196,732 research outputs found
Dissociable functional roles of the human action-observation network (Commentary on E. S. Cross et al.)
No full textDental occlusion after Veau-Wardill-Kilner versus minimal incision technique repair of isolated clefts of the hard and soft palate
No full textOBJECTIVE: To compare the Veau-Wardill-Kilner technique with a technique similar to the minimal incision technique described by Mendosa et al. on the basis of surgical complications and dentoalveolar status in the deciduous dentition. DESIGN: Retrospective study of medical and dental records and casts. PATIENTS: A consecutive series of 129 Caucasian children born with isolated cleft palate between 1980 and 1992. MAIN OUTCOME MEASURES: From medical records, the variables of time for surgery, blood loss, complications in the immediate postoperative period, and frequency of fistulas were evaluated. On dental casts, the variables of sagittal, transversal, and vertical relations; structure of the palatal mucosa; and height of the palatal vault were studied. RESULTS: Time for surgery was shorter in the extensive clefts repaired with a Veau-Wardill-Kilner technique. Blood loss was higher using the Veau-Wardill-Kilner technique. The width of the upper jaw was significantly narrower in the Veau-Wardill-Kilner group, compared with the minimal incision group. Scar tissue and pits of the palate were more frequently found in the Veau-Wardill-Kilner group. CONCLUSIONS: The minimal incision technique in this study has been shown to result in better development of the upper jaw with a better dental occlusion and palatal mucosa with significantly less scar tissue
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Studies of nickel (II) diphosphine complexes directed towards carbon monoxide/ethene catalysis
No full textThe thesis is concerned with the synthesis, characterisation and reactivity of a variety of nickel(II) diphosphine complexes considered possible catalyst precursors for the copolymerisation of CO and ethene. [Ni(diphos)(o-tolyl)(py)]Y (1), [Ni(diphos)(_2)](Y)(_2) (2), and [Ni(diphos)(S)(_2)](Y)(_2) (3) {Y = OTs, OTf} are found to be catalyst precursors for the CO/ethene reaction (115 C, 1200psi, 1:1 CO: ethene) with high selectivity to polyketone formation, the activity depending on the phosphine ligand employed. However, the activity is low and attributed in part to the formation of the [Ni(diphos)(CO)(_2)] (4) complexes which are stable under the reaction conditions. The diphosphine hgand employed, particularly the nature of the backbone, is found to influence the synthesis and reaction chemistry of the complexes (1), (2) and (3).A series of complexes of the type [Ni(R(_2)P(CH(_2))(_a)PR(_2))(o-tolyl)Br] (5) {n = 2; R = Ph, Cy, 'Bu) have been synthesised and the complex [Ni(dppe)(o-tolyl)Cl] has been characterised by X-ray crystaliography. The influence of the chelating diphosphine on the structural characteristics and NMR parameters of these compounds has been investigated. When n > 2 the complexes of the type [Ni(diphos)(o-tolyl)X] were not isolated. The reaction of type (5) complexes with TIY (Y = OTs, BF(_4)) in pyridine led to the formation of complexes of the type [Ni(diphos)(o-tolyl)(py)]Y (1).A series of complexes of the type [Ni(diphos)Cl(_2)] (6) {diphos = dope, dBpe, dcpn} have been synthesised and characterised by X-ray crystallography. The influence of the chelating phosphine ligand on structural characteristics of these compounds has been investigated. Complexes of the type (2) and (3) can be synthesised from type (6) complexes. Detailed studies on the behaviour of a series of complexes of the type [Ni(diphos)(_2)](Y)(_2) (2) and [Ni(diphos)(Y)(_2)] (3) {Y = OTs and OTf), and the equilibrium between them in solution have been undertaken. The complex [Ni(dppe)(-2)](OTs)(_2) has been characterised by X-ray crystallography
Phase-separating Active Materials in Lithium-ion Batteries: Implications for Fast-charging and Material Characterisation
No full textSome active materials used in lithium-ion battery (LIB) electrodes undergo phase separation into Li-rich and Li-poor phases upon lithium intercalation. Typical examples include LiFePO4 (LFP) at the cathode and graphite at the anode. While phase separation enables useful features, such as a constant equilibrium potential as a function of state-of-charge, such behaviour poses challenges during material characterisation and for high-rate operation.
