bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pheophorbide A from Gelidium amansii improves postprandial hyperglycemia in diabetic mice through α‐glucosidase inhibition
Authors: Kim Min Jung , Kim Hak Ju , Han Ji Sook 
Published: January 2019

This study was designed to determine the inhibitory effects of pheophorbide A on carbohydrate digesting enzymes and its ability to improve postprandial hyperglycemia in streptozotocin (STZ)‐induced diabetic mice. Pheophorbide A caused noticeable inhibitory effects on α‐glucosidase and α‐amylase, with half‐maximal inhibitory concentrations (IC50) of 80.65 ± 5.90 and 76.48 ± 6.31 μM, respectively. The pheophorbide‐mediated inhibition of α‐glucosidase and α‐amylase was significantly more effective than that of the positive control, acarbose. The increase in postprandial blood glucose levels was more significantly suppressed in the pheophorbide A group than in the control group of STZ‐induced diabetic mice. In addition, the area under the curve was decreased by pheophorbide A intake in STZ‐induced diabetic mice. Our results suggested that pheophorbide A may help to improve postprandial hyperglycemia by inhibiting the activity of carbohydrate digesting enzymes.
Regioselective Synthesis of Functionalized 1,3‐Thiazine‐4‐ones via Multicomponent Click Reaction Approach
Authors: Hussen Abdulkadir Shube , Monga Aparna , Sharma Anuj 
Published: January 2019

AbstractHerein, we disclose a synthetic strategy for the preparation of functionalized thiazinones under exceptionally ambient condition via domino multicomponent click reaction. The protocol utilizes readily available starting materials: phenylisothiocyanates, hydrazine monohydrate and diethyl but‐2‐ynedioate or dimethyl but‐2‐ynedioate. The reaction condition merely requires mixing of substrates at room temperature without using any catalyst and/or solvent.
Structural Coloration with Nonclose‐Packed Array of Bidisperse Colloidal Particles
Authors: Lee Gun Ho , Kim Jong Bin , Choi Tae Min , Lee Jung Min , Kim Shin‐Hyun 
Published: January 2019

AbstractColloidal crystals and glasses have their own photonic effects. Colloidal crystals show high reflectivity at narrowband, whereas colloidal glasses show low reflectivity at broadband. To compromise the opposite optical properties, a simple means is suggested to control the colloidal arrangement between crystal and glass by employing two different sizes of silica particles with repulsive interparticle potential. Monodisperse silica particles with repulsive potential spontaneously form crystalline structure at volume fraction far below 0.74. When two different sizes of silica particles coexist, the arrangement of silica particles is significantly influenced by two parameters: size contrast and mixing ratio. When the size contrast is small, a long‐range order is partially conserved in the entire mixing ratio, resulting in a pronounced reflectance peak and brilliant structural color. When the size contrast is large, the long‐range order is rapidly reduced along with mixing ratio. Nevertheless, a short‐range order survives, which causes low reflectivity at a broad wavelength, developing faint structural colors. These findings offer an insight into controlling the colloidal arrangements and provide a simple way to tune the optical property of colloidal arrays for structural coloration.
Phosphorescent Pt(II) Emitters for OLEDs: From Triarylboron‐Functionalized Bidentate Complexes to Compounds with Macrocyclic Chelating Ligands
Authors: Wang Xiang , Wang Suning 
Published: January 2019

AbstractThe development of organic light‐emitting diodes (OLEDs) has attracted enormous research efforts from both academia and industry in the past decades and tremendous progress has been made. However, the low operation lifetime of the blue phosphorescent OLEDs remains as one of the greatest bottlenecks limiting further applications of OLEDs. To address this problem, design and synthesis of triplet emitters with high phosphorescence quantum yield (ΦP) and adequate thermal, chemical, electrical and ultraviolet (UV) stabilities are vital. This review summarizes the progress we made on the development of efficient and robust phosphorescent emitters based on cyclometalated Pt(II) compounds, particularly the ones with blue emission, starting from complexes with triarylboron‐functionalized bidentate ligand to molecules incorporating tetradentate and macrocyclic ligands, with emphasis on their structure‐property relationships.
Type IIA flux vacua with mobile D6-branes
Authors: Escobar Dagoberto , Marchesano Fernando , Staessens Wieland 
Published: January 2019

