bluuebunny/crossref_metadata_2025_split huggingface dataset:
Posterior predictive checking of multiple imputation models
Authors: Nguyen Cattram D. , Lee Katherine J. , Carlin John B. 
Published: May 2015

Multiple imputation is gaining popularity as a strategy for handling missing data, but there is a scarcity of tools for checking imputation models, a critical step in model fitting. Posterior predictive checking (PPC) has been recommended as an imputation diagnostic. PPC involves simulating “replicated” data from the posterior predictive distribution of the model under scrutiny. Model fit is assessed by examining whether the analysis from the observed data appears typical of results obtained from the replicates produced by the model. A proposed diagnostic measure is the posterior predictive “p‐value”, an extreme value of which (i.e., a value close to 0 or 1) suggests a misfit between the model and the data.The aim of this study was to evaluate the performance of the posterior predictive p‐value as an imputation diagnostic. Using simulation methods, we deliberately misspecified imputation models to determine whether posterior predictive p‐values were effective in identifying these problems. When estimating the regression parameter of interest, we found that more extreme p‐values were associated with poorer imputation model performance, although the results highlighted that traditional thresholds for classical p‐values do not apply in this context. A shortcoming of the PPC method was its reduced ability to detect misspecified models with increasing amounts of missing data. Despite the limitations of posterior predictive p‐values, they appear to have a valuable place in the imputer's toolkit. In addition to automated checking using p‐values, we recommend imputers perform graphical checks and examine other summaries of the test quantity distribution.
Site‐Specific Modification of the 6‐Amino Group of Adenosine in RNA by an Interstrand Functionality‐Transfer Reaction With an S‐Functionalized 4‐Thiothymidine
Authors: Oshiro Ikuya , Jitsuzaki Daichi , Onizuka Kazumitsu , Nishimoto Atsushi , Taniguchi Yosuke , Sasaki Shigeki 
Published: May 2015

AbstractNon‐natural RNA modifications have been widely used to study the function and structure of RNA. Expanding the study of RNA further requires versatile and efficient tools for site‐specific RNA modification. We recently established a new strategy for the site‐specific modification of RNA based on a functionality‐transfer reaction between an oligodeoxynucleotide (ODN) probe and an RNA substrate. 2′‐Deoxy‐6‐thioguanosine was used to anchor the transfer group, and the 4‐amino group of cytosine or the 2‐amino group of guanine was specifically modified. In this study, 2′‐deoxy‐4‐thiothymidine was adopted as a new platform to target the 6‐amino group of adenosine. The (E)‐pyridinyl vinyl keto transfer group was attached to the 4‐thioT in the ODN probe, and it was efficiently and specifically transferred to the 6‐amino group of the opposing adenosine in RNA in the presence of CuCl2. This method expands the available RNA target sites for specific modification.
The impact of ruxolitinib treatment on inflammation‐mediated comorbidities in myelofibrosis and related neoplasms
Authors: Bjørn Mads Emil , Hasselbalch Hans Carl 
Published: May 2015

Key clinical messageThe inflammation‐mediated comorbidities in myelofibrosis (MF) and related neoplasms (MPNs) likely reflect the concurrent immune deregulation and systemic inflammatory nature of the MPNs, emphasizing the link between chronic systemic inflammation, immune deregulation, and the malignant clone. JAK1‐2 inhibitors in MF‐patients reduce constitutional symptoms and splenomegaly, but also taget autoimmune and inflammation‐mediated comorbidities.
Rhodium Nanoparticles as Precursors for the Preparation of an Efficient and Recyclable Hydroformylation Catalyst
Authors: Garcia Marco A. S. , Oliveira Kelley C. B. , Costa Jean C. S. , Corio Paola , Gusevskaya Elena V. , dos Santos Eduardo N. , Rossi Liane M. 
Published: May 2015

