bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fixed‐precision randomized low‐rank approximation methods for nonlinear model order reduction of large systems
Authors: Bach C. , Duddeck F. , Song L. 
Published: March 2019

SummaryMany model order reduction (MOR) methods employ a reduced basis
to approximate the state variables. For nonlinear models, V is often computed using the snapshot method. The associated low‐rank approximation of the snapshot matrix
can become very costly as m,n grow larger. Widely used conventional singular value decomposition methods have an asymptotic time complexity of
, which often makes them impractical for the reduction of large models with many snapshots. Different methods have been suggested to mitigate this problem, including iterative and incremental approaches. More recently, the use of fast and accurate randomized methods was proposed. However, most work so far has focused on fixed‐rank approximations, where rank k is assumed to be known a priori. In case of nonlinear MOR, stating a bound on the precision is usually more appropriate. We extend existing research on randomized fixed‐precision algorithms and propose a new heuristic for accelerating reduced basis computation by predicting the rank. Theoretical analysis and numerical results show a good performance of the new algorithms, which can be used for computing a reduced basis from large snapshot matrices, up to a given precision ε.
Implementation of an educational intervention to optimize self‐management and transition readiness in young adults with sickle cell disease
Authors: Calhoun Cecelia L. , Abel Regina A. , Pham Hai Ahn , Thompson Shomari , King Allison A. 
Published: March 2019

AbstractBackgroundThe transition from the pediatric setting to adult care is a well‐described period of morbidity and mortality for persons with sickle cell disease (SCD). We sought to measure the feasibility and effectiveness of providing skill‐based educational handouts on improving self‐management and transition readiness in adolescents with SCD.MethodsThis was a single‐center study in which participants completed a self‐assessment, the Adolescent Autonomy Checklist (AAC), to assess transition readiness and self‐management skills at baseline. After results were reviewed by the study coordinator, participants were provided with skill‐based handouts on noted areas of deficit. The AAC was subsequently completed at a follow‐up visit. All data were stored electronically and transferred into SAS for statistical analyses.ResultsSixty‐one patients completed the AAC at baseline and postintervention. At baseline, patients reported needing the most help with skills in money management, living arrangements, vocational skills, and emergency and healthcare skills. Postintervention, statistically significant improvements (P < 0.05) occurred in skills related to laundry, housekeeping, healthcare, and sexual development. A regression model exploring the time to follow‐up showed that most improvements could not be attributed to maturation alone.ConclusionThis study showed that educational handouts are a readily implementable and well‐accepted intervention among adolescents with SCD who identify challenges with skills necessary to successfully transition to adult care. Distinguishing which transition needs are best improved with this type of intervention will help to strengthen the multidisciplinary approach necessary to support adolescents and young adults with SCD as they matriculate to adult care.
Direct visualization of the nanoscopic three‐phase structure and stiffness of NBR/PVC blends by AFM nanomechanical mapping
Authors: Wang Wenpin , Yao Qing , Song Jianhui , Yao Binbin , Wang Hui , Li Zhibo 
Published: March 2019

ABSTRACTThe PeakForce Quantitative Nanomechanical Mapping based on atomic force microscope (AFM) is employed to first visualize and then quantify the elastic properties of a model nitrile rubber/poly(vinyl chloride) (NBR/PVC) blend at the nanoscale. This method allows us to consistently observe the changes in mechanical properties of each phase in polymer blends. Beyond measuring and discriminating elastic modulus and adhesion forces of each phase, we tune the AFM tips and the peak force parameters in order to reliably image samples. In view of viscoelastic difference in each phase, a three‐phase coexistence of an unmixed NBR phase, the mixed phase, and PVC microcrystallites is directly visualized in NBR/PVC blends. The nanomechanical investigation is also capable of recognizing the crosslinked rubber phase in cured rubber. The contribution of the mixed phase was quantified and it was found that the mechanical properties of blends are mainly determined by the homogeneity and stiffness of the mixed phase. This study furthers our understanding the structure–mechanical property relationship of thermoplastic elastomers, which is important for their potential design and applications. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 662–669
Reconstruction of a Photonic Qubit State with Reinforcement Learning
Authors: Yu Shang , Albarrán‐Arriagada Francisco , Retamal Juan Carlos , Wang Yi‐Tao , Liu Wei , Ke Zhi‐Jin , Meng Yu , Li Zhi‐Peng , Tang Jian‐Shun , Solano Enrique , Lamata Lucas , Li Chuan‐Feng , Guo Guang‐Can 
Published: March 2019

