bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of Azido Polycarbonates via Bulk Polymerization of Halogenated Diols
Authors: St‐Charles Jean‐Christophe , Dubois Charles 
Published: February 2020

AbstractAzido polymers find use as energetic binders in a variety of composite explosive and propellant applications, but few azido polyesters have previously been reported: a method is introduced for the preparation of two azido polycarbonates, poly(2,2’‐bisazidomethyl‐1,3‐propyl carbonate) and poly(3‐azido‐1,2‐propyl carbonate), possible binder candidates for energetics applications. The preparation method for these polymers involves a two‐step synthesis starting from the bulk polymerization of the commercially sourced diols with diphenyl carbonate in the presence of lanthanum (III) acetylacetonate as a neutral catalyst, and subsequent azidation in cyclohexanone. The physical and thermal characteristics of each are reported, indicating properties similar to other azido‐polymers. The thermal and mechanical properties of cured azido polyester resin mixtures are the subject of ongoing research.
p‐Synephrine, ephedrine, p‐octopamine and m‐synephrine: Comparative mechanistic, physiological and pharmacological properties
Authors: Stohs Sidney J. , Shara Mohd , Ray Sidhartha D. 
Published: February 2020

AbstractConfusion and misunderstanding exist regarding the lack of cardiovascular and other adverse health effects of p‐synephrine and p‐octopamine relative to ephedrine and m‐synephrine (phenylephrine) which are known for their effects on the cardiovascular system. These four molecules have some structural similarities. However, the structural and stereochemical differences of p‐synephrine and p‐octopamine as related to ephedrine and m‐synephrine result in markedly different adrenergic receptor binding characteristics as well as other mechanistic differences which are reviewed. p‐Synephrine and p‐octopamine exhibit little binding to α‐1, α‐2, β‐1 and β‐2 adrenergic receptors, nor are they known to exhibit indirect actions leading to an increase in available levels of endogenous norepinephrine and epinephrine at commonly used doses. The relative absence of these mechanistic actions provides an explanation for their lack of production of cardiovascular effects at commonly used oral doses as compared to ephedrine and m‐synephrine. As a consequence, the effects of ephedrine and m‐synephrine cannot be directly extrapolated to p‐synephrine and p‐octopamine which exhibit significantly different pharmacokinetic, and physiological/pharmacological properties. These conclusions are supported by human, animal and in vitro studies that are discussed.
Assimilating polarimetric radar data with an ensemble Kalman filter: OSSEs with a tornadic supercell storm simulated with a two‐moment microphysics scheme
Authors: Zhu Kefeng , Xue Ming , Ouyang Kun , Jung Youngsun 
Published: February 2020

AbstractThe impact of assimilating differential reflectivity ZDR in addition to reflectivity (ZH) and radial velocity (Vr) from a polarimetric radar on the analysis of a tornadic supercell storm using an ensemble Kalman filter (EnKF) is studied in an observing system simulation experiment (OSSE) framework assuming a perfect forecast model. A double‐moment microphysics scheme is used to allow for proper simulation of polarimetric signatures. Root‐mean‐square errors of analysed state variables are calculated and the structure and intensity of analysed fields and derived quantities are examined. Compared to the baseline experiment assimilating radial velocity and reflectivity only, the assimilation of additional ZDR further reduces the errors of all state variables. The analysed hydrometeor fields are improved in both pattern and intensity distributions. Polarimetric signatures including ZDR and KDP columns, and ZDR arc in the supercell, are much better reproduced. Sensitivity experiments are performed that exclude the updating of hydrometeor number concentrations by ZDR or of state variables not directly linked to ZDR via observation operators. The results show that if number concentrations are not updated together with the mixing ratios, most of the benefit of assimilating ZDR is lost. Among other state variables, the updating of water vapour mixing ratio qv has the largest positive impact while the impact of updating vertical wind w comes in second. The updating of horizontal wind components or temperature has a much smaller but still noticeable impact. Reliable flow‐dependent cross‐covariances among the state variables and observation prior as derived from the forecast ensemble and used in EnKF are clearly very beneficial.
Advances in Rational Design and Materials of High‐Performance Stretchable Electromechanical Sensors
Authors: Dinh Toan , Nguyen Thanh , Phan Hoang‐Phuong , Nguyen Tuan‐Khoa , Dau Van Thanh , Nguyen Nam‐Trung , Dao Dzung Viet 
Published: February 2020

