bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Enantioselective Desymmetrizing Fischer Indolization through Dynamic Kinetic Resolution
Authors: Ghosh Biki , Balhara Reena , Jindal Garima , Mukherjee Santanu 
Published: February 2021

AbstractThe first catalytic enantioselective Fischer indolization of prochiral diketones containing enantiotopic carbonyl groups is developed and shown to proceed through dynamic kinetic resolution (DKR). Catalyzed by the combination of a spirocyclic chiral phosphoric acid and ZnCl2 (Lewis acid assisted Brønsted acid), this direct approach combines 2,2‐disubstituted cyclopentane‐1,3‐diones with N‐protected phenylhydrazines to furnish cyclopenta[b]indole derivatives containing an all‐carbon quaternary stereocenter with good to excellent enantioselectivities.
Enantioselective Synthesis of Pyroglutamic Acid Esters from Glycinate via Carbonyl Catalysis
Authors: Ma Jiguo , Zhou Qinghai , Song Guanshui , Song Yongchang , Zhao Guoqing , Ding Kuiling , Zhao Baoguo 
Published: February 2021

AbstractDirect α‐functionalization of NH2‐free glycinates with relatively weak electrophiles such as α,β‐unsaturated esters still remains a big challenge in organic synthesis. With chiral pyridoxal 5 d as a carbonyl catalyst, direct asymmetric conjugated addition at the α‐C of glycinate 1 a with α,β‐unsaturated esters 2 has been successfully realized, to produce various chiral pyroglutamic acid esters 4 in 14–96 % yields with 81–97 % ee's after in situ lactamization. The trans and cis diastereomers can be obtained at the same time by chromatography and both of them can be easily converted into chiral 4‐substituted pyrrolidin‐2‐ones such as Alzheimer's drug Rolipram (11) with the same absolute configuration via tert‐butyl group removal and subsequent Barton decarboxylation.
Stabilization of Polynitrogen Anions in Tantalum–Nitrogen Compounds at High Pressure
Authors: Bykov Maxim , Bykova Elena , Ponomareva Alena V. , Abrikosov Igor A. , Chariton Stella , Prakapenka Vitali B. , Mahmood Mohammad F. , Dubrovinsky Leonid , Goncharov Alexander F. 
Published: February 2021

AbstractThe synthesis of polynitrogen compounds is of great importance due to their potential as high‐energy‐density materials (HEDM), but because of the intrinsic instability of these compounds, their synthesis and stabilization is a fundamental challenge. Polymeric nitrogen units which may be stabilized in compounds with metals at high pressure are now restricted to non‐branched chains with an average N−N bond order of 1.25, limiting their HEDM performances. Herein, we demonstrate the synthesis of a novel polynitrogen compound TaN5 via a direct reaction between tantalum and nitrogen in a diamond anvil cell at circa 100 GPa. TaN5 is the first example of a material containing branched all‐single‐bonded nitrogen chains [N55−]∞. Apart from that we discover two novel Ta–N compounds: TaN4 with finite N44− chains and the incommensurately modulated compound TaN2−x, which is recoverable at ambient conditions.
π‐Interpenetrated 3D Covalent Organic Frameworks from Distorted Polycyclic Aromatic Hydrocarbons
Authors: Martínez‐Abadía Marta , Strutyński Karol , Lerma‐Berlanga Belén , Stoppiello Craig T. , Khlobystov Andrei N. , Martí‐Gastaldo Carlos , Saeki Akinori , Melle‐Franco Manuel , Mateo‐Alonso Aurelio 
Published: February 2021

AbstractThree‐dimensional covalent organic frameworks (3D COFs) with a pcu topology have been obtained from distorted polycyclic aromatic hydrocarbons acting as triangular antiprismatic (D3d) nodes. Such 3D COFs are six‐fold interpenetrated as the result of interframework π‐stacking, which enable charge transport properties that are not expected for 3D COFs.
A Solid‐State Intramolecular Wittig Reaction Enables Efficient Synthesis of Endofullerenes Including Ne@C60, 3He@C60, and HD@C60
Authors: Hoffman Gabriela , Walkey Mark C. , Gräsvik John , Bacanu George R. , Alom Shamim , Bloodworth Sally , Light Mark E. , Levitt Malcolm H. , Whitby Richard J. 
Published: February 2021

