bluuebunny/crossref_metadata_2025_split huggingface dataset:
BF3⋅OEt2‐Mediated Highly Stereoselective Synthesis of Trisubstituted‐Tetrahydrofuran via [3+2] Cycloaddition Reaction of 2‐Arylcyclopropyl Ketones with Aldehydes
Authors: Gupta Archana , Kholiya Rohit , Rawat Diwan S. 
Published: June 2017

AbstractA one‐step [3+2] cycloaddition of vicinal‐substituted donor–acceptor cyclopropanes to aldehydes catalyzed by BF3⋅OEt2 leading to 2,3,5‐trisubstituted tetrahydrofurans has been developed. This methodology has advantages of broad substrate scope, good yields and high diastereoselectivity.
Wet and Functional Adhesives from One‐Step Aqueous Self‐Assembly of Natural Amino Acids and Polyoxometalates
Authors: Xu Jing , Li Xiaodong , Li Jingfang , Li Xiangyi , Li Bao , Wang Yang , Wu Lixin , Li Wen 
Published: June 2017

AbstractSessile organisms have undergone long‐term evolution to develop the unique ability by positioning themselves on wet solid surface through secreting adhesive proteins. The present study reveals that natural amino acid monomers can also exhibit similar adhesion capacity. This kind of biomimetic adhesives were created by the one‐step aqueous assembly of basic amino acids with assistance of anionic polyoxometalates. The polyoxometalates not only serve as multivalent scaffold to initiate the supramolecular cross‐linking of amino acid molecules, but also function as a redox component, bestowing the wet adhesives with electrochromic features.
Unified Asymmetric Total Syntheses of (−)‐Alotaketals A–D and (−)‐Phorbaketal A
Authors: Cheng Hang , Zhang Zhihong , Yao Hongliang , Zhang Wei , Yu Jingxun , Tong Rongbiao 
Published: June 2017

AbstractThe novel tricyclic spiroketal alotane‐type sesterterpenoids showed strikingly different biological activities and potency with subtle structural alterations. Asymmetric total syntheses of the tricyclic sesterterpenoids (−)‐alotaketals A–D and (−)‐phorbaketal A were accomplished [29–31 steps from (−)‐malic acid] in a collective way for the first time. The key features of the strategy included 1) a new cascade cyclization of vinyl epoxy δ‐keto‐alcohols to forge the common tricyclic spiroketal intermediate, 2) a late‐stage allylic C−H oxidation, and 3) olefin cross‐metathesis to install the different side chains.
Novel cyclodextrin‐modified h‐BN@Pd(II) nanomaterial: An efficient and recoverable catalyst for ligand‐free C‐C cross‐coupling reactions in water
Authors: Ma Xiaojun , Lv Guanghui , Cheng Xu , Li Weijian , Sang Rui , Zhang Yong , Wang Qiantao , Hai Li , Wu Yong 
Published: June 2017

An environmentally friendly palladium(II) catalyst supported on cyclodextrin‐modified h‐BN was successfully prepared. The catalyst was characterized by FT‐IR, SEM, TG, XRD and XPS, and the loading level of Pd in h‐BN@β‐CD@Pd(II) was measured to be 0.088 mmol g−1 by ICP. It exhibits excellent catalytic activity for the Suzuki and Heck reactions in water, and can be easily separated and consecutively reused for at least nine times. In addition, a series of pharmacologically interesting products were successfully synthesized using this catalyst to demonstrate its potential applications in pharmaceutical industries. Above all, this work opens up an interesting and attractive avenue for the use of cyclodextrin‐functionalized h‐BN as an efficient support for hydrophilic heterogeneous catalysts.
Pine‐Leaf‐Shaped α‐Fe2O3 Micro/Nanostructures with a Preferred Orientation along the (110) Plane for Efficient Reversible Lithium Storage
Authors: Lin Qian , Chen Yubo , Zhong Yijun , Li Li , Zhou Wei , Shao Zongping 
Published: June 2017

