bluuebunny/crossref_metadata_2025_split huggingface dataset:
Galewone, an Anti-Fibrotic Polyketide from Daldinia eschscholzii with an Undescribed Carbon Skeleton
Authors: Zhang Ai Hua , Jiang Nan , Wang Xing Qi , Tan Ren Xiang 
Published: October 2019

AbstractA novel polyphenolic natural product, galewone, with undescribed carbon skeleton, was isolated as a racemate from the culture of Daldinia eschscholzii IFB-TL01, a fungus obtained from the mantis (Tenodera aridifolia) gut. The galewone structure was elucidated by a combination of MS and NMR spectra, and substantiated by X-ray crystallographic diffraction. The absolute stereochemistry of each galewone enantiomers was determined by the CD spectrum. In compliance of the structural similarities, galewone might be the shunt products of the dalesconol biosynthetic pathway. Both (−)- and ( + )-galewones were evaluated to be anti-fibrotic against activated hepatic stellate cell line, CFSC-8B, with the IC50 values being 3.73 ± 0.21 and 10.10 ± 0.41 μM, respectively. Thus, galewone may serve as a starting molecule for the discovery of new anti-fibrotic drug.
Genotyping-by-sequencing based QTL mapping for rice grain yield under reproductive stage drought stress tolerance
Authors: Yadav Shailesh , Sandhu Nitika , Singh Vikas Kumar , Catolos Margaret , Kumar Arvind 
Published: October 2019

AbstractQTLs for rice grain yield under reproductive stage drought stress (qDTY) identified earlier with low density markers have shown linkage drag and need to be fine mapped before their utilization in breeding programs. In this study, genotyping-by-sequencing (GBS) based high-density linkage map of rice was developed using two BC1F3 mapping populations namely Swarna*2/Dular (3929 SNPs covering 1454.68 cM) and IR11N121*2/Aus196 (1191 SNPs covering 1399.68 cM) with average marker density of 0.37 cM to 1.18 cM respectively. In total, six qDTY QTLs including three consistent effect QTLs were identified in Swarna*2/Dular while eight qDTY QTLs including two consistent effect QTLs were identified in IR11N121*2/Aus 196 mapping population. Comparative analysis revealed four stable and novel QTLs (qDTY2.4, qDTY3.3, qDTY6.3, and qDTY11.2) which explained 8.62 to 14.92% PVE. However, one of the identified stable grain yield QTL qDTY1.1 in both the populations was located nearly at the same physical position of an earlier mapped major qDTY QTL. Further, the effect of the identified qDTY1.1 was validated in a subset of lines derived from five mapping populations confirming robustness of qDTY1.1 across various genetic backgrounds/seasons. The study successfully identified stable grain yield QTLs free from undesirable linkages of tall plant height/early maturity utilizing high density linkage maps.
Bioinspired DNA Origami Quasi-Yagi Helical Antenna with Beam Direction and Beamwidth Switching Capability
Authors: Shah Syed Imran Hussain , Lim Sungjoon 
Published: October 2019

AbstractWe propose a bioinspired origami quasi-Yagi helical antenna with beam direction and beamwidth switching capability based on transformable DNA origami structure. Each DNA molecule consists of a double helical chain, and its length can be transformed by folding and unfolding. When three transformable origami DNA structures are applied to the quasi-Yagi helical antenna, beam direction and beamwidth can be controlled by folding and unfolding the origami DNA. The transformable DNA structures act as driven, director and reflector elements. The proposed DNA origami antenna provides four beam direction switching states (three states with narrow beamwidth and one state with wide beamwidth) at fixed frequency of 1.9 GHz. For example, the main beam direction of the proposed antenna can be steered to −30°, 0°, +30° and −40° for states 1, 2, 3 and 4, respectively. State 4 provides a 3-dB wider beamwidth of 104°, whereas the beamwidth of other states is narrower than 64°. The proposed concept is numerically and experimentally demonstrated.
A machine learning based delta-radiomics process for early prediction of treatment response of pancreatic cancer
Authors: Nasief Haidy , Zheng Cheng , Schott Diane , Hall William , Tsai Susan , Erickson Beth , Allen Li X. 
Published: October 2019

