197,195 research outputs found
Mixed d-f Block Single-Molecule Toroics
No full textSingle Molecule Toroics pp 15–66Cite as
Mixed d-f Block Single-Molecule Toroics
Keith S. Murray, Stuart K. Langley, Kuduva R. Vignesh, Gopalan Rajaraman, Kieran Hymas & Alessandro Soncini
Chapter
First Online: 24 November 2022
3 Accesses
Abstract
In this chapter, we focus on the single-molecule toroidal (SMT) behaviour of a family of “double dysprosium triangle” heptanuclear species which contain a bridging d-block M(III) or a p-block M(III) ion. They are of general formula [MIIIDyIII 6(OH)8(o-tol)12(NO3)(MeOH)5]∙3MeOH, labelled MDy 6, where o-tol = o-toluate. The parent compound has M = Cr, with subsequent family members having M = Mn, Fe, Co and Al, the latter two having diamagnetic M(III) centres. This heptanuclear family could also be made using chloride as counter-anion rather than nitrate, the molecular structures being similar to the nitrates though the unit cells are different. The LnIII ion could also be varied to include Tb, Ho and Er and, thus, allow exploration of SMT behaviour in non-Dy analogues. The syntheses, structures and magnetic and EPR properties are described, starting with the parent CrDy 6. Theoretical calculations are described in detail, with MOLCAS methods employed to determine anisotropy directions, blocking barriers and relaxation effects and a newly developed model used to calculate magnetically coupled toroidal states and the role of these states in spin dynamics. The direct simulation of the micro-Squid magnetic hysteresis loops of all family members is described as well as that of the original Dy 3 material. Toroido-structural correlations are presented with strategies developed to optimize the important ferrotoroidic coupling between Dy3 triangles in these heptanuclear toroidal species. Finally, we give a brief summary of SMT behaviour in ring-shaped 3d-4f toroidal species
Tetrastemma freyae Chernyshev & Polyakova & Vignesh & Jain & Sanjeevi & Norenburg & Rajesh 2020, sp. nov.
No full textTetrastemma freyae sp. nov. (Fig. 1 A–G) Type material. Holotype No JLN1622.01 (NMNH), Kaneohe Bay, Oahu, Hawaii, July 2017, depth 3 m, live corals, coll. J.L. Norenburg. Paratype JLN1622.02 (NMNH), collected with holotype. Paratype No ZSI / MBRC /NE-356 (ZSI), Covelong (Kovalam) beach (12.7925ºN, 80.2530ºE), Tamil Nadu, India, mussel beds, intertidal, 16 December 2019, coll. M.S. Vignesh. Other material examined. Three specimens, Covelong (Kovalam), Tamil Nadu, India, mussel beds, intertidal, 21 February 2019. GenBank accession numbers. Holotype MT 247877 (COI), MT 247879 (H3); paratype MT 247878 (COI), MT 247880 (H3). Description. External features. Live specimens 2–5 сm long and up to 1 mm wide, with spatulate- to diamondshaped head, bearing four black eyes. Two anterior eyes not distinguishable being masked by patch of cephalic pigment. Oblique cephalic furrows in two pairs: posterior furrows located behind posterior pair of eyes and anterior pair immediately in front of posterior eyes. Body tapering posteriorly, with blunt-rounded tail. General body color pale yellowish, with a patch of black pigment on dorsal surface of head. Patch trapezoid or oval, slightly varying in shape between specimens. Deeply located white pigment (possibly cephalic glands) present near anterior and posterior margins of patch. Some specimens bear small irregularly spaced black spots located dorsally. In holotype, lateral gut pouches visible as two darker lines. Internal features (on squeezed live specimens). Rhynchocoel as long as body. Basis cylindrical, with truncated and widened posterior part, 105 µm long and 35 µm in maximum width; central stylet 80 µm long. Two accessory stylet pouches each containing two accessory stylets. Gut pouches deeply branched. Ovaries contain 1–2 ovules. Remarks. A total of 16 described Tetrastemma species have a pale general body color and a dark patch of pigment on the dorsal surface of the head. Four of these, Tetrastemma verinigrum Iwata, 1954, T. pseudocoronatum Chernyshev, 1998, T. pimaculatum Chernyshev, 1998, and T. olgarum Chernyshev, 1998, have been recorded from Asian waters. Some varieties of Tetrastemma nigrifrons (Coe, 1904) (formerly placed in Quasitetrastemma – see Chernyshev 2004) also have a similar color (see Zaslavskaya et al. 2010). These species possess pear- or ovalshaped basis of the central stylet, whereas the basis in the new species is cylindrical with a flared posterior margin. A similar basis is characteristic for species in the genus Zygonemertes Montgomery, 1897, as well as Tetrastemma albomaculatum Chernyshev, 2016. The latter species, unlike T. freyae, has a white spot on the head (Chernyshev 2016). As the obtained data show, not only the body color, but also the shape of the central stylet basis should be taken into account in ‘histology-free’ descriptions of the new species of Tetrastemma. DNA barcode analysis. Among the Pacific Tetrastemma species with a dark pigment patch on the head, COI sequences are known for T. pseudocoronatum, T. pimaculatum, T. olgarum, and T. nigrifrons. The p -distances be- tween these species and T. melanocephalum from the European coast are provided in Table 1. The samples of T. freyae from Hawaii and India have p -distances 1.3% for COI and 0.3% for H3, which warrant designating a single species despite the substantial geographical space between these findings. Etymology. The specific epithet honors Ms Freya Goetz (NMNH) for her invaluable assistance to JLN in support of his field and laboratory work.Published as part of Chernyshev, Alexei V., Polyakova, Neonila E., Vignesh, Mohandhas S., Jain, Ruchi P., Sanjeevi, Prakash, Norenburg, Jon L. & Rajesh, Rajaian P., 2020, A histology-free description of a new species of the genus Tetrastemma (Nemertea: Hoplonemertea: Monostilifera) from Hawaii and India, pp. 379-383 in Zootaxa 4808 (2) on pages 380-382, DOI: 10.11646/zootaxa.4808.2.10, http://zenodo.org/record/393345
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sj-docx-2-pie-10.1177_09544089231190200 - Supplemental material for Experimental investigation to optimize machining parameters for super duplex stainless steel in spark EDM using die-sinking and MQL system
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"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
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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
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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
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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
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