AbstractPine‐leaf‐like α‐Fe2O3 micro/nanostructures with (110)‐facet orientations are prepared by a hydrothermal process using Mg2+ as an inducer and are investigated as conversion‐type anode materials for lithium‐ion batteries (LIBs). The unique micro/nanostructured building blocks significantly shorten the diffusion distance for lithium ions and improve the kinetics of the lithium ion extraction/insertion process, and the unique hierarchical morphology provide buffer space for the volume change of the electrode during the charge–discharge processes. Thus, favorable performances for lithium storage are demonstrated for the micro/nanostructured α‐Fe2O3 electrodes. In addition, the facet orientation of the particles is also found to have a substantial impact on the electrode performance, and the growth of the micro/nanoparticles in a preferred orientation along the (110) plane facilitated the anisotropic diffusion of lithium ions along channels in the [1
00] direction. From the dual benefits of the stable hierarchical micro/nanostructure and the preferred growth of the particles along the (110) plane, excellent electrochemical performance with a reversible capacity of up to 915 and 565 mA h g−1 at rates of 100 and 5000 mA g−1, respectively, and a capacity retention of 690 mA h g−1 at 1000 mA g−1 after 200 cycles is demonstrated for the α‐Fe2O3 micro/nanostructure prepared under optimized conditions.
Soluble Two‐Dimensional Covalent Organometallic Polymers by (Arene)Ruthenium‐Sulfur Chemistry
Authors: Coraux Johann , Hourani Wael , Müller Valentin L. , Lamare Simon , Kamaruddin Danial Aiman , Magaud Laurence , Bendiab Nedjma , Den Hertog Martien , Leynaud Olivier , Palmino Frank , Salut Roland , Chérioux Frédéric 
Published: June 2017

AbstractA class of two‐dimensional (2D) covalent organometallic polymers, with nanometer‐scale crosslinking, was obtained by arene(ruthenium) sulfur chemistry. Their ambivalent nature, with positively charged crosslinks and lypophylic branches is the key to the often sought‐for and usually hard‐to‐achieve solubility of 2D polymers in various kinds of solvents. Solubility is here controlled by the planarity of the polymer, which in turn controls Coulomb interactions between the polymer layers. High planarity is achieved for high symmetry crosslinks and short, rigid branches. Owing to their solubility, the polymers are easily processable, and can be handled as powder, deposited on surfaces by mere spin‐coating, or suspended across membranes by drop‐casting. The novel 2D materials are potential candidates as flexible membranes for catalysis, cancer therapy, and electronics.
Dithiafulvenyl‐Extended N‐Heterotriangulenes and Their Interaction with C60: Cooperative Fluorescence
Authors: Gliemann Bettina D. , Strauss Volker , Hitzenberger Jakob F. , Dral Pavlo O. , Hampel Frank , Gisselbrecht Jean‐Paul , Drewello Thomas , Thiel Walter , Guldi Dirk M. , Kivala Milan 
Published: June 2017

AbstractWe describe the synthesis as well as the electronic and photophysical characterization of novel N‐heterotriangulene derivatives decorated with methoxycarbonyl‐ and methyl‐sulfanyl‐substituted dithiafulvenyl moieties. The association of these electron‐rich compounds with fullerene C60 as electron acceptor was investigated by means of photophysical, voltammetric, and mass spectrometric methods and rationalized by DFT calculations. Importantly, light‐induced interactions between the dithiafulvene‐substituted N‐heterotriangulene bearing methoxycarbonyl substituents with C60 leads to cooperative fluorescence. Quantitative Job plot analyses by means of fluorescence spectroscopy and voltammetry confirm a 1:1 association with binding constants in the order of 104 m−1. Supportive results for the supramolecular assembly of both N‐heterotriangulenes with C60 were obtained by ESI mass spectrometric investigations in the gas phase.
Merging Photoredox with Brønsted Acid Catalysis: The Cross‐Dehydrogenative C−O Coupling for sp3 C−H Bond Peroxidation
Authors: Xia Qing , Wang Qiang , Yan Changcun , Dong Jianyang , Song Hongjian , Li Ling , Liu Yuxiu , Wang Qingmin , Liu Xiangming , Song Haibin 
Published: June 2017

AbstractA photoredox and Brønsted acid synergistically catalyzed cross‐dehydrogenative C−O coupling reaction is developed in which isochroman peroxyacetals are formed through sp3 C−H bond peroxidation. The reported method is characterized by its extremely mild reaction conditions, excellent yields, and broad substrate scope. An oxocarbenium ion p‐chlorobenzenesulfonate was speculated to be the reactive intermediate. The role of hemiacetals and oxygenated dimers on the effective stabilization of the oxocarbenium ion was investigated; the presence of acid appeared to establish equilibrium between hemiacetals and oxygenated dimers with the oxocarbenium ion pairs. The broad applicability of the method highlights the potential of the protocol for molecule synthesis.
A green trust‐distortion resistant trust management scheme on mobile ad hoc networks
Authors: Movahedi Zeinab , Hosseini Zahra 
Published: June 2017