AbstractChanges of radiomic features over time in longitudinal images, delta radiomics, can potentially be used as a biomarker to predict treatment response. This study aims to develop a delta-radiomic process based on machine learning by (1) acquiring and registering longitudinal images, (2) segmenting and populating regions of interest (ROIs), (3) extracting radiomic features and calculating their changes (delta-radiomic features, DRFs), (4) reducing feature space and determining candidate DRFs showing treatment-induced changes, and (5) creating outcome prediction models using machine learning. This process was demonstrated by retrospectively analyzing daily non-contrast CTs acquired during routine CT-guided-chemoradiation therapy for 90 pancreatic cancer patients. A total of 2520 CT sets (28-daily-fractions-per-patient) along with their pathological response were analyzed. Over 1300 radiomic features were extracted from the segmented ROIs. Highly correlated DRFs were ruled out using Spearman correlations. Correlation between the selected DRFs and pathological response was established using linear-regression-models. T test and linear-mixed-effects-models were used to determine which DRFs changed significantly compared with first fraction. A Bayesian-regularization-neural-network was used to build a response prediction model. The model was trained using 50 patients and leave-one-out-cross-validation. Performance was judged using the area-under-ROC-curve. External independent validation was done using data from the remaining 40 patients. The results show that 13 DRFs passed the tests and demonstrated significant changes following 2–4 weeks of treatment. The best performing combination differentiating good versus bad responders (CV-AUC = 0.94) was obtained using normalized-entropy-to-standard-deviation-difference-(NESTD), kurtosis, and coarseness. With further studies using larger data sets, delta radiomics may develop into a biomarker for early prediction of treatment response.
On the use of CdSe scintillating nanoplatelets as time taggers for high-energy gamma detection
Authors: Turtos R. M. , Gundacker S. , Omelkov S. , Mahler B. , Khan A. H. , Saaring J. , Meng Z. , Vasil’ev A. , Dujardin C. , Kirm M. , Moreels I. , Auffray E. , Lecoq P. 
Published: October 2019

AbstractThe technological challenge imposed by the time resolution essential to achieve real-time molecular imaging calls for a new generation of ultrafast detectors. In this contribution, we demonstrate that CdSe-based semiconductor nanoplatelets can be combined with standard scintillator technology to achieve 80 ps coincidence time resolution on a hybrid functional pixel. This result contrasts with the fact that the overall detector light output is considerably affected by the loss of index-light-guiding. Here, we exploit the principle of 511 keV energy sharing between a high-Z, high stopping power bulk scintillator, and a nano-scintillator with sub-1 ns radiative recombination times, aiming at a breakthrough in the combined energy and time resolution performance. This proof-of-concept test opens the way to the design and study of larger size sensors using thin nanocomposite layers able to perform as efficient time taggers in a sampling detector geometry of new generation.
3D mapping reveals network-specific amyloid progression and subcortical susceptibility in mice
Authors: Gail Canter Rebecca , Huang Wen-Chin , Choi Heejin , Wang Jun , Ashley Watson Lauren , Yao Christine G. , Abdurrob Fatema , Bousleiman Stephanie M. , Young Jennie Z. , Bennett David A. , Delalle Ivana , Chung Kwanghun , Tsai Li-Huei 
Published: October 2019

AbstractAlzheimer’s disease (AD) is a progressive, neurodegenerative dementia with no cure. Prominent hypotheses suggest accumulation of beta-amyloid (Aβ) contributes to neurodegeneration and memory loss, however identifying brain regions with early susceptibility to Aβ remains elusive. Using SWITCH to immunolabel intact brain, we created a spatiotemporal map of Aβ deposition in the 5XFAD mouse. We report that subcortical memory structures show primary susceptibility to Aβ and that aggregates develop in increasingly complex networks with age. The densest early Aβ occurs in the mammillary body, septum, and subiculum- core regions of the Papez memory circuit. Previously, early mammillary body dysfunction in AD had not been established. We also show that Aβ in the mammillary body correlates with neuronal hyper-excitability and that modulation using a pharmacogenetic approach reduces Aβ deposition. Our data demonstrate large-tissue volume processing techniques can enhance biological discovery and suggest that subcortical susceptibility may underlie early brain alterations in AD.
Digital phenotyping by consumer wearables identifies sleep-associated markers of cardiovascular disease risk and biological aging
Authors: Teo Jing Xian , Davila Sonia , Yang Chengxi , Hii An An , Pua Chee Jian , Yap Jonathan , Tan Swee Yaw , Sahlén Anders , Chin Calvin Woon-Loong , Teh Bin Tean , Rozen Steven G. , Cook Stuart Alexander , Yeo Khung Keong , Tan Patrick , Lim Weng Khong 
Published: October 2019