AbstractAn open‐cage fullerene incorporating phosphorous ylid and carbonyl group moieties on the rim of the orifice can be filled with gases (H2, He, Ne) in the solid state, and the cage opening then contracted in situ by raising the temperature to complete an intramolecular Wittig reaction, trapping the atom or molecule inside. Known transformations complete conversion of the product fullerene to C60 containing the endohedral species. As well as providing an improved synthesis of large quantities of 4He@C60, H2@C60, and D2@C60, the method allows the efficient incorporation of expensive gases such as HD and 3He, to prepare HD@C60 and 3He@C60. The method also enables the first synthesis of Ne@C60 by molecular surgery, and its characterization by crystallography and 13C NMR spectroscopy.
Chiral Mesostructured NiO Films with Spin Polarisation
Authors: Bai Te , Ai Jing , Liao Liyang , Luo Junwei , Song Cheng , Duan Yingying , Han Lu , Che Shunai 
Published: February 2021

AbstractSpin polarisation is found in the centrosymmetric nonferromagnetic crystals, chiral mesostructured NiO films (CMNFs), fabricated through the symmetry‐breaking effect of a chiral molecule. Two levels of chirality were identified: primary nanoflakes with atomically twisted crystal lattices and secondary helical stacking of the nanoflakes. Spin polarisation of the CMNFs was confirmed by chirality‐dependent magnetic‐tip conducting atomic force microscopy (mc‐AFM) and magnetic field‐independent magnetic circular dichroism (MCD). Electron transfer in the symmetry‐breaking electric field was speculated to create chirality‐dependent effective magnetic fields. The asymmetric spin–orbit coupling (SOC) generated by effective magnetic fields selectively modifies the opposite spin motion in the antipodal CMNFs. Our findings provide fundamental insights for directional spin control in unprecedented functional inorganic materials.
Electrochemical Characterization of Single Layer Graphene/Electrolyte Interface: Effect of Solvent on the Interfacial Capacitance
Authors: Wu Yih‐Chyng , Ye Jianglin , Jiang Gengping , Ni Kun , Shu Na , Taberna Pierre‐Louis , Zhu Yanwu , Simon Patrice 
Published: February 2021

AbstractThe development of the basic understanding of the charge storage mechanisms in electrodes for energy storage applications needs deep characterization of the electrode/electrolyte interface. In this work, we studied the charge of the double layer capacitance at single layer graphene (SLG) electrode used as a model material, in neat (EMIm‐TFSI) and solvated (with acetonitrile) ionic liquid electrodes. The combination of electrochemical impedance spectroscopy and gravimetric electrochemical quartz crystal microbalance (EQCM) measurements evidence that the presence of solvent drastically increases the charge carrier density at the SLG/ionic liquid interface. The capacitance is thus governed not only by the electronic properties of the graphene, but also by the specific organization of the electrolyte side at the SLG surface originating from the strong interactions existing between the EMIm+ cations and SLG surface. EQCM measurements also show that the carbon structure, with the presence of sp2 carbons, affects the charge storage mechanism by favoring counter‐ion adsorption on SLG electrode versus ion exchange mechanism in amorphous porous carbons.
Thermal and mechanical properties of epoxy resin reinforced with modified iron oxide nanoparticles
Authors: Baghdadi Yasmine N. , Youssef Lucia , Bouhadir Kamal , Harb Mohammad , Mustapha Samir , Patra Digambara , Tehrani‐Bagha Ali Reza 
Published: February 2021

AbstractEpoxy polymers, having good mechanical properties and thermal stability, are often used for engineering applications. Their properties can be further enhanced by the addition of iron oxide (Fe3O4) nanoparticles (NPs) as fillers to the resin. In this study, pristine Fe3O4 NPs were functionalized with polydopamine (PDA), (3‐glycidoxypropyl)trimethoxysilane (GPTMS), and (3‐aminopropyl)trimethoxysilane (APTES). X‐ray diffraction and scanning electron microscopy (SEM) were used to study any changes in the crystal structure and size of the NPs while Fourier‐Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) were used to ensure the presence of functional groups on the surface. The mechanical properties of the Fe3O4‐based nanocomposites generally improved except when reinforced with Fe3O4/PDA. The maximum improvement in tensile strength (∼34%) and fracture toughness (∼13%) were observed for pristine Fe3O4‐based nanocomposites. Dynamic mechanical analysis (DMA) showed that the use of any of the treated NPs improved the material's initial storage modulus and had a substantial impact on its dissipation potential. Also, it was observed that the glass transition temperature measurements by DMA and differential scanning calorimetry were below that of pure epoxy. SEM of the cracked surfaces shows that the incorporation of any NPs leads to an enhancement in its thermal and mechanical properties.
Neuronal cell types in the anterior ventral thalamic nucleus of the camel
Authors: Al‐Hussain Saleh M. , Albostanji Shaden A. , Mustafa Ayman G. , Zaqout Sami 
Published: February 2021