AbstractDespite all the advances in the application of nanoparticle (NP) catalysts, they have received little attention in relation to the hydroformylation reaction. Herein, we present the preparation of a hydroformylation catalyst through the immobilization of air‐stable rhodium NPs onto a magnetic support functionalized with chelating phosphine ligands, which serves as an alternative to air‐sensitive precursors. The catalyst was active in hydroformylation and could be used in successive reactions with negligible metal leaching. The interaction between the rhodium NPs and the diphenylphosphine ligand was evidenced by an enhancement in the Raman spectrum of the ligand. Changes occurred in the Raman spectrum of the catalyst recovered after the reaction, which suggests that the rhodium NPs are precursors of active molecular species that are formed in situ. The supported catalyst was active for successive reactions even after it was exposed to air during the recycling runs and was easily recovered through magnetic separation.
Intramolecular Cooperative CC Bond Cleavage Reaction of 1,3‐Dicarbonyl Compounds with 2‐Iodoanilines to Give o‐(N‐Acylamino)aryl Ketones and Multisubstituted Indoles
Authors: Xing Qi , Lv Hui , Xia Chungu , Li Fuwei 
Published: May 2015

AbstractA copper‐catalyzed CC bond cleavage reaction of 1,3‐dicarbonyl compounds with 2‐iodoanilines was developed. In this process, the ortho effect played an important role in the reactivity and a new reaction pathway that involved a (2‐aminophenyl)‐bis‐(1,3‐dicarbonyl) copper species was clearly observed by a time‐course HRMS analysis of the reaction mixture. Unlike the previous reports, both the nucleophilic and electrophilic parts of the 1,3‐dicarbonyl compound were coupled with 2‐iodoaniline by CC bond cleavage to form o‐(N‐acylamino)aryl ketones, which could be efficiently converted into multisubstituted indoles.
Tautomerization‐Mediated Molecular Switching Between Six‐ and Seven‐Membered Rings Stabilized by Hydrogen Bonding
Authors: Storch Golo , Spallek Markus J. , Rominger Frank , Trapp Oliver 
Published: May 2015

Abstract1,3,4,6‐Tetraketones typically undergo keto–enol tautomerism forming bis‐enols stabilized by intramolecular hydrogen bonding in two six‐membered rings. However, 1,3,4,6‐tetraketones derived from the terpene ketone camphor and norcamphor exist as isomers with two distinguishable modes of intramolecular hydrogen bonding, namely, the formation of six‐ or seven‐membered rings. The structural requirements for this so far unknown behavior were investigated in detail by synthesis and comparison of structural analogues. Both isomers of such 1,3,4,6‐tetraketones were fully characterized in solution and in the solid state. Intriguingly, they slowly interconvert in solution by means of tautomerism–rotation cascades, as was corroborated by DFT calculations. The influence of temperature and complexation with the transition metals Pd, Rh, and Ir on the interconversion process was investigated.
The Guanidinium Unit in the Catalysis of Phosphoryl Transfer Reactions: From Molecular Spacers to Nanostructured Supports
Authors: Salvio Riccardo 
Published: May 2015

AbstractExamples of guanidinium‐based artificial phosphodiesterases are illustrated in this review article. A wide set of collected catalytic systems are presented, from the early examples to the most recent developments of the use of this unit in the design of supramolecular catalysts. Special attention is dedicated to illustrate the operating catalytic mechanism and the role of guanidine/ium units in the catalysis. One or more of these units can act by themselves or in conjunction with other active units. The analogy with the mechanism of enzymatic systems is presented and discussed. In the last part of this overview, recent examples of guanidinophosphodiesterases based on nanostructured supports are reported, namely gold‐monolayer‐protected clusters and polymer brushes grafted to silica nanoparticles. The issue of the dependence of the catalytic performance on the preorganization of the spacer is tackled and discussed in terms of effective molarity, a parameter that can be taken as a quantitative measurement of this preorganization for both conventional molecular linker and nanosized supports.
Absolute Asymmetric Synthesis of a Tetrahedral Silver Complex
Authors: Björemark Per Martin , Olsson Susanne , Kokoli Theonitsa , Håkansson Mikael 
Published: May 2015

AbstractEven though the isolation of tetrahedral stereoisomers usually presents a synthetic challenge, a highly enantioenriched tetrahedral silver complex could be easily accessed by either crystallization or Viedma ripening. The overall preparation may be regarded as an example of absolute asymmetric synthesis. Experimental results indicate that both crystallization and Viedma ripening follow a similar cluster‐controlled mechanism.
Hierarchical Interpolative Factorization for Elliptic Operators: Integral Equations
Authors: L. Ho Kenneth , Ying Lexing 
Published: May 2015