AbstractWe analyse type IIA Calabi-Yau orientifolds with background fluxes and D6-branes. The presence of D6-brane deformation moduli redefines the 4d dilaton and complex structure fields and complicates the analysis of such vacua in terms of the effective Kähler potential and superpotential. One may however formulate the F-term scalar potential as a bilinear form on the flux-axion polynomialsρAinvariant under the discrete shift symmetries of the 4d effective theory. We express the conditions for Minkoswki and AdS flux vacua in terms of such polynomials, which allow to extend the analysis to include vacua with mobile D6-branes. We find a new, more general class of$$ \mathcal{N}=0 $$N=0Minkowski vacua, which nevertheless present a fairly simple structure of (contravariant) F-terms. We compute the soft-term spectrum for chiral models of intersecting D6-branes in such vacua, finding a quite universal pattern.
Weak convergence of the number of vertices at intermediate levels of random recursive trees
Authors: Iksanov Alexander , Kabluchko Zakhar 
Published: January 2019

Abstract
Let Xn(k) be the number of vertices at level k in a random recursive tree with n+1 vertices. We are interested in the asymptotic behavior of Xn(k) for intermediate levels k=kn satisfying kn→∞ and kn=o(logn) as n→∞. In particular, we prove weak convergence of finite-dimensional distributions for the process (Xn ([knu]))u>0, properly normalized and centered, as n→∞. The limit is a centered Gaussian process with covariance (u,v)↦(u+v)−1. One-dimensional distributional convergence of Xn(kn), properly normalized and centered, was obtained with the help of analytic tools by Fuchs et al. (2006). In contrast, our proofs, which are probabilistic in nature, exploit a connection of our model with certain Crump–Mode–Jagers branching processes.
Learning leadership? Elite Ugandan students and late colonial politics
Authors: Summers Carol 
Published: January 2019

AbstractIn Uganda, teaching and learning were important metaphors for colonial rule, suggesting a benign protectorate under Britain's guidance. Ugandans, though, repurposed images of teaching, studying and educational sponsorship. Drawing on indigenous ideas about effective education as a sort of experiential education in leadership, they perceived student activism as a resource for a new political and social system. Articulate Ugandans sought elite British education as a weapon. Others emphasized the harsh competitiveness of Uganda's elite schools as the basis for new class solidarities. And educated men saw their ownership of schools as a foundation on which to build political followings as they worked to guide the country. Student activism in Uganda emphasized educated Ugandans’ individual and collective practice in power and leadership.
Dairy foods and bone health throughout the lifespan: a critical appraisal of the evidence
Authors: Iuliano Sandra , Hill Tom R. 
Published: January 2019

AbstractThe consumption of high-Ca, high-protein dairy foods (i.e. milk, cheese, yogurt) is advocated for bone health across the lifespan to reduce the risk of low-trauma fractures. However, to date, the anti-fracture efficacy of dairy food consumption has not been demonstrated in randomised controlled trials but inferred from cross-sectional and prospective studies. The anti-fracture efficacy of dairy food consumption is plausible, but testing this requires a robust study design to ensure outcomes are suitably answering this important public health question. The evidence of skeletal benefits of dairy food consumption is equivocal, not because it may not be efficacious but because the study design and execution are often inadequate. The key issues are compliance with dietary intervention, dropouts, sample sizes and most importantly lack of deficiency before intervention. Without careful appraisal of the design and execution of available studies, precarious interpretations of outcomes may be made from these poorly designed or executed studies, without consideration of how study design may be improved. Dairy food interventions in children are further hampered by heterogeneity in growth: in particular sex and maturity-related differences in the magnitude, timing, location and surface-specific site of bone accrual. Outcomes of studies combining children of different sexes and maturity status may be masked or exaggerated by these differences in growth, so inaccurate conclusions are drawn from results. Until these critical issues in study design are considered in future dairy food interventions, the anti-fracture efficacy of dairy food consumption may remain unknown and continue to be based on conjecture.
‘Situational Analysis’ and Economics: an attempt at clarification
Authors: Palacio-Vera Alfonso 
Published: January 2019

