bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel combination schemes of individual weighting factors sign subband adaptive filter algorithm
Authors: Yu Yi , Zhao Haiquan 
Published: January 2017

AbstractTo improve the performance of the recently presented individual weighting factors sign subband adaptive filter (IWF‐SSAF) algorithm, its 2 combination algorithms using different step sizes are proposed. The first algorithm is to convexly combine the weight vectors of a large step‐size IWF‐SSAF filter and a small step‐size one; and the second algorithm is to obtain a time‐varying step size for the IWF‐SSAF by combining a large step size and a small one. The minimization of the sum of the l1‐norm of subband errors is used to indirectly update the mixing parameters in these 2 algorithms through a modified sigmoidal function. Moreover, in the first algorithm, to implement a smooth transition from the large step‐size IWF‐SSAF filter to the small step‐size one, the component filters receive a cyclic feedback of the combined weight vector. Both proposed algorithms have almost the same convergence performance, but the second algorithm saves computational cost. Simulation results in impulsive noise scenarios demonstrate the superiority of our proposed algorithms.
Late‐Stage Diversification of Non‐Steroidal Anti‐Inflammatory Drugs by Transition Metal‐Catalyzed C–H Alkenylations, Thiolations and Selenylations
Authors: Ma Wenbo , Dong Hongbo , Wang Daoxin , Ackermann Lutz 
Published: January 2017

AbstractRuthenium‐ and silver‐catalyzed selective C–H alkenylations, thiolations and selenylations of phenazone (antipyrine) – a non‐steroidal anti‐inflammatory drug – have been developed. This method features ample substrate scope, affording typically the mono‐ortho alkenylated, thiolated and selenylated products in good yields with complete site selectivity control. This strategy offers an efficient protocol for the modification of antipyrine derivatives.magnified image
The α‐Thioglycoligase Derived from a GH89 α‐N‐Acetylglucosaminidase Synthesises α‐N‐Acetylglucosamine‐Based Glycosides of Biomedical Interest
Authors: Tshililo Ndivhuwo Olga , Strazzulli Andrea , Cobucci‐Ponzano Beatrice , Maurelli Luisa , Iacono Roberta , Bedini Emiliano , Corsaro Maria Michela , Strauss Erick , Moracci Marco 
Published: January 2017

AbstractWe report here on the preparation of a novel α‐thioglycoligase that can be used for the fast and efficient synthesis of α‐N‐acetylglucosamine‐based glycosides. Using the α‐N‐acetyl‐glucosaminidase from Clostridium perfringens of family GH89 (according to the Carbohydrate Active Enzymes classification) as starting point, we prepared mutants in the acid/base residue glutamic acid 483 that were found to have different synthetic efficiencies (maximal yields >80% after 24 h) in the presence of an activated donor and suitable acceptors. The synthetic potential of the Glu483 alanine mutant as an α‐thioglycoligase – only the third biocatalyst with this stereospecificity reported to date, and the first selective for the N‐acetylglucosamine moiety – was demonstrated by producing for the first time N‐acetyl‐α‐d‐glucosaminyl azide and N‐acetylglucosamine α‐thioglycosides in high yields. To showcase the application of such compounds, we show that they offer the wild‐type CpGH89 protection from thermal unfolding, demonstrating their potential as pharmacological chaperones for the treatment of mucopolysaccharidosis IIIB (Sanfilippo syndrome).magnified image
Ruthenium‐Catalyzed Aminomethylation and Methylation of Phenol Derivatives Utilizing Methanol as the C1 Source
Authors: Kim Seoksun , Hong Soon Hyeok 
Published: January 2017

AbstractA reaction involving ortho‐aminomethylation of phenol was developed via ruthenium‐catalyzed dehydrogenation of methanol, an environmentally benign C1 building block, without the use of reactive reagents. The reaction was successfully applied to a range of substrates. When naphthol was employed instead of phenol, only methylation was observed. On the basis of various mechanistic studies, we propose that formamide barely participates in the reaction, which mainly occurs through an iminium cation intermediate. The difference in the reactivities of phenol and naphthol is attributable to stronger basicity of naphtholate as a conjugate base owing to its lower aromaticity. Plausible reaction pathways were proposed for both reactions.magnified image
Sandwiched liquid metal membrane (SLiMM) for hydrogen purification
Authors: Yen Pei‐Shan , Deveau Nicholas D. , Datta Ravindra 
Published: January 2017