AbstractThis paper introduces the hierarchical interpolative factorization for integral equations (HIF‐IE) associated with elliptic problems in two and three dimensions. This factorization takes the form of an approximate generalized LU decomposition that permits the efficient application of the discretized operator and its inverse. HIF‐IE is based on the recursive skeletonization algorithm but incorporates a novel combination of two key features: (1) a matrix factorization framework for sparsifying structured dense matrices and (2) a recursive dimensional reduction strategy to decrease the cost. Thus, higher‐dimensional problems are effectively mapped to one dimension, and we conjecture that constructing, applying, and inverting the factorization all have linear or quasilinear complexity. Numerical experiments support this claim and further demonstrate the performance of our algorithm as a generalized fast multipole method, direct solver, and preconditioner. HIF‐IE is compatible with geometric adaptivity and can handle both boundary and volume problems.© 2016 Wiley Periodicals, Inc.
Unique morphologies of zinc oxide synthesized by thermal decomposition and co‐precipitation routes: Ultraviolet absorption and luminescence characteristics
Authors: Waqas Hassan , Salman Muhammad Saad , Riaz Asim , Riaz Naeem , Shabbir Saima 
Published: May 2015

Two facile and efficient methods, to synthesize zinc oxide (ZnO) particles with different morphologies, have been reported here. Thermal decomposition route yielded micron sized irregular shaped ZnO particles. While co‐precipitation method rendered transparent flakes which then transformed to hexagonal discs with relatively more uniform size and shape. These hexagonal discs were further converted to the cone type morphology when hexamethylenetetramine was added in the precursor solution. However, spherical type ZnO nanoparticles were obtained by incorporating polyvinyl alcohol during co‐precipitation strategy. XRD confirmed the formation of wurtzite structure in all the samples. FTIR spectroscopy revealed the presence of ZnO characteristic peaks. Moreover, 3‐D directional growths and the presence of UV‐Vis broadband multi‐absorption peaks, and green to orange photoluminescence emissions confirmed the potential application of the synthesized ZnO particles in various piezoelectric and luminescence applications.
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EXPO software for solving crystal structures by powder diffraction data: methods and application
Authors: Altomare Angela , Corriero Nicola , Cuocci Corrado , Falcicchio Aurelia , Moliterni Anna , Rizzi Rosanna 
Published: May 2015

Innovative methodologies, introduced in the software EXPO and working both in the reciprocal and in the direct space, can be successfully adopted for solving crystal structure by X‐ray powder diffraction data. The principles underlying these methodologies are summarized. Three representative examples of crystal structure solution of the peptides Z‐(Aib)2‐OH, Z‐(Aib)3‐O‐t‐Bu and Z‐(Aib)4‐OH are discussed in relation to their different degree of structure complexity.image
Highly efficient photocatalytic degradation of methyl orange and Rhodamine B by hierarchical BiOBr microspheres
Authors: Wang X. J. , Xu X. N. , Han Y. J. , Chen X. N. 
Published: May 2015

Hierarchical BiOBr microspheres were successfully synthesized via a solvothermal method by using the diethylene glycol(DEG) as the solvent and soft‐template. The as‐obtained products were characterized by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM), N2 adsorption–desorption and UV–Vis diffuse reflectance spectroscopy(DRS) techniques. The formation mechanism for the growth of hierarchical BiOBr microspheres has been studied. The possible mechanism of photocatalysis has been discussed. Remarkably, the as‐prepared BiOBr microspheres has a large specific surface area, which can reach a maximum surface area of 55.9307 m2/g. In addition, the superior enhanced photocatalytic activities of BiOBr microspheres were evaluated by the photodegradation of methyl orange (MO) and Rhodamine B (RhB) under visible‐light illumination, which presented the efficiency up to 98.10% just within 50 min and 98.64% within 30 min, respectively. BiOBr microspheres can be a promising candidate as highly efficient photocatalyst for decompositing of organic contaminants for environmental remediation.
On the Origin of the Improvement of Electrodeposited MnOx Films in Water Oxidation Catalysis Induced by Heat Treatment
Authors: Khan Munirah , Xiao Jie , Zhou Fengling , Yablonskikh Mikhail , MacFarlane Douglas R. , Spiccia Leone , Aziz Emad F. 
Published: May 2015