AbstractStretchable and wearable sensor technology has attracted significant interests and created high technological impact on portable healthcare and smart human–machine interfaces. Wearable electromechanical systems are an important part of this technology that has recently witnessed tremendous progress toward high‐performance devices for commercialization. Over the past few years, great attention has been paid to simultaneously enhance the sensitivity and stretchability of the electromechanical sensors toward high sensitivity, ultra‐stretchability, low power consumption or self‐power functionalities, miniaturisation as well as simplicity in design and fabrication. This work presents state‐of‐the‐art advanced materials and rational designs of electromechanical sensors for wearable applications. Advances in various sensing concepts and structural designs for intrinsic stretchable conductive materials as well as advanced rational platforms are discussed. In addition, the practical applications and challenges in the development of stretchable electromechanical sensors are briefly mentioned and highlighted.
Optimizing computational resource management for the scientific gateways ecosystems based on the service‐oriented paradigm
Authors: Martins de Oliveira Edvard , Estrella Júlio Cézar , Botazzo Delbem Alexandre Claudio , Souza Pardo Mário Henrique , Guzzo da Costa Fausto , Defelicibus Alexandre , Reiff‐Marganiec Stephan 
Published: February 2020

SummaryScience Gateways provide portals for experiments execution, regardless of the users' computational background. Nowadays its construction and performance need enhancement in terms of resource provision and task scheduling. We present the Modular Distributed Architecture to support the Protein Structure Prediction (MDAPSP), a Service‐Oriented Architecture for management and construction of Science Gateways, with resource provisioning on a heterogeneous environment. The Decision Maker, central module of MDAPSP, defines the best computational environment according to experiment parameters. The proof of concept for MDAPSP is presented in WorkflowSim, with two novel schedulers. Our results demonstrate good Quality of Service (QoS), capable of correctly distributing the workload, fair response times, providing load balance, and overall system improvement. The study case relies on PSP algorithms and the Galaxy framework, with monitoring experiments to show the bottlenecks and critical aspects.
Morphology and Physicochemical Properties of Starch from Waxy and Non‐Waxy Barley
Authors: Chen Xinyu , Shao Shanshan , Chen Mingxin , Hou Chunpu , Yu Xurun , Xiong Fei 
Published: February 2020

AbstractBarley flour is widely utilized in food and nonfood industries. Morphological, structural, and functional properties of starches extracted from waxy and non‐waxy barley are investigated and compared in this work. The morphology of starch granules in waxy and non‐waxy barley is similar while waxy barley has a higher proportion of A‐type starch granules and a lower proportion of B‐type starch granules than those of non‐waxy barley. Compared with non‐waxy barley starch, waxy barley starch shows higher amylopectin content with higher levels of amylopectin short and long branch‐chains; better ordered structures with higher relative crystallinity, IR ratio of 1045/1022 cm−1, and a double helical component, a lower amorphous and V‐type single helix components. The gelatinization temperature and enthalpy of waxy barley starch are higher than those of non‐waxy barley starch. Meanwhile, waxy barley starch presents higher swelling power, solubility, pasting viscosities, breakdown value, and lower setback value than those of non‐waxy barley starch. Furthermore, waxy barley starch is more susceptible to acid and enzymatic hydrolysis than non‐waxy barley starch. Results indicate that waxy and non‐waxy barley starches differ in physicochemical properties, and waxy barley may have a better mouthfeel and edible quality.
Nete Bridge in Lier – Long‐term experience with galvanized bridge components
Authors: Pinger Thomas 
Published: February 2020