SignificancePalladium‐based membranes are currently the most advanced membranes for hydrogen separation and are on the verge of practical application. However, the search for alternative membranes continues in an effort to lower their cost and susceptibility to poisons. Here for the first time we report a novel sandwiched liquid metal membrane (SLiMM) for hydrogen separation. Permeation experiments indicate that the Ga/SiC SLiMM has a permeability ofat 500°C, which is 35 time higher than that for Pd under similar conditions. This promises a potential for application of SliMM in hydrogen purification. © 2016 American Institute of Chemical EngineersAIChE J, 63: 1483–1488, 2017
A Hexasaccharide Containing Rare 2‐O‐Sulfate‐Glucuronic Acid Residues Selectively Activates Heparin Cofactor II
Authors: Sankaranarayanan Nehru Viji , Strebel Tamara R. , Boothello Rio S. , Sheerin Kevin , Raghuraman Arjun , Sallas Florence , Mosier Philip D. , Watermeyer Nicholas D. , Oscarson Stefan , Desai Umesh R. 
Published: January 2017

AbstractGlycosaminoglycan (GAG) sequences that selectively target heparin cofactor II (HCII), a key serpin present in human plasma, remain unknown. Using a computational strategy on a library of 46 656 heparan sulfate hexasaccharides we identified a rare sequence consisting of consecutive glucuronic acid 2‐O‐sulfate residues as selectively targeting HCII. This and four other unique hexasaccharides were chemically synthesized. The designed sequence was found to activate HCII ca. 250‐fold, while leaving aside antithrombin, a closely related serpin, essentially unactivated. This group of rare designed hexasaccharides will help understand HCII function. More importantly, our results show for the first time that rigorous use of computational techniques can lead to discovery of unique GAG sequences that can selectively target GAG‐binding protein(s), which may lead to chemical biology or drug discovery tools.
Reductive Homocoupling of Organohalides Using Nickel(II) Chloride and Samarium Metal
Authors: Liu Yongjun , Xiao Shuhuan , Qi Yan , Du Feng 
Published: January 2017

AbstractA homocoupling method for organohalides and organosulfonates promoted by samarium metal and HMPA, and catalyzed by NiCl2 has been developed. Various organohalides (benzyl, aryl, heterocyclic, alkenyl and alkyl halides), α‐haloacetophenones, and phenyl organosulfonates were tolerated, and the reaction afforded coupling products with high efficiency. Excellent chemoselectivity was exhibited between halides and other groups, such as −COOH, −NO2, halogen, heterocyclic ring, ester, and ketone groups. The stereoselectivity suggested that the reaction mechanism might involve an organosamarium species.
DNA interaction with DAPI fluorescent dye: Force spectroscopy decouples two different binding modes
Authors: Reis L. A. , Rocha M. S. 
Published: January 2017

AbstractIn this work, we use force spectroscopy to investigate the interaction between the DAPI fluorescent dye and the λ‐DNA molecule under high (174 mM) and low (34 mM) ionic strengths. Firstly, we have measured the changes on the mechanical properties (persistence and contour lengths) of the DNA‐DAPI complexes as a function of the dye concentration in the sample. Then, we use recently developed models in order to connect the behavior of both mechanical properties to the physical chemistry of the interaction. Such analysis has allowed us to identify and to decouple two main binding modes, determining the relevant physicochemical (binding) parameters for each of these modes: minor groove binding, which saturates at very low DAPI concentrations (
0.50 μM) and presents equilibrium binding constants of the order of ∼107 M−1 for the two ionic strengths studied; and intercalation, which starts to play a significant role only after the saturation of the first mode, presenting much smaller equilibrium binding constants (∼105 M−1).
One‐Pot Synthesis of Polyhydroquinoline Derivatives through Organic‐Solid‐Acid‐Catalyzed Hantzsch Condensation Reaction
Authors: Mondal Sujan , Patra Bidhan Chandra , Bhaumik Asim 
Published: January 2017

AbstractWe report the synthesis of a new porous polymeric network (PPN) using triphenylamine and α,α‐dibromo‐p‐xylene by a Friedel–Crafts alkylation promoted by anhydrous FeCl3 as an oxidizing agent. Sulfonation of PPN led to a sulfonated porous polymeric network (SPPN) having high surface acidity and high BET surface area. We characterized the PPN and SPPN materials thoroughly by using powder XRD, FTIR spectroscopy, 13C solid‐state magic‐angle spinning NMR, field‐emission SEM, high‐resolution TEM, and N2 sorption techniques. The sulfonated material SPPN was then employed as a heterogeneous, reusable, and environmentally benign organic solid‐acid catalyst for the one‐pot synthesis of biologically important polyhydroquinoline derivatives under microwave irradiation.
Bistability in Organic Magnetic Materials: A Comparative Study of the Key Differences between Hysteretic and Non‐hysteretic Spin Transitions in Dithiazolyl Radicals
Authors: Vela Sergi , Reardon Michael B. , Jakobsche Charles E. , Turnbull Mark M. , Ribas‐Arino Jordi , Novoa Juan J. 
Published: January 2017