AbstractThe anterior ventral nucleus neurons in of the camel brain were morphologically studied by Golgi impregnation method. Two neuronal types of were found in the camel anterior ventral thalamic nucleus, namely, Golgi‐type I neurons and Golgi‐type II neurons. Those neurons were generally similar to their counterparts in the human thalamus. The Golgi‐type I neurons exhibited medium to large cell body (mean diameter = 25 μm) which was either multipolar or triangular in shape. They had from 3 to 10 primary dendrites with many branches but with no spines or appendages. The Golgi‐type II neurons had small to medium size (somatic mean diameter = 17.5 μm), their cell bodies were variable in shape, some were round, and others were multipolar or fusiform. These cells bodies had two to six primary dendrites with few branches that may have spines and/or grape‐like appendages. Our findings shed some light on the anterior ventral thalamic nucleus structure of the camel as one of the strongest adaptive mammals to the hard climatic conditions.
Deconfinement phase transition under chemical equilibrium
Authors: Dexheimer Veronica , Aryal Krishna , Wolf Madison , Constantinou Constantinos , Farias Ricardo L. S. 
Published: February 2021

AbstractIn this work, we investigate how the assumption of chemical equilibrium with leptons affects the deconfinement phase transition to quark matter. This is carried out within the framework of the Chiral Mean Field model allowing for nonzero net strangeness, corresponding to the conditions found in astrophysical scenarios. We build three‐dimensional quantum chromodynamics phase diagrams with temperature, baryon chemical potential, and either charge or isospin fraction or chemical potential to show how the deconfinement region collapses to a line in the special case of chemical equilibrium, such as the one established in the interior of cold catalyzed neutron stars.
Differential Item Functioning Based on Autism Features, IQ, and Age on the Screen for Child Anxiety Related Disorders (SCARED) Among Youth on the Autism Spectrum
Authors: Schiltz Hillary K. , Magnus Brooke E. 
Published: February 2021

Anxiety commonly occurs among youth on the autism spectrum, yet measurement of anxiety in this population is complicated by a number of factors, including potentially overlapping symptomatology, the child's intellectual functioning, and changes in anxiety across development. Moreover, few studies have examined the psychometric properties of anxiety measures in this population, and no study to date has tested whether there are systematic differences in the measurement of anxiety, or differential item functioning (DIF), across the high degree of heterogeneity and the developmental course of autism. To test this possibility, data were combined across multiple studies using the National Database for Autism Research, an NIH‐funded data repository. Parent‐report on the Screen for Child Anxiety Related Disorders (SCARED) and Social Communication Questionnaire (SCQ) were used as measures of anxiety and autism features, respectively. A confirmatory factor analysis indicated good fit of the literature standard five‐factor structure. Moderated nonlinear factor analysis (MNLFA) revealed multiple items with intercept and loading DIF based on level of autism features, IQ, and age, especially for items related to social behavior. Therefore, although the measure's factor structure is consistent with that found in the general population, the SCARED may not capture differences in anxiety equivalently for all children on the spectrum and across their development. Clinicians and researchers need to be especially vigilant in measuring anxiety symptoms in children with autism by removing items flagged for DIF from the SCARED and/or by using multiple measures and informants.Lay AbstractAutistic youth often experience clinical levels of anxiety. Many tools used to measure anxiety were developed for the general population, but not for use with autistic youth. This study found that the Screen for Child Anxiety Related Disorders (SCARED) measures the same five dimensions of anxiety as in the general population. Parents, however, may respond differently to questions on the SCARED based on their child's autism features, intellectual functioning, and age, which impacts our ability to accurately measure anxiety among autistic youth.
Inhibition of emotions in healthy aging: age‐related differences in brain network connectivity
Authors: Almdahl Ina S. , Martinussen Liva J. , Agartz Ingrid , Hugdahl Kenneth , Korsnes Maria S. 
Published: February 2021