AbstractSleep is associated with various health outcomes. Despite their growing adoption, the potential for consumer wearables to contribute sleep metrics to sleep-related biomedical research remains largely uncharacterized. Here we analyzed sleep tracking data, along with questionnaire responses and multi-modal phenotypic data generated from 482 normal volunteers. First, we compared wearable-derived and self-reported sleep metrics, particularly total sleep time (TST) and sleep efficiency (SE). We then identified demographic, socioeconomic and lifestyle factors associated with wearable-derived TST; they included age, gender, occupation and alcohol consumption. Multi-modal phenotypic data analysis showed that wearable-derived TST and SE were associated with cardiovascular disease risk markers such as body mass index and waist circumference, whereas self-reported measures were not. Using wearable-derived TST, we showed that insufficient sleep was associated with premature telomere attrition. Our study highlights the potential for sleep metrics from consumer wearables to provide novel insights into data generated from population cohort studies.
Quantum spacetime on a quantum simulator
Authors: Li Keren , Li Youning , Han Muxin , Lu Sirui , Zhou Jie , Ruan Dong , Long Guilu , Wan Yidun , Lu Dawei , Zeng Bei , Laflamme Raymond 
Published: October 2019

AbstractQuantum simulation has shown its irreplaceable role in many fields, where it is difficult for classical computers to do much. On a four-qubit Nuclear Magnetic Resonance (NMR) quantum simulator, we experimentally simulate the spin-network states by simulating quantum spacetime tetrahedra. The fidelities of our experimentally prepared quantum tetrahedra are all above 95%. We then use the quantum tetradedra prepared by the Nuclear Magnetic Resonance to simulate a spinfoam vertex amplitude, which displays the local dynamics of quantum spacetime. By measuring the geometric properties on the corresponding quantum tetrahedra and simulating their interaction, our experiment serves as a basic module that represents the Feynman diagram vertex in the spinfoam formulation of Loop Quantum Gravity(LQG). This is an initial attempt to study LQG by quantum information processing.
Reconfigurable flows and defect landscape of confined active nematics
Authors: Hardoüin Jérôme , Hughes Rian , Doostmohammadi Amin , Laurent Justine , Lopez-Leon Teresa , Yeomans Julia M. , Ignés-Mullol Jordi , Sagués Francesc 
Published: October 2019

AbstractThe physics of active liquid crystals is mostly governed by the interplay between elastic forces that align their constituents, and active stresses that destabilize the order with constant nucleation of topological defects and chaotic flows. The average distance between defects, also called active length scale, depends on the competition between these forces. Here, in experiments with the microtubule/kinesin active nematic system, we show that the intrinsic active length scale loses its relevance under strong lateral confinement. Transitions are observed from chaotic to vortex lattices and defect-free unidirectional flows. Defects, which determine the active flow behaviour, are created and annihilated on the channel walls rather than in the bulk, and acquire a strong orientational order in narrow channels. Their nucleation is governed by an instability whose wavelength is effectively screened by the channel width. These results are recovered in simulations, and the comparison highlights the role of boundary conditions.
Ground-based optical transmission spectrum of the hot Jupiter HAT-P-1b
Authors: Todorov Kamen O. , Désert Jean-Michel , Huitson Catherine M. , Bean Jacob L. , Panwar Vatsal , de Matos Filipe , Stevenson Kevin B. , Fortney Jonathan J. , Bergmann Marcel 
Published: October 2019