AbstractPopper’s ‘Situational Analysis’ (SA) constitutes his methodological proposal for the social sciences. We claim that the two hallmarks of SA are: (i) that scientists assume they possess a ‘wider’ view of the problem-situation than actors do, and (ii) use the model as an ideal ‘benchmark’ scenario to identify thedeviationof actors’ actual behaviour from the former. We argue that SA is not a generalization of the neoclassical theory of individual behaviour but captures instead the methodology adopted by modern behavioural economists. Last, we argue that SA highlights a way of acquiring knowledge that has gone unnoticed in the literature.
Magnitude of Earthquakes Controls the Size Distribution of Their Triggered Events
Authors: Nandan Shyam , Ouillon Guy , Sornette Didier 
Published: January 2019

AbstractThe driving concept behind one of the most successful statistical forecasting models, the Epidemic Type Aftershock Sequence (ETAS) model, has been that the seismicity is driven by spontaneously occurring background earthquakes that cascade into multitudes of triggered earthquakes. In nearly all generalizations of the ETAS model, the magnitudes of the background and the triggered earthquakes are assumed to follow Gutenberg‐Richter law with the same exponent (βvalue). Furthermore, the magnitudes of the triggered earthquakes are always assumed to be independent of the magnitude of the triggering earthquake. Using an expectation maximization algorithm applied to the Californian earthquake catalog, we show that the distribution of earthquake magnitudes exhibits three distinctβvalues:βbfor background events andβa − δandβa + δ, respectively, for triggered events below and above the magnitude of the triggering earthquake; the two last values express a correlation between the magnitudes of triggered events with that of the triggering earthquake, a feature so far absent in all proposed operational generalizations of the ETAS model. The ETAS model incorporating this kinked magnitude distribution provides by far the best description of seismic catalogs and could thus have the best forecasting potential. We speculate that the kinked magnitude distribution may result from the system tending to restore the symmetry of the regional displacement gradient tensor that has been broken by the initiating event. The general emerging concept could be that while the background events occur primarily to accommodate the symmetric stress tensor at the boundaries of the system, the triggered earthquakes are quasi‐Goldstone fluctuations of a self‐organized critical deformation state.
Numerical Study of Shear Stress Distribution Over Sand Ripples Under Terrestrial and Martian Conditions
Authors: Siminovich A. , Elperin T. , Katra I. , Kok J. F. , Sullivan R. , Silvestro S. , Yizhaq H. 
Published: January 2019

AbstractRipples occur on Earth and Mars in a range of sizes. From terrestrial studies, ripple size is known to depend on grain‐size frequency, wind duration, wind strength (including stronger winds that can flatten ripples), and fundamental environmental factors that differ between the two planets. Here we use computational fluid dynamics (CFD) experiments to model boundary layer shear stresses applied to aeolian ripple surfaces, to investigate how these stresses might differ between Earth and Mars. CFD experiments used ANSYS Fluent, with inlet wind speeds of 10 and 15 m/s for both planetary environments. Ripple profiles for Earth and Mars were developed using saltation and reptation properties modeled by the numerical saltation model COMSALT (Kok & Renno, 2009, https://doi.org.10.1029/2009JDO11702) to develop ripple profiles using the numerical technique of Yizhaq et al. (2004, https://doi.org.10.1016/j.physd.2004.03.015). Although the CFD experiments using these inputs could not include the effects of a saltation cloud, results are robust enough to indicate clearly that for similar modeled wind speeds on Earth and Mars, boundary layer shear stress applied to ripple surfaces is greater on Earth under conditions for which sand transport is expected. These results indicate that ripples can grow larger on Mars than on Earth, because for typical Martian wind speeds the shear velocity at the ripple crests is below the fluid threshold.
The ketogenic diet influences taxonomic and functional composition of the gut microbiota in children with severe epilepsy
Authors: Lindefeldt Marie , Eng Alexander , Darban Hamid , Bjerkner Annelie , Zetterström Cecilia K , Allander Tobias , Andersson Björn , Borenstein Elhanan , Dahlin Maria , Prast-Nielsen Stefanie 
Published: January 2019