AbstractManganese oxides (MnOx) are considered to be promising catalysts for water oxidation. Building on our previous studies showing that the catalytic activity of MnOx films electrodeposited from aqueous electrolytes is improved by a simple heat treatment, we have explored the origin of the catalytic enhancement at an electronic level by X‐ray absorption spectroscopy (XAS). The Mn L‐edge XA spectra measured at various heating stages were fitted by linear combinations of the spectra of the well‐defined manganese oxides—MnO, Mn3O4, Mn2O3, MnO2 and birnessite. This analysis identified two major manganese oxides, Mn3O4 and birnessite, that constitute 97 % of the MnOx films. Moreover, the catalytic improvement on heat treatment at 90 °C is related to the conversion of a small amount of birnessite to the Mn3O4 phase, accompanied by an irreversible dehydration process. Further dehydration at higher temperature (120 °C), however, leads to a poorer catalytic performance.
Mediastinal granulomatous lymphadenitis in a population at risk for HIV and tuberculosis
Authors: De Wet Daniel R. , Wright Colleen A. , Schubert Pawel T. , Koegelenberg Coenraad F. N. , Louw Mercia , Diacon Andreas H. 
Published: May 2015

BackgroundGranulomatous inflammation on transbronchial needle aspirates from mediastinal lymph nodes is an infrequent yet important finding. We determined associations between cytomorphological features and underlying aetiology in an area of high prevalence of HIV‐infection and tuberculosis.MethodsWe identified cases with granulomatous inflammation on mediastinal aspirates from January 2003 to July 2010. Cytomorphological features were evaluated and graded according to a simple and reproducible system including the presence, quality (discrete or vague), and number (≤5 or more) of granulomas as well as the presence of necrosis, lymphocytes, multinucleated giant cells, and neutrophils.ResultsIn 81 patients (36 male, 9 HIV‐positive) the final diagnosis was tuberculosis in 37 (46%), sarcoidosis in 40 (49%), fibrosing mediastinitis in 1 (1%), and unknown in 3 (4%). The presence of necrosis (P < 0.001) and neutrophils (P = 0.05) was associated with tuberculosis and numerous discrete granulomas were associated with sarcoidosis (P = 0.03). All HIV‐positive patients were diagnosed with tuberculosis.ConclusionGranulomatous disease identified on TBNA from mediastinal lymph nodes is mostly associated with sarcoidosis and tuberculosis. Ancillary investigations for sarcoidosis are appropriate if numerous discrete granulomas are found. Tuberculosis must be excluded if necrosis and neutrophils are present and in HIV‐positive individuals, particularly in high‐burden areas of tuberculosis. Diagn. Cytopathol. 2015;43:696–700. © 2015 Wiley Periodicals, Inc.
Pleural‐based neuroblastoma‐like schwannoma: A case report with cytologic findings and review of literature
Authors: Adams Kristen , Liu Xuehui Susan , Akhtar Israh , Flowers Rhyne , Baliga Mithra 
Published: May 2015

We report a rare case of a 45‐year‐old African American woman with Neuroblastoma‐like Schwannoma (Neurilemmoma) occurring in the posterior mediastinum as a pleural‐based mass noted on computed tomography (CT) scan.A CT‐guided core biopsy of the mass was performed and core biopsy imprints were prepared during the procedure. A Diff‐Quik stain was performed for on‐site evaluation of specimen adequacy. The hematoxylin and eosin (H&E) staining was evaluated subsequently. Immunohistochemistry panels were applied to the same specimen.The cytologic findings of the core biopsy imprints showed hypercellular smears with a predominance of small cells with atypical features including hyperchromatic, round nuclei and occasional nucleoli. Neurocytic rosettes were particularly appreciated on H&E stain. The immunohistochemical results exhibited strong and diffuse immunoreactivity for S‐100 and vimentin.This case enriches the cytopathology literature by providing awareness of this tumor presenting as a posterior mediastinal mass. Diagn. Cytopathol. 2015;43:650–653. © 2015 Wiley Periodicals, Inc.
Transformation of graphene oxide by ferrous iron: Environmental implications
Authors: Wang Fanfan , Wang Fang , Gao Guandao , Chen Wei 
Published: May 2015