AbstractIn Europe, hot‐dip galvanizing has hitherto had no appreciable application in bridge construction, which, despite decades of positive practical experience in building construction, is partly due to a lack of knowledge and regulations regarding the influence of galvanizing on the fatigue behaviour. By contrast, diverse examples from non‐European countries already confirm the technical and economic significance of galvanized bridge structures. Based on recent research and a guideline, the basics for wider application have been laid in the recent past. Nete Bridge in the Belgian city of Lier is one of the few road bridges with a fully galvanized steel support structure. The current state of the bridge, after more than 20 years in use, is described below – and a positive interim conclusion is drawn. Nete Bridge is in a good technical condition in terms of corrosion protection; no significant maintenance or repair measures have been required in this regard and are not expected in the future either. The example presented illustrates the feasibility of galvanizing bridge components as an alternative to the organic coating systems previously established. This also offers the bridge management authorities responsible economic benefits due to the very high durability and the associated very low maintenance costs.
Constructivism‐informed variation theory lesson designs in enriching and elevating science learning: Case studies of seamless learning design
Authors: Voon Xin P. , Wong Lung H. , Looi Chee K. , Chen Wenli 
Published: February 2020

AbstractThe constructivist paradigm opens abundant opportunities for effective knowledge construction in which student build knowledge and continually evaluated and improved their knowledge. The teaching mode under constructivist pedagogy redefines the role of students and the teachers and their interrelationships by creating a nurturing environment. By adapting constructivist framework, this article demonstrates how the variation of learning practices was critical in facilitating Primary 4 students in Singapore to carry out seamless science learning. The variation of learning practices enables the students to explore a particular scientific concept through various learning experience across the contexts. The study adapted the framework of the Objects of Constructivist Learning Model for the improvement of the seamless science learning design. When redesigning the lesson, a conscious effort was made by the teacher to create relevant patterns of variation, that is, varying certain critical aspect(s) while keeping other aspects of the object of learning invariant in order to help students discern those critical aspects. The findings contribute knowledge to how the Theory of Variation can be used in analyzing seamless learning as well as designing for constructivist learning experiences. The findings have also demonstrated that the complementary practice of constructivist pedagogy with variation theory as a viable and effective approach in seamless science learning, at which it deepened students' understanding through constructing the critical aspects of a phenomenon. Engagement with primary school students in experiencing the variations allowed the translation of theory into practice.
Investigation of chemical constituents and cytotoxic activity of the lichen Usnea undulata
Authors: Tram Nguyen Thi Thu , Anh Dinh Hoang , Thuc Huynh Hoang , Tuan Nguyen Trong 
Published: February 2020

AbstractLichens are a promising source of good anticancer agents. However the study on their bioactivities remains limited, especially in Vietnam. In this study, three extracts of lichen Usnea undulata Stirt. including n‐hexane, acetone and methanol were investigated for their cytotoxic activity on two human cancer cell lines (MCF‐7, NCI‐H460) and normal fibroblasts by sulforhodamine B (SRB) assay. The results showed that the n‐hexane extract exhibited the highest inhibition activity with IC50 5.26±0.13 μg/mL for MCF‐7 and 6.83±0.64 μg/mL for NCI‐H460, followed by acetone extract with IC50 66.44±1.37 μg/mL and 92.14±1.49 μg/mL, respectively. The methanol extract possessed weak cytotoxic effect against MCF‐7 and NCI‐H460 (IC50 values more than 100 μg/mL). The n‐hexane extract demonstrated interesting activity particularly on MCF‐7 as good selectivity index was recorded (SI > 3). The phytochemical study on n‐hexane and acetone extracts led to the isolation of four compounds including usnic acid (1), methyl orsellinate (2), methyl β‐orsellinate (3), 7‐hydroxyl‐5‐methoxy‐6‐methylphtalide (4) in which compound (4) was isolated the first time in such species. Their structures were elucidated by NMR analysis and compared with literature data.
Corrosion protection of carbon steel by polyurethane coatings containing graphene oxide
Authors: Duong Nguyen Thuy , An Tran Boi , Thao Phan Thanh , Oanh Vu Ke , Truc Trinh Anh , Vu Pham Gia , Hang To Thi Xuan 
Published: February 2020

AbstractIn this work, graphene oxide (GO) was prepared by modified Hummer's method. Polyurethane coatings with different GO concentrations (0.1‐0.5 %) were prepared for corrosion protection of carbon steel. Synthesized GO was characterized by FTIR and XRD. Corrosion resistance of polyurethane coatings containing GO was investigated by electrochemical impedance spectroscopy and salt fog test. The effects of GO on protection performance of polyurethane coatings depended on its dispersion ability. GO at a concentration of 0.1 % significantly improved corrosion resistance of polyurethane coatings.
Flavonoids from Camellia sinensis
Authors: Cuc Nguyen Thi , Nhiem Nguyen Xuan , Tai Bui Huu , Yen Pham Hai , Van Kiem Phan 
Published: February 2020