SummaryTrust management is an emerging security approach used to conduct nodes' relationships in mobile ad hoc networks. It relates to assigning a trust level to each network component based on its cooperative behavior with respect to system goals. Because of its infrastructure‐less nature, frequent network dynamics, and severe resource constraints, it is complex to establish trust in such a network. Mainly, trust systems are vulnerable to attacks that make use of inherent properties of the trust model to alter the accuracy of estimated trust levels, referred to as trust‐distortion attacks. Because of the contradictory nature of such attacks, their detection can be confusing, complex, and energy‐demanding, especially in multiattack environments. To handle such threats, we propose a Green Trust‐distortion Resistant Trust Management Scheme, called GTRTMS, which handles different trust‐distortion attacks in multiattack environments. The proposed solution self‐adapts its trust knowledge monitoring according to the network context to conserve the energy of mobile nodes and reduce the produced CO2 emissions. Simulation results prove that GTRTMS exhibits significantly better performance than the other counterpart in presence of simultaneous and contradictory different trust‐distortion attacks.
Persistence of acetochlor, atrazine, and S-metolachlor in surface and subsurface horizons of 2 typic argiudolls under no-tillage
Authors: Bedmar Francisco , Gimenez Daniel , Costa José Luis , Daniel Peter E. 
Published: June 2017

Abstract

Variations in soil properties with depth strongly influence the degradation and persistence of herbicides, underlining the importance of studying these processes in soil horizons with distinctively different properties. The persistence of the herbicides acetochlor, atrazine, and S-metolachlor was measured in samples of the A, B, and C horizons of 2 Typic Argiudolls from Argentina under no-till management. The soils studied differed in soil organic carbon (OC) content, pH, particle size distribution, and structure. Quantification of herbicides in soil was done through high-performance liquid chromatography with diode array detector. There were interactions of herbicide × horizon (p &lt; 0.01) that resulted in degradation rates (k) of all herbicides decreasing, and their corresponding dissipation half-life (DT50) values increasing, with soil depth. Herbicide persistence across all soils and horizons ranged from 15 to 73 d for acetochlor, 13 to 29 d for atrazine, and 82 to 141 d for S-metolachlor, which had significantly (p &lt; 0.01) greater persistence than atrazine and acetochlor. The DT50 values of herbicides were negatively correlated with the contents of OC (correlation coefficients ranging from –0.496 to –0.773), phosphorus (–0.427 to –0.564), and nitrogen-nitrate (–0.507 to –0.662), and with microbial activity (–0.454 to –0.687) and the adsorption coefficient (–0.530 to –0.595); DT50s were positively correlated with pH (0.366 to 0.648). Adsorption was likely the most influential process in determining persistence of these herbicides in surface and subsurface horizons. The present study can potentially improve the prediction of the fate of acetochlor, atrazine, and S-metolachlor in soils because it includes much needed information on the degradation of the herbicides in subsurface horizons. Environ Toxicol Chem 2017;36:3065–3073. © 2017 SETAC
A systematic review of neuroimaging in delirium: predictors, correlates and consequences
Authors: Nitchingham Anita , Kumar Varun , Shenkin Susan , Ferguson Karen J. , Caplan Gideon A. 
Published: June 2017

ObjectiveNeuroimaging advances our understanding of delirium pathophysiology and its consequences. A previous systematic review identified 12 studies (total participants N = 764, delirium cases N = 194; years 1989–2007) and found associations with white matter hyperintensities (WMH) and cerebral atrophy. Our objectives were to perform an updated systematic review of neuroimaging studies in delirium published since January 2006 and summarise the available literature on predictors, correlates or outcomes.MethodsStudies were identified by keyword and MeSH‐based electronic searches of EMBASE, MEDLINE and PsycINFO combining terms for neuroimaging, brain structure and delirium. We included neuroimaging studies of delirium in adults using validated delirium assessment methods.ResultsThirty‐two studies (total N = 3187, delirium N = 1086) met the inclusion criteria. Imaging included magnetic resonance imaging (MRI; N = 9), computed tomography (N = 4), diffusion tensor imaging (N = 3), transcranial Doppler (N = 5), near infrared spectroscopy (N = 5), functional‐MRI (N = 2), single photon emission computed tomography (N = 1), proton MRI spectroscopy (N = 1), arterial spin‐labelling MRI (N = 1) and 2‐13fluoro‐2‐deoxyglucose positron emission tomography (N = 1). Despite heterogeneity in study design, delirium was associated with WMH, lower brain volume, atrophy, dysconnectivity, impaired cerebral autoregulation, reduced blood flow and cerebral oxygenation and glucose hypometabolism. There was evidence of long‐term brain changes following intensive care unit delirium.ConclusionsNeuroimaging is now used more widely in delirium research due to advances in technology. However, imaging delirious patients presents challenges leading to methodological limitations and restricted generalisability. The findings that atrophy and WMH burden predict delirium replicates findings from the original review, while advanced techniques have identified other substrates and mechanisms that warrant further investigation.
Blurring the Boundaries Between School and Community: Implementing Connected Learning Principles in English Classrooms
Authors: Cartun Ashley , Penuel William R. , West‐Puckett Stephanie 
Published: June 2017