AbstractDithiazolyl (DTA)‐based radicals have furnished many examples of organic spin‐transition materials, some of them occurring with hysteresis and some others without. Herein, we present a combined computational and experimental study aimed at deciphering the factors controlling the existence or absence of hysteresis by comparing the phase transitions of 4‐cyanobenzo‐1,3,2‐dithiazolyl and 1,3,5‐trithia‐2,4,6‐triazapentalenyl radicals, which are prototypical examples of non‐bistable and bistable spin transitions, respectively. Both materials present low‐temperature diamagnetic and high‐temperature paramagnetic structures, characterized by dimerized (⋅⋅⋅A−A⋅⋅⋅A−A⋅⋅⋅)n and regular (⋅⋅⋅A⋅⋅⋅A⋅⋅⋅A⋅⋅⋅A⋅⋅⋅)n π‐stacks of radicals, respectively. We show that the regular π‐stacks are not potential energy minima but average structures arising from a dynamic inter‐conversion between two degenerate dimerized configurations: (⋅⋅⋅A−A⋅⋅⋅A−A⋅⋅⋅)n↔(‐A⋅⋅⋅A−A⋅⋅⋅A‐)n. The emergence of this intra‐stack dynamics upon heating gives rise to a second‐order phase transition that is responsible for the change in the dominant magnetic interactions of the system. This suggests that the promotion of a (⋅⋅⋅A−A⋅⋅⋅A−A⋅⋅⋅)n↔(‐A⋅⋅⋅A−A⋅⋅⋅A‐)n dynamics is a general mechanism for triggering spin transitions in DTA‐based materials. Yet, this intra‐stack dynamics does not suffice to generate bistability, which also requires a rearrangement of the intermolecular bonds between the π‐stacks via a first‐order phase transition.
Modellexperimente im Chemieunterricht.
Authors: Sommer Katrin , Toschka Christina , Schröder Laura , Schröder Thomas Philipp , Steff Henning , Fischer Roland A. 
Published: January 2017

AbstractWas sind Modellexperimente? Modellexperimente spielen im Chemieunterricht eine wichtige Rolle. Sie werden immer dann eingesetzt, wenn Experimente, die originale Sachverhalte widerspiegeln, aus Gründen der Komplexität, der Zugänglichkeit, des Gefahrenpotentials, der Handhabung und/oder der Kosten nicht zugänglich sind. In der chemiedidaktischen Literatur sowie in Chemie‐Schulbüchern besteht jedoch eine große Unschärfe bei dem Gebrauch dieses Begriffes. Für die Auseinandersetzung mit diesem Themenfeld ist es sowohl für die chemiedidaktische Forschung als auch für den Chemieunterricht wichtig, den Begriff Modellexperiment zu definieren, um u. a. bestehende Modellexperimente kritisch zu prüfen. Im vorliegenden Beitrag wird der Begriff Modellexperiment erstmalig für den Chemieunterricht Kriterien geleitet definiert. Diese Definition soll eine bewusste Abgrenzung der Modellexperimente von Simulationsmodellen, Denkmodellen und Funktionsmodellen etc. ermöglichen. Darauf aufbauend kann sich bei Experimenten, welche diese Kriterien eines Modellexperimentes aufweisen, die Quantität der modellierten Merkmale unterscheiden. Das wird im Modellierungsgrad ausgedrückt. Er erlaubt präzisere Aussagen über die Beziehung zwischen Modell und Original.
Large eddy simulations for blood dynamics in realistic stenotic carotids
Authors: Lancellotti Rocco Michele , Vergara Christian , Valdettaro Lorenzo , Bose Sanjeeb , Quarteroni Alfio 
Published: January 2017