AbstractIntroductionSuccessful inhibition of distracting emotions is important for preserving well‐being and daily functioning. There is conflicting evidence regarding the impact of healthy aging on emotional inhibition, and possible age‐related alterations in the neuronal underpinnings of emotional interference processing are unexplored.MethodsThirty younger (mean age 26 years; 15 women) and 30 older (mean age 71 years; 13 women) healthy adults performed a face–word emotional Stroop task while undergoing functional magnetic resonance imaging of the brain. A resting‐state scan was acquired for calculating the amplitude of low‐frequency fluctuations as an estimate of vascular reactivity. Comparisons of brain activation during the task were assessed in a whole‐brain, voxel‐wise analysis, contrasting congruent, and incongruent conditions. The canonical regions of the frontoparietal, salience, dorsal attention, and default mode networks were used as seed regions for assessing functional connectivity within and between large‐scale brain networks. Task performance was evaluated using response accuracy and response time.ResultsThe older adults had longer response times and lower task accuracy than the younger adults, but the emotional interference effect was not significantly different between the groups. Whole‐brain analysis revealed no significant age‐related differences in brain activation patterns. Rescaling the data for estimated variability in vascular reactivity did not affect the results. In older adults, there was relatively stronger functional connectivity with the default mode network, the sensorimotor network, and the dorsal attention network for the frontoparietal and salience network seeds during the task. Conversely, younger adults had relatively stronger connections within and between the frontoparietal and salience networks.ConclusionIn this first fMRI study of emotional Stroop interference in older and younger adults, we found that the emotional interference effect was unchanged in healthy aging and replicated the finding from non‐emotional task studies that older adults have greater between‐network and less within‐network connectivity compared to younger adults.
Climate adaptation within the tourism sector of a small island developing state: A case study from the coastal accommodations subsector in the Bahamas
Authors: Pathak Arsum , van Beynen Philip E. , Akiwumi Fenda A. , Lindeman Kenyon C. 
Published: February 2021

AbstractTourism in Small Island Developing States (SIDS) is vulnerable to climate change. Using the Bahamas as a case study, this study presents findings from a survey administered with property managers from the coastal accommodations sector to identify their adaptation strategies to tackle climate change. We also evaluate their adaptive capacity by developing SIDS‐specific indicators based on a capitals approach. Findings indicate that efforts toward adaptation were limited to disaster preparedness for hurricanes, reflecting a short‐term focus in the face of climate change uncertainties. In addition to the lack of finances and knowledge for incorporating adaptation measures, their capacity to adapt is diminished due to a lack of access to climate change information, skilled staff, and specific climate change planning reflecting limited human and institutional capitals. Recommendations are provided for strategies synergistic with the resilience focus of our paper such as ecosystem‐based adaptation and green jobs. The study informs tourism resilience and adaptation planning in the Bahamas which may apply to other SIDS.
Supplier evaluation in the context of circular economy: A forward step for resilient business and environment concern
Authors: Haleem Abid , Khan Shahbaz , Luthra Sunil , Varshney Harshit , Alam Musaib , Khan Mohd Imran 
Published: February 2021

AbstractResource depletion is a concern for the global economy; many think that available resources on the planet will not be able to cater to an ever‐growing population. Thus, economies are trying to become circular, leaving behind the linear tradition linear approach. In the circular economy (CE), physical resources and energy are made to loop back into the supply chain (SC) for a more extended period. Proper selection of suppliers is an essential criterion towards proper execution of the CE principle in SC. In this research, we have constructed a framework for evaluating the supplier concerning the CE implementation. Further, this research identifies the criterion and sub‐criterion, which are pertinent for evaluating the supplier in CE context. Fuzzy‐based ‘Criteria Importance Through Inter‐Criteria Correlation (CRITIC)’ method is justifiably applied to determine the aggregated weights of the criteria. Finally, ‘Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS)’ method is used to determine the suppliers' ranking in the Indian automobile industry. Six criteria and 24 sub‐criteria are obtained as per recent literature and then inputs from experts. ‘Environment’ criterion came out as the most favourable criterion with a subjective weight of 0.230. The current research is one of the first such attempts to provide criteria for supplier selection in a CE environment. The developed framework would help organisations in implementing CE‐based supplier selection. The identified criteria and sub‐criteria would provide organisations with means to evaluate suppliers and help suppliers develop an effective and efficient CE based on the SC.
Thinking differently about family violence: Shifting from a criminal justice response to a recovery orientation
Authors: Roguski Michael , Edge Kiri 
Published: February 2021