AbstractThe gut microbiota has been linked to various neurological disorders via the gut–brain axis. Diet influences the composition of the gut microbiota. The ketogenic diet (KD) is a high-fat, adequate-protein, low-carbohydrate diet established for treatment of therapy-resistant epilepsy in children. Its efficacy in reducing seizures has been confirmed, but the mechanisms remain elusive. The diet has also shown positive effects in a wide range of other diseases, including Alzheimer’s, depression, autism, cancer, and type 2 diabetes. We collected fecal samples from 12 children with therapy-resistant epilepsy before starting KD and after 3 months on the diet. Parents did not start KD and served as diet controls. Applying shotgun metagenomic DNA sequencing, both taxonomic and functional profiles were established. Here we report that alpha diversity is not changed significantly during the diet, but differences in both taxonomic and functional composition are detected. Relative abundance of bifidobacteria as well asE. rectaleandDialisteris significantly diminished during the intervention. An increase in relative abundance ofE. coliis observed on KD. Functional analysis revealed changes in 29 SEED subsystems including the reduction of seven pathways involved in carbohydrate metabolism. Decomposition of these shifts indicates that bifidobacteria andEscherichiaare important contributors to the observed functional shifts. As relative abundance of health-promoting, fiber-consuming bacteria becomes less abundant during KD, we raise concern about the effects of the diet on the gut microbiota and overall health. Further studies need to investigate whether these changes are necessary for the therapeutic effect of KD.
Machine learning techniques for state recognition and auto-tuning in quantum dots
Authors: Kalantre Sandesh S. , Zwolak Justyna P. , Ragole Stephen , Wu Xingyao , Zimmerman Neil M. , Stewart M. D. , Taylor Jacob M. 
Published: January 2019

AbstractRecent progress in building large-scale quantum devices for exploring quantum computing and simulation has relied upon effective tools for achieving and maintaining good experimental parameters, i.e., tuning up devices. In many cases, including quantum dot-based architectures, the parameter space grows substantially with the number of qubits, and may become a limit to scalability. Fortunately, machine learning techniques for pattern recognition and image classification, using so-called deep neural networks, have shown surprising successes for computer-aided understanding of complex systems. We propose a new paradigm for fully automated experimental initialization through a closed-loop system relying on machine learning and optimization techniques. We use deep convolutional neural networks to characterize states and charge configurations of semiconductor quantum dot arrays when only measurements of a current−voltage characteristic of transport are available. For simplicity, we model a semiconductor nanowire connected to leads and capacitively coupled to depletion gates using the Thomas−Fermi approximation and Coulomb blockade physics. We then generate labeled training data for the neural networks, and find at least 90 % accuracy for charge and state identification for single and double dots. Using these characterization networks, we can then optimize the parameter space to achieve a desired configuration of the array, a technique we call “auto-tuning”. Finally, we show how such techniques can be implemented in an experimental setting by applying our approach to an experimental dataset, and outline further problems in this domain, from using charge sensing data to extensions to full one- and two-dimensional arrays, that can be tackled with machine learning.
Microplate-based surface area assay for rapid phenotypic antibiotic susceptibility testing
Authors: Flentie Kelly , Spears Benjamin R , Chen Felicia , Purmort Nathan B , DaPonte Kayla , Viveiros Emma , Phelan Nicholas , Krebill Cicely , Flyer Alec N. , Hooper David C , Smalley David L. , Ferraro Mary Jane , Vacic Aleksandar , Stern Eric 
Published: January 2019

AbstractRapid delivery of proper antibiotic therapies to infectious disease patients is essential for improving patient outcomes, decreasing hospital lengths-of-stay, and combating the antibiotic resistance epidemic. Antibiotic stewardship programs are designed to address these issues by coordinating hospital efforts to rapidly deliver the most effective antibiotics for each patient, which requires bacterial identification and antimicrobial susceptibility testing (AST). Despite the clinical need for fast susceptibility testing over a wide range of antibiotics, conventional phenotypic AST requires overnight incubations, and new rapid phenotypic AST platforms restrict the number of antibiotics tested for each patient. Here, we introduce a novel approach to AST based on signal amplification of bacterial surfaces that enables phenotypic AST within 5 hours for non-fastidious bacteria. By binding bacterial surfaces, this novel method allows more accurate measurements of bacterial replication in instances where organisms filament or swell in response to antibiotic exposure. Further, as an endpoint assay performed on standard microplates, this method should enable parallel testing of more antibiotics than is currently possible with available automated systems. This technology has the potential to revolutionize clinical practice by providing rapid and accurate phenotypic AST data for virtually all available antibiotics in a single test.
Circulating GATA2 mRNA is decreased among women destined to develop preeclampsia and may be of endothelial origin
Authors: Whigham Carole-Anne , MacDonald Teresa M. , Walker Susan P. , Pritchard Natasha , Hannan Natalie J. , Cannon Ping , Nguyen Tuong Vi , Hastie Roxanne , Tong Stephen , Kaitu’u-Lino Tu’uhevaha J. 
Published: January 2019