AbstractIn this paper, we consider large eddy simulations (LES) for human stenotic carotids in presence of atheromasic plaque, a pathological condition where transitional effects to turbulence may occur, with relevant clinical implications such as plaque rupture. We provide a reference numerical solution obtained at high resolution without any subgrid scale model, to be used to assess the accuracy of LES simulations. In the context we are considering, ie, hemodynamics, we cannot refer to a statistically homogeneous, isotropic, and stationary turbulent regime; hence, the classical Kolmogorov theory cannot be used. For this reason, a mesh size and a time step are deemed fine enough if they allow to capture all the features of the velocity field in the shear layers developed after the bifurcation. To assess these requirements, we consider a simplified model of the evolution of a 2D shear layer, a relevant process in the formation of transitional effects in our case. Then, we compare the results of LES σ model (both static and dynamic) and mixed LES models (where also a similarity contribution is considered). In particular, we consider a realistic scenario of a human carotid, and we use the reference solution as gold standard. The results highlight the accuracy of the LES σ models, especially for the static model.
Nu@ge: A container‐based cloud computing service federation
Authors: Balouek‐Thomert Daniel , Caron Eddy , Gallard Pascal , Lefèvre Laurent 
Published: January 2017

SummaryThe adoption of cloud computing is still limited by several legal concerns that customers may have, such as data sovereignty. In cloud computing, data can be physically hosted in sensible locations, resulting in a lack of control for companies. In this context, we present the Nu@ge project, which aims at building a federation of container‐sized datacenters in the French territory. Nu@ge provides a software stack that enables companies to interconnect independent datacenters in a national mesh. A software architecture is presented and implemented as a federation of small datacenters deployed in France. The proposed architecture enables cooperation between local customized‐cloud managers and a federation‐wide middleware. It uses monitoring information from facilities and performance indicators from physical servers for managing the system, preventing incidents and considering energy efficiency. Additionally, a prototype of a container‐sized datacenter has been validated and patented.
Performance‐influence models of multigrid methods: A case study on triangular grids
Authors: Grebhahn Alexander , Rodrigo Carmen , Siegmund Norbert , Gaspar Francisco J. , Apel Sven 
Published: January 2017

SummaryMultigrid methods are among the most efficient algorithms for solving discretized partial differential equations. Typically, a multigrid system offers various configuration options to tune performance for different applications and hardware platforms. However, knowing the best performing configuration in advance is difficult, because measuring all multigrid system variants is costly. Instead of direct measurements, we use machine learning to predict the performance of the variants. Selecting a representative set of configurations for learning is nontrivial, although, but key to prediction accuracy. We investigate different sampling strategies to determine the tradeoff between accuracy and measurement effort. In a nutshell, we learn a performance‐influence model that captures the influences of configuration options and their interactions on the time to perform a multigrid iteration and relate this to existing domain knowledge. In an experiment on a multigrid system working on triangular grids, we found that combining pair‐wise sampling with the D‐Optimal experimental design for selecting a learning set yields the most accurate predictions. After measuring less than 1 % of all variants, we were able to predict the performance of all variants with an accuracy of 95.9 %. Furthermore, we were able to verify almost all knowledge on the performance behavior of multigrid methods provided by 2 experts.
Islands within an island: Population genetic structure of the endemic Sardinian newt,Euproctus platycephalus
Authors: Ball Sarah E. , Bovero Stefano , Sotgiu Giuseppe , Tessa Giulia , Angelini Claudio , Bielby Jon , Durrant Christopher , Favelli Marco , Gazzaniga Enrico , Garner Trenton W. J. 
Published: January 2017

AbstractThe identification of historic and contemporary barriers to dispersal is central to the conservation of endangered amphibians, but may be hindered by their complex life history and elusive nature. The complementary information generated by mitochondrial (mtDNA) and microsatellite markers generates a valuable tool in elucidating population structure and the impact of habitat fragmentation. We applied this approach to the study of an endangered montane newt,Euproctus platycephalus. Endemic to the Mediterranean island of Sardinia, it is threatened by anthropogenic activity, disease, and climate change. We have demonstrated a clear hierarchy of structure across genetically divergent and spatially distinct subpopulations. Divergence between three main mountain regions dominated genetic partitioning with both markers. Mitochondrial phylogeography revealed a deep division dating to ca. 1 million years ago (Mya), isolating the northern region, and further differentiation between the central and southern regions ca. 0.5 Mya, suggesting an association with Pleistocene severe glacial oscillations. Our findings are consistent with a model of southward range expansion during glacial periods, with postglacial range retraction to montane habitat and subsequent genetic isolation. Microsatellite markers revealed further strong population structure, demonstrating significant divergence within the central region, and partial differentiation within the south. The northern population showed reduced genetic diversity. Discordance between mitochondrial and microsatellite markers at this scale indicated a further complexity of population structure, in keeping with male‐biased dispersal and female philopatry. Our study underscores the need to elucidate cryptic population structure in the ecology and conservation strategies for endangered island‐restricted amphibians, especially in the context of disease and climate change.
The importance of time‐varying volatility and country interactions in forecasting economic activity
Authors: Trypsteen Steven 
Published: January 2017