AbstractIn participatory cultures, the lines between producers and consumers of text are blurred, and communities emerge that are based on shared interest and peer support. Although literacy scholarship has mostly focused on youth engagement and literacy practices within online participatory cultures, scholars in the learning sciences investigate these ideas through connected learning. This article explores bringing connected learning principles into English classrooms and examines how one high school, partnering with the National Writing Project, redesigned their senior English course and senior capstone project around connected learning. The authors highlight its design and share students’ experiences with the project to illustrate the possibilities and tensions around designing for such a project in school settings.
Economic Relevance and Planning for Literacy Instruction: Reconciling Competing Ideologies
Authors: Boggs George L. , Stewart Trevor Thomas , Jansky Timothy A. 
Published: June 2017

AbstractThe language of economics and economic imperatives are driving standardized school reform in the United States without input from teachers. This teacher action research project responds to concerns about contemporary school reforms by considering how economics‐minded dialogue about literacy education can help teachers support students’ literacy practices. The study explores the use of an economic model for planning, implementing, and evaluating composition instruction based in sociocultural literacy research. The model classifies classroom activities according to economic principles of connectedness and production. This model supported collaborative dialogue about writing instruction problems. Three phases—cycles of planning, implementation, and evaluation of instruction—progressively demonstrated how thinking economically about literacy instruction supported a teacher's decision making toward student‐centered writing instruction. The study frames economic analysis as a positive support for students’ acquisition of new literacies. It also suggests how teachers may make sense of economics‐oriented educational reform goals for literacy instruction.
Human embryonic stem cell dispersion in electrospun PCL fiber scaffolds by coating with laminin‐521 and E‐cadherin‐Fc
Authors: Leino Mattias , Astrand Carolina , Hughes‐Brittain Nanayaa , Robb Brendan , McKean Robert , Chotteau Véronique 
Published: June 2017

AbstractAdvances in human pluripotent cell cultivation and differentiation protocols have led to production of stem cell‐derived progenitors as a promising cell source for replacement therapy. Three‐dimensional (3‐D) culture is a better mimic of the natural niche for stem cells and is widely used for disease modeling. Here, we describe a nonaggregate culture system of human embryonic stem cells inside electrospun polycaprolactone (PCL) fiber scaffolds combined with defined extracellular proteins naturally occurring in the stem cell niche. PCL fiber scaffolds coated with recombinant human laminin‐521 readily supported initial stem cell attachment and growth from a single‐cell suspension. The combination of recombinant E‐cadherin‐Fc and laminin‐521 further improved cell dispersion rendering a uniform cell population. Finally, we showed that the cells cultured in E‐cadherin‐Fc‐ and laminin‐521‐coated PCL scaffolds could differentiate into all three germ layers. Importantly, we provided a chemically defined 3‐D system in which pluripotent stem cells grown and differentiated avoiding the formation of cell aggregates. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1226–1236, 2018.
MRI‐based assessment of acute effect of head‐down tilt position on intracranial hemodynamics and hydrodynamics
Authors: Ishida Shota , Miyati Tosiaki , Ohno Naoki , Hiratsuka Shinnosuke , Alperin Noam , Mase Mitsuhito , Gabata Toshifumi 
Published: June 2017