AbstractSix flavonoids camelliquercetiside C (1), epigallocatechin 3‐O‐gallate (2), rutin (3), quercetin‐3‐O‐β‐D‐glucopyranoside (4), epicatechin (5), and epigallocatechin (6) were isolated from the methanol extract of the leaves of Camellia sinensis by using combined chromatographic methods. Their structures were identified on the basis of spectroscopic evidence and by comparison with those reported in the literature.
Optimization of conditions for extraction of total polyphenols from dried tumeric (Curcuma longa L.) leaves using Response Surface Methodology
Authors: Thach Nguyen Ai 
Published: February 2020

AbstractTurmeric (Curcuma longa Linn) is a member of the Zingiberaceae family which is cultivated in tropical such as Vietnam and subtropical regions on over the world. Response surface method was used to optimize polyphenol compounds from dried tumeric leaves in different extraction conditions. Three main factors effect on total polyphenol content from dried tumeric leaves that include: extraction temperature (50, 60, and 70 oC), duration (40, 50, and 60 minutes), and solvent concentration (40, 50, and 60 %). The results of research showed that the optimal extraction condition of polyphenol from tumeric leaves was temperature at 68.3 oC for 59.9 minutes and 40 % ethanol that would give the highest polyphenols content 64.2 mg GAE/g DW. The results of this research indicated that the potential of using tumeric leaves as sources of natural antioxidant compounds.
The Pivotal Role of N‐O bonds in the Synthesis of Natural Products: A mini‐review
Authors: Kouklovsky Cyrille 
Published: February 2020

AbstractThis review focuses on the role of the nitrogen‐oxygen bond as a structural cornerstone for the construction of complex natural products. This bond may play several roles such as a functional protecting group or an activating group in carbonyl chemistry. Compounds containing a N‐O bond are generally prepared by cycloaddition of nitroso derivatives, nitrones or nitriles oxides. The first two reactions have been used in the synthesis of a N‐O bond containing natural product, pyrinodemin A, or for the synthesis of hydroxylated piperidine alkaloids after N‐O bond cleavage.
Higgs Quark Flavor Violation: Simplified Models and Status of General Two-Higgs-Doublet Model
Authors: Herrero-Garcia Juan , Nebot Miguel , Rajec Filip , White Martin , Williams Anthony G. 
Published: February 2020

Abstract
We study quark flavor violating interactions mediated by the Higgs boson h. We consider observables involving a third generation quark, of both the up and the down quark sectors, like h → bs and t → ch. Using an effective field theory approach we systematically list all the possible tree-level ultraviolet completions, which comprise models with vector-like quarks and/or extra scalars. We provide upper bounds on the flavor violating transitions allowed by current limits stemming from low energy processes, such as meson mixing and b → sγ. We find that scenarios with vector-like quarks always have very suppressed flavor-violating transitions, while a general Two-Higgs-Doublet Model may have a sizeable rate. To study the latter case in detail, we perform a full numerical simulation taking into account all relevant theoretical and phenomenological constraints. Our results show that BR(t → ch) [BR(h → bs)] are still allowed at the sub-percent [percent] level, which are being [may be] explored at the LHC [future colliders]. Finally, we have found that the mild mass-splitting discrepancy with respect to the SM in the Bs meson system can be accommodated in the Two-Higgs-Doublet Model. If confirmed, it yields the prediction BR(h → bs) ≃ 10−4, if the new contribution to the mass-splitting is dominated by tree-level Higgs boson exchange.
Magnetically charged AdS5 black holes from class $$ \mathcal{S} $$ theories on hyperbolic 3-manifolds
Authors: Bae Jin-Beom , Gang Dongmin , Lee Kimyeong 
Published: February 2020

Abstract
We study the twisted index of 4d $$ \mathcal{N} $$
N
= 2 class $$ \mathcal{S} $$
S
theories on a closed hyperbolic 3-manifold M3. Via 6d picture, the index can be written in terms of topological invariants called analytic torsions twisted by irreducible flat connections on the 3-manifold. Using the topological expression, we determine the full perturbative 1/N expansion of the twisted index. The leading part nicely matches the Bekestein-Hawking entropy of a magnetically charged black hole in the holographic dual AdS5 with AdS2 × M3 near-horizon.
Historical sunspot records
Authors: Arlt Rainer , Vaquero José M. 
Published: February 2020