AbstractAgainst a backdrop of increasing rates of family violence in Aotearoa New Zealand, opportunities exist to reflect upon, and critically evaluate, our conventional understanding and responses to family violence. In doing so, there is considerable potential to further develop and progress more efficacious orientations and approaches. The current study sought to explore alternative approaches from the perspectives of 35 men who have engaged in family violence; understanding the type of supports and interventions that have aided their desistance. Participants traced their desistance to family violence to communities of support, communities that have raised awareness of family violence while simultaneously engaging men who either use violence or were at risk of using violence, and the development of holistic, therapeutic, and supportive communities. Themes from these men's narratives highlight the benefits of a move away from a criminogenic response to a community‐embedded recovery orientation.
A Review on Glassy and Rubbery Polymeric Membranes for Natural Gas Purification
Authors: Farnam Marjan , bin Mukhtar Hilmi , bin Mohd Shariff Azmi 
Published: February 2021

AbstractA comprehensive overview of membrane technology used for natural gas purification and other gas separation applications including methods, materials, and results described in previous studies is presented. Different membrane categories are elaborated thoroughly followed by comparisons made between glassy and rubbery polymeric membranes. Various approaches to improve membrane separation performance, such as incorporation of inorganic fillers and blending technique, are discussed. Gas separation in different membranes, e.g., glassy/rubbery polymer blend membranes, mixed matrix membranes, and polymeric blend mixed matrix membranes, are considered. Adopted techniques by researchers to solve existing issues in membrane fabrication and performance are explained in detail.
Arylphosphonate‐Tethered Porphyrins: Fluorescence Silencing Speaks a Metal Language in Living Enterocytes**
Authors: Keil Claudia , Klein Julia , Schmitt Franz‐Josef , Zorlu Yunus , Haase Hajo , Yücesan Gündoğ 
Published: February 2021

AbstractWe report the application of a highly versatile and engineerable novel sensor platform to monitor biologically significant and toxic metal ions in live human Caco‐2 enterocytes. The extended conjugation between the fluorescent porphyrin core and metal ions through aromatic phenylphosphonic acid tethers generates a unique turn off and turn on fluorescence and, in addition, shifts in absorption and emission spectra for zinc, cobalt, cadmium and mercury. The reported fluorescent probes p‐H8TPPA and m‐H8TPPA can monitor a wide range of metal ion concentrations via fluorescence titration and also via fluorescence decay curves. Cu‐ and Zn‐induced turn off fluorescence can be differentially reversed by the addition of common chelators. Both p‐H8TPPA and m‐H8TPPA readily pass the mammalian cellular membrane due to their amphipathic character as confirmed by confocal microscopic imaging of living enterocytes.
Mucopolysaccharidosis (MPS): Review of the literature and case series of five pediatric dental patients
Authors: Hirst Lorna , Mubeen Suhaym , Abou‐Ameira Gehan , Chakrapani Anupam 
Published: February 2021

AbstractPatients with MPS present with a plethora of dental manifestations, accompanying behavioral difficulties and medical comorbidities which often dictate the need for treatment in specialist centers. Prevention is therefore mandatory in this high‐risk group.
Mechanistic Insights for Nitromethane Activation into Reactive Nitrogenating Reagents
Authors: Qu Zheng‐Wang , Zhu Hui , Grimme Stefan 
Published: February 2021

AbstractRecently, it was found that nitromethane (CH3NO2) can be activated into a useful nitrogenating reagent for the synthesis of amide and nitrile compounds. In this work, the mechanisms of CH3NO2 activation are explored in detail by extensive DFT calculations. In aqueous triflic acid (HOTf) solution, the formal 1,3‐H‐shift of CH3NO2 into transient CH2=NO2H is identified as the rate‐limiting step over a barrier of 29.6 kcal/mol, followed by multistep acid hydrolysis to cleave the C=N bond to form NH3OH+ (and HCOOH) as final product. In contrast, in non‐aqueous acetic acid (AcOH) solution with electrophilic Tf2O and nucleophilic HCOOH additives, the C=N bond is cleaved by sequential steps of H2O elimination, electrophilic Tf2O activation, nucleophilic HCOOH addition and acetate/TfO− exchange, affording AcONH3+ as more reactive nitrogenating reagent for Beckmann‐type reactions.