Context. Time-series spectrophotometric studies of exoplanets during transit using ground-based facilities are a promising approach to characterize their atmospheric compositions.
Aims. We aim to investigate the transit spectrum of the hot Jupiter HAT-P-1b. We compare our results to those obtained at similar wavelengths by previous space-based observations.
Methods. We observed two transits of HAT-P-1b with the Gemini Multi-Object Spectrograph (GMOS) instrument on the Gemini North telescope using two instrument modes covering the 320–800 and 520–950 nm wavelength ranges. We used time-series spectrophotometry to construct transit light curves in individual wavelength bins and measure the transit depths in each bin. We accounted for systematic effects. We addressed potential photometric variability due to magnetic spots in the planet’s host star with long-term photometric monitoring.
Results. We find that the resulting transit spectrum is consistent with previous Hubble Space Telescope (HST) observations. We compare our observations to transit spectroscopy models that marginally favor a clear atmosphere. However, the observations are also consistent with a flat spectrum, indicating high-altitude clouds. We do not detect the Na resonance absorption line (589 nm), and our observations do not have sufficient precision to study the resonance line of K at 770 nm.
Conclusions. We show that even a single Gemini/GMOS transit can provide constraining power on the properties of the atmosphere of HAT-P-1b to a level comparable to that of HST transit studies in the optical when the observing conditions and target and reference star combination are suitable. Our 520–950 nm observations reach a precision comparable to that of HST transit spectra in a similar wavelength range of the same hot Jupiter, HAT-P-1b. However, our GMOS transit between 320–800 nm suffers from strong systematic effects and yields larger uncertainties.
A comprehensive study of NGC 2345, a young open cluster with a low metallicity
Authors: Alonso-Santiago J. , Negueruela I. , Marco A. , Tabernero H. M. , González-Fernández C. , Castro N. 
Published: October 2019

Context.NGC 2345 is a young open cluster that hosts seven blue and red supergiants, low metallicity, and a high fraction of Be stars, which makes it a privileged laboratory to study stellar evolution.Aims.We aim to improve the determination of the cluster parameters and study the Be phenomenon. Our objective is also to characterise the seven evolved stars found in NGC 2345 by deriving their atmospheric parameters and chemical abundances.Methods.We performed a complete analysis combining for the first timeubvyphotometry with spectroscopy as well as theGaiaData Release 2. We obtained spectra with classification purposes for 76 stars and high-resolution spectroscopy for an in-depth analysis of the blue and red evolved stars.Results.We identify a new red supergiant and 145 B-type likely members within a radius of 18.7 ± 1.2 arcmin, which implies an initial mass,Mcl ≈ 5200 M⊙. We find a distance of 2.5 ± 0.2 kpc for NGC 2345, placing it atRGC = 10.2 ± 0.2 kpc. Isochrone fitting supports an age of 56 ± 13 Ma, implying masses around 6.5M⊙for the supergiants. A high fraction of Be stars (≈10%) is found. From the spectral analysis we estimate an averagevrad = +58.6 ± 0.5 km s−1and a low metallicity, [Fe/H] = −0.28 ± 0.07, for the cluster. We also determine chemical abundances for Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the evolved stars. The chemical composition of the cluster is consistent with that of the Galactic thin disc. One of the K supergiants, S50, is a Li-rich star, presenting anA(Li) ≈ 2.1. An overabundance of Ba is found, supporting the enhanceds-process.Conclusions.NGC 2345 has a low metallicity for its Galactocentric distance, which is comparable to typical Large Magellanic Cloud stars. It is massive enough to serve as a test bed for theoretical evolutionary models for massive intermediate-mass stars.
Hemispheric injection of magnetic helicity by surface flux transport
Authors: Hawkes G. , Yeates A. R. 
Published: October 2019

Aims. We estimate the injection of relative magnetic helicity into the solar atmosphere by surface flux transport over 27 solar cycles (1700–2009).
Methods. We determine the radial magnetic field evolution using two separate surface flux transport models: one driven by magnetogram inputs and another by statistical active region insertion guided by the sunspot number record. The injection of relative magnetic helicity is then computed from this radial magnetic field together with the known electric field in the flux transport models.
Results. Neglecting flux emergence, solar rotation is the dominant contributor to the helicity injection. At high latitudes, the injection is always negative/positive in the northern/southern hemisphere, while at low latitudes the injection tends to have the opposite sign when integrated over the full solar cycle. The overall helicity injection in a given solar cycle depends on the balance between these two contributions. This net injected helicity correlates well with the end-of-cycle axial dipole moment.
MoMo: a new empirical model of the Mars ionospheric total electron content based on Mars Express MARSIS data
Authors: Bergeot Nicolas , Witasse Olivier , Le Maistre Sébastien , Blelly Pierre-Louis , Kofman Wlodek , Peter Kerstin , Dehant Véronique , Chevalier Jean-Marie 
Published: October 2019