AbstractAn experiment is performed to reconstruct an unknown photonic quantum state with a limited amount of copies. A semiquantum reinforcement learning approach is employed to adapt one qubit state, an “agent,” to an unknown quantum state, an “environment,” by successive single‐shot measurements and feedback, in order to achieve maximum overlap. The experimental learning device herein, composed of a quantum photonics setup, can adjust the corresponding parameters to rotate the agent system based on the measurement outcomes “0” or “1” in the environment (i.e., reward/punishment signals). The results show that, when assisted by such a quantum machine learning technique, fidelities of the deterministic single‐photon agent states can achieve over 88% under a proper reward/punishment ratio within 50 iterations. This protocol offers a tool for reconstructing an unknown quantum state when only limited copies are provided, and can also be extended to higher dimensions, multipartite, and mixed quantum state scenarios.
Quantum Neural Network States: A Brief Review of Methods and Applications
Authors: Jia Zhih‐Ahn , Yi Biao , Zhai Rui , Wu Yu‐Chun , Guo Guang‐Can , Guo Guo‐Ping 
Published: March 2019

AbstractOne of the main challenges of quantum many‐body physics is the exponential growth in the dimensionality of the Hilbert space with system size. This growth makes solving the Schrödinger equation of the system extremely difficult. Nonetheless, many physical systems have a simplified internal structure that typically makes the parameters needed to characterize their ground states exponentially smaller. Many numerical methods then become available to capture the physics of the system. Among modern numerical techniques, neural networks, which show great power in approximating functions and extracting features of big data, are now attracting much interest. In this work, the progress in using artificial neural networks to build quantum many‐body states is reviewed. The Boltzmann machine representation is taken as a prototypical example to illustrate various aspects of the neural network states. The classical neural networks are also briefly reviewed, and it is illustrated how to use neural networks to represent quantum states and density operators. Some physical properties of the neural network states are discussed. For applications, the progress in many‐body calculations based on neural network states, the neural network state approach to tomography, and the classical simulation of quantum computing based on Boltzmann machine states are briefly reviewed.
Engineering for sustainable communities: Epistemic tools in support of equitable and consequential middle school engineering
Authors: Tan Edna , Calabrese Barton Angela , Benavides Aerin 
Published: March 2019

AbstractThis study is focused on engineering for sustainable communities (EfSC) in three middle school classrooms. Three in‐depth case studies are presented that explore how two related EfSC epistemic toolsets—(a) community engineering and ethnography tools for defining problems, and (b) integrating perspectives in design specification and optimization through iterative design sketch‐up and prototyping—work to support the following: (a) Students' recruitment of multiple epistemologies; (b) Navigation of multiple epistemologies; and (c) students' onto‐epistemological developments in engineering. Using a theoretical framework grounded in justice‐oriented notions of equity intersecting with multiple epistemologies, we investigated the impact of the related epistemic toolsets on students' engineering engagement. Specifically, the study focused on how the tools worked when they were taken up in particular ways by teacher and students, and how the nature of their iterative engagement with the tools led to outcomes in ways that were equitable and consequential, both to students' engineering experiences and their engineering onto‐epistemological developments, and also in responding to the community injustices prototypes were designed to address. Tensions that emerged are discussed with further reflection on what the EfSC epistemic toolsets suggest about the affordances of a productive epistemic space and the concomitant risks related to larger institutional norms, which constrain the extent of students' justice‐oriented engineering goals.
Synthesis, Structure Elucidation, Homology Modeling and Antifilarial Activity of 7‐Benzamidocoumarin Derivatives
Authors: Priyanka  , Neelabh  , Tiwari Neha , Sharma Rajesh K. , Gupta Poonam , Misra Sweta , Misra‐Bhattacharya Shailja , Butcher Ray J. , Singh Karuna , Katiyar Diksha 
Published: March 2019