AbstractThis paper examines the relative importance of allowing for time‐varying volatility and country interactions in a forecast model of economic activity. Allowing for these issues is done by augmenting autoregressive models of growth with cross‐country weighted averages of growth and the generalized autoregressive conditional heteroskedasticity framework. The forecasts are evaluated using statistical criteria through point and density forecasts, and an economic criterion based on forecasting recessions. The results show that, compared to an autoregressive model, both components improve forecast ability in terms of point and density forecasts, especially one‐period‐ahead forecasts, but that the forecast ability is not stable over time. The random walk model, however, still dominates in terms of forecasting recessions.
Evaluation of kodecytes using function‐spacer‐lipid constructs as a survey material for external proficiency testing for ABO subgrouping
Authors: Lim Young Ae , Kang Seon Joo 
Published: January 2017

BackgroundIt is not easy to find natural red blood cells (RBCs) with weak A (Aw) or weak B phenotype (Bw) for use as quality controls in ABO subgroup testing (subgrouping). The aim of this study was to prepare RBC kodecytes with synthetic blood group A and/or B function‐spacer‐lipid (FSL) constructs and to evaluate the possibility of using such kodecytes as a survey material for an external proficiency test (PT) to improve the quality of subgroup analysis.MethodsThree types of survey samples, including O phenotype RBCs and A kodecytes with Aw (0.02 mg/mL FSL‐A solution) and B kodecytes with Bw (0.15 mg/mL FSL‐B solution) were sent to 53 laboratories for an educational trial of PT for subgrouping. Cell typing was done using the manual tube technique.ResultsForty‐three laboratories responded, and the re‐activities of the survey samples varied from 0 to 4+ against anti‐A and anti‐B monoclonal reagents(MoAbs). Twenty‐nine laboratories (67%) correctly grouped the Bw kodecytes as Bw. Fifteen (35%), 21 (48%), and 6 (13%) laboratories grouped the Aw kodecytes as Aw, A2, and O phenotypes, respectively. The anti‐A MoAb clone affects the results of cell typing for Aw kodecytes. The stability of kodecytes was similar to that of natural O RBCs during storage.ConclusionOur kodecytes were useful as a survey material, and the survey results showed the necessity of materials for PT for subgrouping to improve the quality of laboratory analysis regardless of the different reactions according to the MoAb.
The total cholesterol to high‐density lipoprotein cholesterol as a predictor of poor outcomes in a Chinese population with acute ischaemic stroke
Authors: Chen Lifang , Xu Jianing , Sun Hao , Wu Hao , Zhang Jinsong 
Published: January 2017

BackgroundHigh admission cholesterol has been associated with better outcome after acute ischaemic stroke (AIS), but a paradox not completely illustrated. The purpose of this study was to investigate the effect of the total cholesterol to high‐density lipoprotein cholesterol (TC/HDL‐C) on short‐term survival after AIS.MethodsConsecutive patients admitted in 2013 and 2015 were enrolled in the present study. The logistic regression analysis was conducted to evaluate predictors of 3‐month outcomes. The primary endpoint was death. Secondary endpoint was good (modified Rankin Scale score 0‐2 or equal to prestrike modified Rankin Scale score) at 3 months.ResultsOf 871 patients enrolled in the final analysis, 94 (10.8%) individuals died during 3 months of observation. The serum TC and TC/HDL‐C levels at admission were significantly associated with stroke outcomes at 3 months, and the HDL‐C level was only correlated with the good outcomes at 3 months. Mortality risk was markedly decreased for patients with high TC/HDL‐C ratio (odds ratio: 0.23, 95% confidence interval [CI]: 0.10‐0.50 for Q4:Q1; P‐trend <.001) after adjustment. The effect of TC/HDL‐C ratio on the probability of good outcomes was still obvious (odds ratio: 2.18, 95% CI: 1.40‐3.39 for Q4:Q1; P‐trend=.029). According to the receiver operating characteristic analyses, the best discriminating factor was a TG/HDL‐C ≥3.37 (area under the ROC curve [AUC]=0.643, sensitivity 61.3%, specificity 61.7%) as well as the TC/HDL‐C ≥4.09 for good outcomes (AUC: 0.587, sensitivity 63.9%, specificity 79.7%).ConclusionsHigh TC/HDL‐C ratio may be associated with increased short‐term survival and better outcomes after AIS.