Aims: Several scientific landers and rovers have reached the Martian surface since the 1970s. Communication between the asset (i.e., lander or rover) and Mars orbiters or Earth antennas uses radio signals in UHF to X-band frequencies passing through the Mars’ ionosphere. It is consequently necessary to take into account electron density variation in the Mars’ ionosphere to correct the refraction of the signal transmitted. Methods: We developed a new empirical model of the Mars’ ionosphere called MoMo. It is based on the large database of Total Electron Content (TEC) derived from the subsurface mode of the Mars Express MARSIS radar. The model provides vertical TEC as a function of solar zenith angle, solar activity, solar longitude and location. For validation, the model is compared with Mars Express radio occultation data as well as with the numerical model IPIM (IRAP Plasmasphere-Ionosphere Model). Results: We discussed the output of the model in terms of climatology behaviour of the Mars’ ionosphere. The output of MoMo is then uses to quantify the impact of the Martian ionosphere for radio-science experiments. From our results, the effect is of the order of 10−3 mm s−1 in Doppler observables especially around sunrise and sunset. Consequently, this new model could be used to support the data analysis of any radio-science experiment and especially for present InSight RISE and futur ExoMars LARA instruments aiming at better understand the deep-interior of Mars.
Diagnosis and Treatment of Candidemia in the Intensive Care Unit
Authors: Bassetti Matteo , Giacobbe Daniele R. , Vena Antonio , Wolff Michel 
Published: October 2019

AbstractCandidemia is the fourth most frequent health care-associated bloodstream infection, and the most frequent severe fungal infection developing in critically ill patients in intensive care units (ICUs). Diagnosis of candidemia in ICU patients is a complex task made of both early and late assessments involving both conventional diagnostic methods and novel rapid tests. Management strategies to optimize treatment of candidemia can be challenging and include starting early adequate therapy, use of an adequate dose and duration of therapy, de-escalating treatment whenever possible, and early discontinuation of useless antifungals in those with no definitive diagnosis of fungal infection. Herein, we will discuss recent epidemiological data on candidemia in ICUs and current diagnostic techniques before concentrating on antifungal treatments.
A Practical Approach to Clinical Antibiotic Stewardship in the ICU Patient with Severe Infection
Authors: Fierens Jan , Depuydt Pieter O. , De Waele Jan J. 
Published: October 2019

AbstractPatients with severe infections are often treated with multiple courses of antibiotics in the intensive care unit (ICU), making the ICU a true antibiotic hotspot. The increasing incidence of multidrug resistance worldwide emphasizes the need for continued efforts in developing and implementing antibiotic stewardship programs. Using a pragmatic approach for the bedside clinical team, this review will highlight different key moments for antibiotic decision making throughout the course of the antibiotic treatment in patients with severe infections. We will focus especially on the importance of adequate empirical therapy, source control in infections, assessment of immune status, and two separate antibiotic time-out moments early in the course, as well as the moment of stopping antibiotics. Additionally, the importance of a team-based approach and clinical decision support systems will be highlighted.
Prevention of Intensive Care Unit-Acquired Pneumonia
Authors: Klompas Michael 
Published: October 2019

AbstractIntensive care unit (ICU) acquired pneumonia is one of the most common and morbid health care-associated infections. Despite decades of work developing and testing prevention strategies, ICU-acquired pneumonia remains stubbornly pervasive. Pneumonia prevention studies are difficult to interpret because all are at risk of bias due to the subjectivity and poor specificity of pneumonia definitions. Interventions associated with improvements in objective outcomes in addition to pneumonia, such as length of stay or mortality, should therefore be prioritized. Avoiding intubation, minimizing sedation, implementing early extubation strategies, and mobilizing patients do appear to improve some of these objective outcomes. Many of our other assumptions about how best to prevent ICU-acquired pneumonia, however, have recently been challenged. Elevating the head of the bed is supported by very little randomized trial data. Early reports suggested that subglottic secretion drainage may decrease time to extubation and ICU length of stay, but more recent analyses refute these findings. Novel endotracheal tube cuff designs do not clearly lower pneumonia rates. A large randomized trial of selective digestive decontamination in ICUs with high baseline rates of antimicrobial resistance did not identify any benefit. Oral care with chlorhexidine may increase mortality risk and stress ulcer prophylaxis may facilitate pneumonia. Early data on probiotics suggest a possible effect but there is no clear signal yet that they shorten duration of mechanical ventilation or lower mortality. Ventilator bundles on balance do appear to be beneficial but it is not clear which components are most important nor how best to implement them. This article will review recent studies that have challenged, refined, or complicated our understanding of how best to prevent ICU-acquired pneumonia.