AbstractA series of 7‐benzamidocoumarin derivatives 10–25 starting from 7‐amino coumarins 7 and 8 has been synthesized, characterized and evaluated in vitro for antifilarial activity against the human lymphatic filarial parasite, Brugia malayi. Compounds 13 and 20–23 showed permanent paralysis of the worm with 90–95% inhibition of motility of adult worms at 10 μM. All the synthesized compounds were docked on the modeled receptor of Onchocerca volvulus chitinase OvCHT1. Compound 13 with binding energy of −7.95 Kcal/mol showing three hydrogen bonds with the active site of the enzyme emerged as the best inhibitor.
Synthesis, Crystal Structures and Magnetic Properties of a Linear Trinuclear Cu(II) Complex [Cu3(ClCH2COO)6(bpy)2] and a Dinuclear Complex [Cu2(bpy)2(μ‐OH)(μ‐OH2) (μ‐ClCH2COO)](ClO4)2
Authors: Thatipamula Krishna Chary , Bhargavi Govindugari , Rajasekharan Melath V. 
Published: March 2019

AbstractTwo new triply bridged Cu(II) compounds [Cu3(bpy)2(μ‐ClCH2COO)6] (1) and [Cu2(bpy)2(μ‐OH)(μ‐OH2)(μ‐ClCH2COO)](ClO4)2 (2) (where, bpy=2,2’‐bipyridine) have been synthesized and their magnetic properties have been measured and correlated with structure. Compound 1 is a novel centrosymmetric tricopper compound with only carboxylate bridges. The terminal Cu2+ ions have [5 + 1] coordination while the central ion has [4 + 2] coordination. The three centres are antiferromagnetically coupled, the exchange parameters for the neighbouring and distant pairs of Cu(II) atoms being 2 J=–28.6 cm–1 and 2 J'=–1.0 cm–1, respectively. In compound 2 three types bridging modes are observed, viz., hydroxo, aquo and carboxylato. The two Cu(II) centers are ferromagnetically coupled (2 J=73.8 cm–1) as previously observed for several di‐copper complexes with the same bridges. DFT calculations are in reasonable agreement with the magnetic exchange parameters for both dinuclear and trinuclear compounds.
Memory of Periodic Thermal Stimulation in an Immune Complex
Authors: Stan Razvan C. , de Camargo Maristela M. 
Published: March 2019

AbstractProteins search their conformational space in order to attain the native fold and bind productively to relevant biological partners. Most proteins must be able to alternate between at least one active conformational state back to an inactive conformer, especially for macromolecules that perform work and need to optimize energy usage. This property may be invoked by a physical stimulus (eg. temperature) or by a chemical ligand, and may occur through mapping of the protein external environment onto a subset of protein conformers. We have stimulated with temperature cycles two partners of an immune complex before and after assembly. We have revealed with calorimetry that properties of the external stimulus are also found in the characteristics of the immune complex (i. e. periodic variations in the binding affinity). These results are important for delineating the bases of molecular memory ex vivo and may serve in the optimization of protein based sensors.
Synthesis of a New Series of Furopyranone‐ and Furocoumarin‐Chromone Conjugates Followed by In–Vitro Cytotoxicity Activity Evaluation, and Molecular Docking Study
Authors: Meydani Ali , Yousefi Samira , Gharibi Reza , Kazemi Shima , Teimouri Mohammad Bagher 
Published: March 2019

AbstractIn this work, new furopyranone‐ and furocoumarin‐chromone conjugates were successfully synthesized via the one‐pot three‐component condensation reactions of 3‐formylchromone derivatives, 4‐hydroxy‐6‐methylpyrone or 4‐hydroxycoumarin and alkyl or aryl isocyanides in refluxing toluene within 2 h. Molecular docking studies on cyclooxygenase enzymes (COX‐1, COX‐2) indicated that most derivatives have greater or moderate binding affinities than 3‐formylchromone which was used as a reference compound. Even some of the new products showed comparable binding energy towards the relative co‐crystalized ligand into COX‐1 and COX‐2. In general, all of the new products formed one to three hydrogen bonds with amino acid residues in the active site of both enzymes. Furthermore, the cytotoxicity activity of some selected compounds was investigated against human foreskin fibroblast cells (BJ) and human breast cancer cells (MDA‐MB‐231) using the MTT assay. All selected compounds exhibited significant cell growth inhibitory against cancerous cells with varied potencies when compared to 3‐formylchromone. However, they were much less toxic against normal cells.
Catalyst‐Free Synthesis of 2,3‐Benzodiazepines via Tetrahydrodiazirino[3,1‐a]isoquinoline Reacts with Sulfonyl Chlorides
Authors: Wang Kaikai , Li Yanli , Wang Xiaoyu , Zhu Baoku 
Published: March 2019