This study provides a perspective of phase separation in LIB active materials by combining non-equilibrium thermodynamics principles [1] with in-operando techniques [2]. The results show that classical techniques used to estimate solid-state diffusion coefficients, such as the galvanostatic intermittent titration technique (GITT) [3], must be revisited for this class of materials. In fact, although the rapid equilibration of the interface between Li-rich and Li-poor phases within a particle leads to a quick voltage relaxation, the solid-state diffusivity can be significantly lower than what this fast dynamics may suggest. This has significant implications on the distribution of lithium within secondary particles because, upon fast lithiation, the Li-rich phase grows at the particle surface and prevents further lithiation. This is especially critical for graphite anodes, since the Li-rich phase (also known as stage I) at the particle surface is the primary cause for the plating of metallic lithium outside the particle, as quantified in in-operando experiments [2]. Nevertheless, experiments also show that Li plating is not irreversible and part of the plated lithium can be stripped and back-intercalated in graphite when the current is interrupted. This discovery opens opportunities for alternative fast-charging protocols as long as the particle size distribution is well controlled to prevent excessive plating on small particles. On the other hand, experimental characterisation and simulation of a disordered carbon, which does not undergo phase separation, reveal an effectively faster solid-state diffusion and a more significant resistance to lithium plating even at high C-rate [4], thus enabling for a comprehensive comparison between solid-solution and phase-separating active materials when it comes to characterisation and fast-charging capabilities.
References
[1] 10.1021/ar300145c. Bazant, M.Z. Theory of Chemical Kinetics and Charge Transfer Based on Nonequilibrium Thermodynamics. Acc. Chem. Res. 2013, 46, 1144-1160
[2] 10.1038/s41467-023-40574-6. Lu, X.; Lagnoni, M.; Bertei, A.; Das, S.; Owen, R.E.; Li, Q.; O'Regan, K.; Wade, A.; Finegan, D.P.; Kendrick, E.; Bazant, M.Z.; Brett, D.J.L.; Shearing, P.R. Multiscale Dynamics of Charging and Plating in Graphite Electrodes Coupling Operando Microscopy and Phase-field Modelling. Nat. Commun. 2023, 14, 5127
[3] 10.1149/1.2133112. Weppner, W.; Huggins, R.A. Determination of the Kinetic Parameters of Mixed-Conducting Electrodes and Application to the System Li3Sb. J. Electrochem. Soc. 1977, 124, 1569-1578
[4] 10.1021/acsaem.3c01280. Ahn, S.; Lagnoni, M.; Yuan, Y.; Ogarev, A.; Vavrinyuk, E.; Voynov, G.; Barrett, E.; Pelli, A.; Atrashchenko, A.; Platonov, A.; Gurevich, S.; Gorokhov, M.; Rupasov, D.; Robertson, A.W.; House, R.A.; Johnson, L.R.; Bertei, A.; Chernyshov, D.V. Chemical Origins of a Fast-Charge Performance in Disordered Carbon Anodes. ACS Appl. Energy Mater. 2023, 6, 8455-8465
Acknowledgements
This study received funding from the National Recovery and Resilience Plan, Mission 4 Component 2 Investment 1.3 - Call for tender No. 1561 of 11.10.2022 of Ministero dell’Università e della Ricerca, according to attachment E of Decree No. 1561/2022, Project title “Network 4 Energy Sustainable Transition – NEST”, CUP I53C22001450006; funded by the European Union–NextGenerationEU. This paper reflects only the authors’ views and opinions; neither the European Union nor the European Commission can be considered responsible for them
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