AbstractSunspot observations are available in fairly good numbers since 1610, after the invention of the telescope. This review is concerned with those sunspot observations of which longer records and drawings in particular are available. Those records bear information beyond the classical sunspot numbers or group sunspot numbers. We begin with a brief summary on naked-eye sunspot observations, in particular those with drawings. They are followed by the records of drawings from 1610 to about 1900. The review is not a compilation of all known historical sunspot information. Some records contributing substantially to the sunspot number time series may therefore be absent. We also glance at the evolution of the understanding of what sunspots actually are, from 1610 to the 19th century. The final part of the review illuminates the physical quantities that can be derived from historical drawings.
Collecting egocentric network data with visual tools: A comparative study
Authors: Hollstein Betina , Töpfer Tom , Pfeffer Jürgen 
Published: February 2020

AbstractWhen collecting egocentric network data, visual representations of networks can function as a cognitive aid for depicting relationships, helping to maintain an overview of the relationships, and keeping the attention of the interviewees. Additionally, network maps can serve as a narration generator in qualitative and in mixed-methods studies. While varying visual instruments are used for collecting egocentric network data, little is known about differences among visual tools concerning the influence on the resulting network data, the usability for interviewees, and data validity. The article provides an overview of existing visually oriented tools that are used to collect egocentric networks and discusses their functions, advantages, and limitations. Then, we present results of an experimental study where we compare four different visual tools with regard to networks elicited, manageability, and the impact of follow-up questions. In order to assess the manageability of the four tools, we used the thinking aloud method. The results provide evidence that the decision in favor of a specific visual tool (structured vs. unstructured) can affect the size and composition of the elicited networks. Follow-up questions greatly affect the elicited networks and follow-up cues can level out differences among tools. Respondents tend to prefer the concentric circles tool, with some differences in preferences and manageability of tools between participants with low and those with high socioeconomic status. Finally, assets and drawbacks of the four instruments are discussed with regard to data quality and crucial aspects of the data collection process when using visual tools.
Slab break-off origin of 105 Ma A-type porphyritic granites in the Asa area of Tibet
Authors: Li Hang , Wang Ming , Zeng Xiao-Wen , Luo An-Bo , Yu Yun-Peng , Zeng Xian-Jin 
Published: February 2020

AbstractThe study of the petrogenesis of some magmatic rocks with special geochemical attributes provides effective information for us to explore the deep geodynamic background of their formation. A series of granitic porphyry dykes have been found in the mélange zone of the Asa region in southern Tibet, whose genesis may be closely related to the evolution of the Meso-Tethyan Ocean. Regional geodynamic evolution is investigated by whole-rock geochemical analysis, zircon U–Pb dating and Lu–Hf isotopic analysis of two porphyritic granites. The Asa porphyritic granites have high SiO2(74.29–78.65 wt %) and alkalis (Na2O + K2O = 6.51–9.35 wt %) contents, and low Al2O3(11.60–14.51 wt %), CaO (0.04–0.19 wt MgO (0.01–0.10 wt %) contents. They are enriched in Zr, Nb, Ce, Y and Hf and depleted in Ti, Ba, Sr and P, consistent with A-type granites. The samples are relatively rich in LREEs, with LREE/HREE ratios of 1.73–3.04. They display negative Eu anomalies (Eu/Eu* = 0.24–0.28) and obvious Ce anomalies in some samples. Zircon U–Pb analyses show that the porphyritic granites formed in late Early Cretaceous time, 107.4 to 105.5 Ma. Zircon εHf(t) values are in the range of 6.9 to 12.0. These data indicate that the porphyritic granites were sourced from interaction between mantle-derived and juvenile lower crust-derived melts, with the addition of oceanic sediment-derived melts. This occurred when the subducting Bangong–Nujiang oceanic crust split to create a slab window. Rising asthenosphere triggered re-melting of lower crust basalts, resulting in the formation of the late Early Cretaceous A-type granites around Asa.