AbstractAn unexpected process from tetrahydrodiazirino[3,1‐a]isoquinolines and diversified sulfonyl chlorides RSO2Cl (R=aryl, alkyl) to deliver highly yields 4,5‐dihydro‐3H‐benzo[d][1,2]diazepine skeleton compounds was disclosed via N‐insertion ring‐opening reaction. The structural framework of 2,3‐benzodiazepines is unambiguously confirmed by single‐crystal X‐ray crystallographic analysis. The present protocol features mild reaction conditions, high yields and feasibility of large‐scale synthesis and catalyst‐free access to benzo[2,3]diazepines skeleton. In contrast, azomethine imines were produced by employing tetrahydrodiazirino[3,1‐a]isoquinoline reacts with aroyl chlorides under the same conditions.
Microwave Irradiation Tandem Hydroamination and Oxidative Cyclization of Natural Amino Acids with Diethyl Acetylenedicarboxylate for Functionalized Pyrrole Derivatives
Authors: Li Jisen , Duan Wenwen , Pan Xiaoxia , Ye Yanqing , Huang Chao 
Published: March 2019

AbstractUnder microwave irradiation from natural amino acids to nitrogen heterocyclic compounds, a tandem reaction of hydroamination and oxidative cyclization has been explored. Utilizing amino acids and diethyl acetylenedicarboxylate with high product yields on 83–95%, functionalized pyrrole derivatives can be prepared during 0.5‐0.75 h by copper oxide catalysis. With nonpolar side chains natural amino acids can be used to develop microwave‐assisted one‐pot transformations. Reaction conditions also adapt to other dialkyl acetylenedicarboxylates such as dimethyi acetylenedicarboxylate. Besides the reaction regulation was illustrated.
Multi‐Component Reaction of 6‐Aminouracils, Aldehydes and Secondary Amines: Conversion of the Products into Pyrimido[4,5‐d]pyrimidines through C‐H Amination/Cyclization
Authors: Borpatra Paran J. , Rastogi Gaurav K. , Saikia Ms. B‐S. , Deb Mohit L. , Baruah Pranjal K. 
Published: March 2019

AbstractReaction of 6‐aminouracils with aldehydes and secondary amines catalyzed by acetic acid is reported here. This is in fact a domino aza‐Michael reaction. 6‐Aminouracil reacts first with aldehyde and then amine attacks the newly formed C=C bond, which is established from the mass spectral analysis of the reaction mixture. The products of the reaction are cyclized to pyrimido[4,5‐d]‐pyrimidines via intramolecular α‐C−H functionalization of tertiary amine promoted by I2‐TBHP at room temperature in ethanol solvent. I2 (10 mol %) and TBHP (1.5 eq.) are used for the cyclization reactions. Based on few controlled experiments a tentative radical mechanism is proposed for the cyclization step.
Copper‐Catalysed C‐N Bond Formation Via Cross Dehydrogenative Coupling of 4H‐1,2,4‐Triazoles and Formamides
Authors: Inkollu Bhargavi , Karasala Bharat K. , Vidavalur Siddaiah 
Published: March 2019

AbstractThe first copper catalysed C−N formation between formamides and 3,5‐diphenyl‐4H‐1,2,4‐triazoles has been developed via cross dehydrogenative coupling reaction of C−H/N−H bonds. This protocol provides a simple and efficient approach to the synthesis of N,N‐dimethyl‐3,5‐diphenyl‐4H‐1,2,4‐triazole‐4‐carboxamides in moderate to good yields.
Halloysite ‐ Poly (ionic liquid) Nanocomposite as an Efficient Catalyst Support: Study of the Effects of Ionic Liquid Nature and Content on the Catalytic Activity
Authors: Sadjadi Samahe , Tavakolian Mina 
Published: March 2019