PurposeTo quantify the acute effect of the head‐down tilt (HDT) posture on intracranial hemodynamics and hydrodynamics.Materials and MethodsWe evaluated the intracranial physiological parameters, blood flow‐related parameters, and brain morphology in the HDT (–6° and –12°) and the horizontal supine (HS) positions. Seven and 15 healthy subjects were scanned for each position using 3.0 T magnetic resonance imaging system. The peak‐to‐peak intracranial volume change, the peak‐to‐peak cerebrospinal fluid (CSF) pressure gradient (PGp‐p), and the intracranial compliance index were calculated from the blood and CSF flow determined using a cine phase‐contrast technique. The brain volumetry was conducted using SPM12. The measurements were compared using the Wilcoxon signed‐rank test or a paired t‐test.ResultsNo measurements changed in the –6° HDT. The PGp‐p and venous outflow of the internal jugular veins (IJVs) in the –12° HDT were significantly increased compared to the HS (P < 0.001 and P = 0.025, respectively). The cross‐sectional areas of the IJVs were significantly larger (P < 0.001), and the maximum, minimum, and mean blood flow velocity of the IJVs were significantly decreased (P = 0.003, < 0.001, and = 0.001, respectively) in the –12° HDT. The mean blood flow velocities of the internal carotid arteries were decreased (P = 0.023). Neither position affected the brain volume.ConclusionPressure gradient and venous outflow were increased in accordance with the elevation of the intracranial pressure as an acute effect of the HDT. However, the CSF was not constantly shifted from the spinal canal to the cranium.Level of Evidence: 2Technical Efficacy: Stage 1J. Magn. Reson. Imaging 2018;47:565–571.
Application of higher energy collisional dissociation (HCD) to the fragmentation of new DOTA‐based labels and N‐termini DOTA‐labeled peptides
Authors: El‐Khatib A. H. , He Y. , Esteban‐Fernández D. , Linscheid M. W. 
Published: June 2017

1,4,7,10‐Tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) derivatives are applied in quantitative proteomics owing to their ability to react with different functional groups, to harbor lanthanoides and hence their compatibility with molecular and elemental mass spectrometry. The new DOTA derivatives, namely Ln‐MeCAT‐Click and Ln‐DOTA‐Dimedone, allow efficient thiol labeling and targeting sulfenation as an important post‐translational modification, respectively. Quantitative applications require the investigation of fragmentation behavior of these reagents. Therefore, the fragmentation behavior of Ln‐MeCAT‐Click and Ln‐DOTA‐Dimedone was studied using collision‐induced dissociation (CID), infrared multiphoton dissociation (IRMPD) and higher‐energy collision dissociation (HCD) using different energy levels, and the efficiency of reporter ion production was estimated. The efficiency of characteristic fragment formation was in the order IRMPD > HCD (normal energy level) > CID.On the other hand, the application of HCD at high energy levels (HCD@HE; NCE > 250%) resulted in a significant increase in reporter ion production (33–54%). This new strategy was successfully applied to generate label‐specific reporter ions for DOTA amino labeling at the N‐termini and in a quantitative fashion for the estimation of amino:thiol ratio in peptides. Copyright © 2017 John Wiley & Sons, Ltd.
Validation of reference genes for quantitative gene expression analysis in experimental epilepsy
Authors: Sadangi Chinmaya , Rosenow Felix , Norwood Braxton A. 
Published: June 2017

AbstractTo grasp the molecular mechanisms and pathophysiology underlying epilepsy development (epileptogenesis) and epilepsy itself, it is important to understand the gene expression changes that occur during these phases. Quantitative real‐time polymerase chain reaction (qPCR) is a technique that rapidly and accurately determines gene expression changes. It is crucial, however, that stable reference genes are selected for each experimental condition to ensure that accurate values are obtained for genes of interest. If reference genes are unstably expressed, this can lead to inaccurate data and erroneous conclusions. To date, epilepsy studies have used mostly single, nonvalidated reference genes. This is the first study to systematically evaluate reference genes in male Sprague–Dawley rat models of epilepsy. We assessed 15 potential reference genes in hippocampal tissue obtained from 2 different models during epileptogenesis, 1 model during chronic epilepsy, and a model of noninjurious seizures. Reference gene ranking varied between models and also differed between epileptogenesis and chronic epilepsy time points. There was also some variance between the four mathematical models used to rank reference genes. Notably, we found novel reference genes to be more stably expressed than those most often used in experimental epilepsy studies. The consequence of these findings is that reference genes suitable for one epilepsy model may not be appropriate for others and that reference genes can change over time. It is, therefore, critically important to validate potential reference genes before using them as normalizing factors in expression analysis in order to ensure accurate, valid results.