiming , Garrido-Oter Ruben , Wu Jingni , Winkelmüller Thomas M. , Agler Matthew , Colby Thomas , Nobori Tatsuya , Kemen Eric , Tsuda Kenichi 
Published: June 2019

AbstractPlant innate immunity restricts growth of bacterial pathogens that threaten global food security. However, the mechanisms by which plant immunity suppresses bacterial growth remain enigmatic. Here we show that Arabidopsis thaliana secreted aspartic protease 1 and 2 (SAP1 and SAP2) cleave the evolutionarily conserved bacterial protein MucD to redundantly inhibit the growth of the bacterial pathogen Pseudomonas syringae. Antibacterial activity of SAP1 requires its protease activity in planta and in vitro. Plants overexpressing SAP1 exhibit enhanced MucD cleavage and resistance but incur no penalties in growth and reproduction, while sap1 sap2 double mutant plants exhibit compromised MucD cleavage and resistance against P. syringae. P. syringae lacking mucD shows compromised growth in planta and in vitro. Notably, growth of ΔmucD complemented with the non-cleavable MucDF106Y is not affected by SAP activity in planta and in vitro. Our findings identify the genetic factors and biochemical process underlying an antibacterial mechanism in plants.
Arbitrary waveform AC line filtering applicable to hundreds of volts based on aqueous electrochemical capacitors
Authors: Wu Mingmao , Chi Fengyao , Geng Hongya , Ma Hongyun , Zhang Miao , Gao Tiantian , Li Chun , Qu Liangti 
Published: June 2019

AbstractFiltering capacitor is a necessary component in the modern electronic circuit. Traditional filtering capacitor is often limited by its bulky and rigid configuration and narrow workable scope of applications. Here, an aqueous hybrid electrochemical capacitor is developed for alternating current line filtering with an applicable wide frequency range from 1 to 10,000 Hz. This capacitor possesses an areal specific energy density of 438 μF V2 cm−2 at 120 Hz, which to the best of our knowledge is record high among aqueous electrochemical capacitors reported so far. It can convert arbitrary alternating current waveforms and even noises to straight signals. After integration of capacitor units, a workable voltage up to hundreds of volts (e.g., 200 V) could be achieved without sacrificing its filtering capability. The integrated features of wide frequency range and high workable voltage for this capacitor present promise for multi-scenario and applicable filtering capacitors of practical importance.
Creating fluorescent quantum defects in carbon nanotubes using hypochlorite and light
Authors: Lin Ching-Wei , Bachilo Sergei M. , Zheng Yu , Tsedev Uyanga , Huang Shengnan , Weisman R. Bruce , Belcher Angela M. 
Published: June 2019

AbstractCovalent doping of single-walled carbon nanotubes (SWCNTs) can modify their optical properties, enabling applications as single-photon emitters and bio-imaging agents. We report here a simple, quick, and controllable method for preparing oxygen-doped SWCNTs with desirable emission spectra. Aqueous nanotube dispersions are treated at room temperature with NaClO (bleach) and then UV-irradiated for less than one minute to achieve optimized O-doping. The doping efficiency is controlled by varying surfactant concentration and type, NaClO concentration, and irradiation dose. Photochemical action spectra indicate that doping involves reaction of SWCNT sidewalls with oxygen atoms formed by photolysis of ClO− ions. Variance spectroscopy of products reveals that most individual nanotubes in optimally treated samples show both pristine and doped emission. A continuous flow reactor is described that allows efficient preparation of milligram quantities of O-doped SWCNTs. Finally, we demonstrate a bio-imaging application that gives high contrast short-wavelength infrared fluorescence images of vasculature and lymphatic structures in mice injected with only ~100 ng of the doped nanotubes.
Mathematical Analysis of a Modified Closed-Form Formula for Design a Uniform Leaky-Wave Antenna With Ultra-Low SLL
Authors: Kiani A. , Geran F. , Hashemi S. M. , Forooraghi K. 
Published: June 2019

AbstractStraight long slots have high side-lobes in the far-field amplitude patterns, which reduces their use as high-performance antennas. To reduce these side-lobes, a long slot may be tapered to produce the desired radiation patterns. The theory of control of the aperture distribution to reduce side-lobes has been already reported in some works and well known for already some decades. It is, however, shown in this paper that it may not be good enough to achieve ultra-low side lobes. The theory to analyze and design tapered leaky-wave antennas is described in this paper. Since it is very challenging to achieve a mathematical equation in this regard, some parameters will be calculated using simulation in the first step and the shape of the antenna field is obtained based on these parameters. In the next step, a differential equation is derived for the first step parameters. The solution of this differential equation which is the main motivation of this paper will be expressed in three ways where each part is more accurate than the previous one. According to the measurement results, the structure has a side-lobe level more than −45 dB.
Principles and development of collagen-mediated tissue fusion induced by laser irradiation
Authors: Sasaki Shun , Ikeda Tetsuo , Okihara Shin-ichiro , Nishimura Shotaro , Nakadate Ryu , Saeki Hiroshi , Oki Eiji , Mori Masaki , Hashizume Makoto , Maehara Yoshihiko 
Published: June 2019

AbstractThe mechanism underlying tissue fusion mediated by laser irradiation remains unclear. We clarify the mechanisms underlying laser-mediated tissue fusion using a novel model. Microscopic examinations of morphological changes within the adventitia of a bovine carotid artery and a collagen sheet prepared from bovine dermis showed collagen fibril bundle loosening and collagen fibre swelling following heating at 46 °C. An incised bovine carotid artery covered with a collagen sheet to which pressure and laser heat of 40 °C–52 °C were applied created a structure that was pressure resistant to >300 mmHg. Microscopic analyses of the irradiation site showed collagen fibril interdigitation. Hence, low-temperature laser-mediated tissue fusion causes collagen fibril bundles to loosen and swell, and crimping causes the fibres to intertwine. As the temperature declines, the loosened and swollen fibrils and fibres tighten, and collagen fibre interdigitation is completed. This technology could be applied to fuse tissues during surgery.