AbstractConsidering the high performance of ionic liquid decorated halloysite clay as a catalyst support, herein a halloysite ‐poly (ionic liquid) polymer composite is synthesized and characterized via BET, TGA, TEM, FTIR, XRD and ICP and then applied for the immobilization of Pd species to afford a catalyst for the hydrogenation of nitroarenes. To shed light to the effect of the content and nature of poly (ionic liquid) polymer on the catalytic activity, two control samples with different content and entity of poly (ionic liquid) polymer were synthesized and compared by FTIR, TGA and BET. The results confirmed that the content of poly (ionic liquid) polymer significantly affected the catalytic activity and the higher this value, the higher the Pd content and consequently the superior the catalytic activity would be. The study of the nature of poly (ionic liquid) polymer revealed that it did not dramatically influence the catalytic activity. However, the choice of the monomer affected the content of poly (ionic liquid) polymer formed on halloysite. Notably, the catalyst was highly selective toward reduction of nitro group and competing functionalities remained intact under the reaction condition. Moreover, the catalyst showed excellent recyclability with low Pd leaching.
RuCl3/ PPh3‐ Catalyzed Direct Conversion of Isoxazol‐5‐ones to 2,3‐Disubstituted Pyridines
Authors: Fernandes Alessandra A. G. , Stivanin Mateus L. , Jurberg Igor D. 
Published: March 2019

AbstractA novel catalytic system employing RuCl3/ PPh3is described for the preparation of 2,3‐disubstituted pyridines starting from 3,4‐disubstituted isoxazol‐5‐ones and acrolein. Mechanistic studies involving31P NMR, HRMS analyses and control experiments have been performed in order to support key events and intermediates proposed for this transformation.
A Remotely Controlled Transformable Soft Robot Based on Engineered Cardiac Tissue Construct
Authors: Xu Bingzhe , Han Xiaomin , Hu Yuwei , Luo Yiming , Chen Chia‐Hung , Chen Zi , Shi Peng 
Published: March 2019

AbstractMany living organisms undergo conspicuous or abrupt changes in body structure, which is often accompanied by a behavioral change. Inspired by the natural metamorphosis, robotic systems can be designed as reconfigurable to be multifunctional. Here, a tissue‐engineered transformable robot is developed, which can be remotely controlled to assume different mechanical structures for switching locomotive function. The soft robot is actuated by a muscular tail fin that emulates the swimming of whales and works as a cellular engine powered by the synchronized contraction of striated cardiac microtissue constructs. For a transition of locomotive behavior, the robot can be optically triggered to transform from a spread to a retracted form, which effectively changes the bending stiffness of the tail fins, thus minimizing the propulsion output from the “tail fin” and effectively switching off the engine. With the unprecedented controllability and responsiveness, the transformable robot is implemented to work as a cargo carrier for programmed delivery of chemotherapeutic agents to selectively eradicate cancer cells. It is believed that the realization of the transformable concept paves a pathway for potential development of intelligent biohybrid robotic systems.
Functionalized Carbon Dots on Graphene as Outstanding Non‐Metal Bifunctional Oxygen Electrocatalyst
Authors: Shin Juhun , Guo Jian , Zhao Tingting , Guo Zhengxiao 
Published: March 2019

AbstractCarbon‐based bifunctional electrocatalysts for both oxygen reduction and evolution reactions are potentially cost‐effective to replace noble metals in energy devices such as fuel cells, metal–air batteries, and photoelectrochemical converters, but enrichment of active sites holds the key to efficiency. Here, graphene frameworks with heteroatom‐doped carbon dots (CDs) are developed via a hydrothermal route followed by pyrolysis. The CDs are rationally prepared with careful selection of heteroatoms, embedded on the substrate to provide enriched active sites. Structural characterizations (e.g., transmission electron microscopy and X‐ray photoelectron spectroscopy) reveal the successful addition of CDs with nitrogen and sulfur species. Especially, a heat‐treated N,S codoped sample, NS‐CD@gf_a900, exhibits the optimum oxygen electrocatalysis, even closer to noble‐metal counterparts, as a result of the effect of active sites of the CDs and the synergistic behavior of N and S. Considering the importance of size and dopants of the material, this approach not only suggests a straightforward preparation route of nanocarbons, but also appoints the utilization of a new class of non‐metal species as efficient oxygen electrocatalysts.