Abstract

Abiotic transformation of graphene oxide (GO) in aquatic environments can markedly affect the fate, transport, and effects of GO. The authors observed that ferrous iron (Fe[II])—an environmentally abundant, mild reductant—can significantly affect the physicochemical properties of GO (examined by treating aqueous GO suspensions with Fe2+ at room temperature, with doses of 0.032 mM Fe2+ per mg/L, 0.08 mM Fe2+ per mg/L, and 0.32 mM Fe2+ per mg/L GO). Microscopy data showed stacking of GO nanosheets on Fe2+ treatment. Spectroscopy evidence (X-ray diffraction, Fourier transform infrared transmission, Raman and X-ray photoelectron spectroscopy) showed significant changes in GO surface O-functionalities, in terms of loss of epoxy and carbonyl groups but increase of carboxyl group. The reduction mechanisms were verified by treating model organic molecules (styrene oxide, p-benzoquinone, and benzoic acid) resembling O-containing fragments of GO macromolecules with Fe2+. With sedimentation and adsorption experiments (using bisphenol A as a model contaminant), the authors demonstrated that Fe2+ reduced GOs still maintained relatively high colloidal stability, whereas their adsorption affinities were significantly enhanced. Thus, reduction of GO by mild reductants might be of greater environmental concerns than by stronger reducing agents (e.g., N2H4 and S2–), because the latter can result in too significant losses of surface O-functionalities and colloidal stability of GO. This interesting aspect should be given consideration in the risk assessment of GO. Environ Toxicol Chem 2015;34:1975–1982. © 2015 SETAC
The Pseudomonas Quinolone Signal (PQS)
Authors: Sams Thomas , Baker Ysobel , Hodgkinson James , Gross Jeremy , Spring David , Welch Martin 
Published: May 2015

AbstractPseudomonas aeruginosa is an opportunistic human pathogen that routinely appears near the top of public health threat lists worldwide. P. aeruginosa causes infections by secreting a wealth of exceptionally active exoproducts, leading to tissue damage. The synthesis of many of these virulence factors is now known to be under the control of the quorum sensing (QS) system. Over the last 15 years, the Pseudomonas quinolone signal (PQS) has been found to play a crucial role in QS by linking the two segments (las and rhl) of the P. aeruginosa N‐acylhomoserine lactone‐dependent QS signaling pathways. Herein, we present the discovery and elucidation of PQS signaling from a historical perspective, and also outline some of the outstanding research questions that still need to be addressed. Finally, we show how a better understanding of the biochemistry underpinning this pathway is leading to the development of new antimicrobial interventions with clear therapeutic potential.
Rainfall–Runoff Research on Upland Fields and A Comparison Of Kinematic Wave and Improved Tank Models
Authors: Chen Rong‐Song , Yang Kuo‐Hsien , Chang Shun‐Chun 
Published: May 2015

AbstractTaiwan is a small, populous island. Because little flat land remains available for building, a trend in hillside development has recently been observed. During the storm season, especially during typhoons, heavy rainfall is common; however, the volume of rainfall is difficult to predict. Heavy precipitation causes flash floods as surface and groundwater levels overwhelm drainage systems. Thus people living on, or close to, hills are at risk of experiencing flooding with little warning.We investigated two models to discuss their differences and impact of rainfall in upland locations. The tank model describes and simulates the hydrology of an area, and the kinematic wave model simulates rainfall at upland locations. We used two natural rainfall events that occurred in the Tai‐Chung basin as case studies for both models. We applied five statistical indexes, namely root mean squared error (RMSE), coefficient of efficiency (CE), percentage error of peak discharge (EQp), error in time to peak (ETp), and percentage error of total volume (EV) to evaluate and interpret hydraulic data and our simulation results. We determined both models to be applicable; the results showed the relative error in peak flow simulation for the upland tank model to be less than 10%. The total runoff forecasts for large‐scale typhoon rainfall exhibited large errors in both models. Less severe rainfall events produced lower percentage errors in both models.The simulated hydrograph was compared with the measured hydrograph, and little difference was observed in the performance of the models. However, the simulation results of the kinematic wave model were slightly more favourable, possibly because the more complex wave model included more parameters representing physiographic factors, such as the river flow parameters P and K, equivalent roughness values of N, the average slope values, and the infiltration values, thus increasing the accuracy of the simulation. The upland tank model did not require complex physiographic factor parameters; instead, the Multistar‐Powell method was used to model the upland tank model parameters to produce a simulated hydrograph, yielding results no less favourable than those produced using the kinematic wave model. In the absence of comprehensive measured data and physiographic factors, the upland tank model has practical uses. Copyright © 2015 John Wiley & Sons, Ltd.