AbstractPreeclampsia is a pregnancy complication associated with elevated placental secretion of anti-angiogenic factors, maternal endothelial dysfunction and organ injury. GATA2 is a transcription factor expressed in the endothelium which regulates vascular homeostasis by controlling transcription of genes and microRNAs, including endothelial miR126. We assessed GATA2 and miR126 in preeclampsia. Whole blood circulating GATA2 mRNA and miR126 expression were significantly decreased in women with established early-onset preeclampsia compared to gestation-matched controls (p = 0.002, p < 0.0001, respectively). Using case-control groups selected from a large prospective cohort, whole blood circulating GATA2 mRNA at both 28 and 36 weeks’ gestation was significantly reduced prior to the clinical diagnosis of preeclampsia (p = 0.012, p = 0.015 respectively). There were no differences in GATA2 mRNA or protein expression in preeclamptic placentas compared to controls, suggesting the placenta is an unlikely source. Inducing endothelial dysfunction in vitro by administering either tumour necrosis factor-α or placenta-conditioned media to endothelial cells, significantly reduced GATA2 mRNA expression (p < 0.0001), suggesting the reduced levels of circulating GATA2 mRNA may be of endothelial origin. Circulating GATA2 mRNA is decreased in women with established preeclampsia and decreased up to 12 weeks preceding onset of disease. Circulating mRNAs of endothelial origin may be a novel source of biomarker discovery for preeclampsia.
Switchable valley splitting by external electric field effect in graphene/CrI3 heterostructures
Authors: Farooq M. Umar , Hong Jisang 
Published: January 2019

AbstractAchieving and controlling valley splitting is a core issue for valleytronics applications. Conventionally, valley splitting was achieved by applying an external magnetic field or structural manipulation. However, this approach is less efficient. Here, we explored single layer and bilayer graphene on CrI3 (g-CrI3 and 2g-CrI3) heterostructures to induce valley splitting. In g-CrI3, we found a valley splitting with the majority gap difference of Δ1↑ − Δ2↑ = 44 meV. Even in 2g-CrI3 system, we also found valley splitting of Δ1↑ − Δ2↑ = 21 meV. Moreover, we also investigated the electric field effect on valley splitting. In both systems, we observed that valley splitting could be switched in the majority spin band. For instance, the sign of gap difference at ±K changed from Δ1↑ > Δ2↑ at zero field to Δ1↑ < Δ2↑ at a small applied electric field of 0.1 V/Å. With further increase of the electric field to 0.2 V/Å, valley splitting disappeared. Thus, we propose that a large value of valley splitting can be achieved and the sign of splitting can also be switched with electric field instead of magnetic field. This feature may be beneficial for designing of valleytronic based information process devices.
Nanoscale mosaicity revealed in peptide microcrystals by scanning electron nanodiffraction
Authors: Gallagher-Jones Marcus , Ophus Colin , Bustillo Karen C. , Boyer David R. , Panova Ouliana , Glynn Calina , Zee Chih-Te , Ciston Jim , Mancia Kevin Canton , Minor Andrew M. , Rodriguez Jose A. 
Published: January 2019

AbstractChanges in lattice structure across sub-regions of protein crystals are challenging to assess when relying on whole crystal measurements. Because of this difficulty, macromolecular structure determination from protein micro and nanocrystals requires assumptions of bulk crystallinity and domain block substructure. Here we map lattice structure across micron size areas of cryogenically preserved three−dimensional peptide crystals using a nano-focused electron beam. This approach produces diffraction from as few as 1500 molecules in a crystal, is sensitive to crystal thickness and three−dimensional lattice orientation. Real-space maps reconstructed from unsupervised classification of diffraction patterns across a crystal reveal regions of crystal order/disorder and three−dimensional lattice tilts on the sub-100nm scale. The nanoscale lattice reorientation observed in the micron-sized peptide crystal lattices studied here provides a direct view of their plasticity. Knowledge of these features facilitates an improved understanding of peptide assemblies that could aid in the determination of structures from nano- and microcrystals by single or serial crystal electron diffraction.