Properties of magnetic nanodots with perpendicular anisotropy

Nanodots with magnetic vortices have many potential applications, such as magnetic memories (VRAMs) and spin transfer nano-oscillators (STNOs). Adding a perpendicular anisotropy term to the magnetic energy of the nanodot it becomes possible to tune the vortex core properties. This can be obtained, e.g., in Co nanodots by varying the thickness of the Co layer in a Co/Pt stack. Here we discuss the spin configuration of circular and elliptical nanodots for different perpendicular anisotropies; we show for nanodisks that micromagnetic simulations and analytical results agree. Increasing the perpendicular anisotropy, the vortex core radii increase, the phase diagrams are modified and new configurations appear; the knowledge of these phase diagrams is relevant for the choice of optimum nanodot dimensions for applications. MFM measurements on Co/Pt multilayers confirm the trend of the vortex core diameters with varying Co layer thicknesses.Comment: 7 pages, 8 figure

Enhancement of fracture healing in the rat, modulated by compounds that stimulate inducible nitric oxide synthase: Acceleration of fracture healing via inducible nitric oxide synthase.

OBJECTIVES: We investigated the effects on fracture healing of two up-regulators of inducible nitric oxide synthase (iNOS) in a rat model of an open femoral osteotomy: tadalafil, a phosphodiesterase inhibitor, and the recently reported nutraceutical, COMB-4 (consisting of L-citrulline, Paullinia cupana, ginger and muira puama), given orally for either 14 or 42 days. MATERIALS AND METHODS: Unilateral femoral osteotomies were created in 58 male rats and fixed with an intramedullary compression nail. Rats were treated daily either with vehicle, tadalafil or COMB-4. Biomechanical testing of the healed fracture was performed on day 42. The volume, mineral content and bone density of the callus were measured by quantitative CT on days 14 and 42. Expression of iNOS was measured by immunohistochemistry. RESULTS: When compared with the control group, the COMB-4 group exhibited 46% higher maximum strength (t-test, p = 0.029) and 92% higher stiffness (t-test, p = 0.023), but no significant changes were observed in the tadalafil group. At days 14 and 42, there was no significant difference between the three groups with respect to callus volume, mineral content and bone density. Expression of iNOS at day 14 was significantly higher in the COMB-4 group which, as expected, had returned to baseline levels at day 42. CONCLUSION: This study demonstrates an enhancement in fracture healing by an oral natural product known to augment iNOS expression.Cite this article: R. A. Rajfer, A. Kilic, A. S. Neviaser, L. M. Schulte, S. M. Hlaing, J. Landeros, M. G. Ferrini, E. Ebramzadeh, S-H. Park. Enhancement of fracture healing in the rat, modulated by compounds that stimulate inducible nitric oxide synthase: Acceleration of fracture healing via inducible nitric oxide synthase. Bone Joint Res 2017:6:-97. DOI: 10.1302/2046-3758.62.BJR-2016-0164.R2

Performance measurement of cross-culture supply chain partnership: a case study in the Chinese automotive industry

This study explores a performance measurement system for a dynamic supply chain partnership in a cross-cultural context. An initial framework is constructed by reviewing the existing literature, followed by an in-depth case study in the Chinese automotive industry, where the framework is refined to address the multi-cultural setting. A performance measurement, system which includes the relationship strategy and operational measurement criteria for a supply chain partnership, has been developed. The relationship strategy contains elements of strategy orientation, management style, interdependence, mutual organisational characteristics and common goals. The operational measurement criteria consist of commitment, trust, communication behaviour, information sharing, participation decision, quality, production performance, delivery, cost, supplier strength, attitude, compromise and loyalty. The last three operational measurement criteria are found to be particularly relevant to the cross-cultural feature. While existing studies tend to focus on either specific measures or individual organisations, this paper for the first time proposes a comprehensive framework to measure the performance of supply chain partnerships. The cross-cultural perspective provides a further unique view on how a performance measurement system can be responsive to the dynamics in practice

Omnidirectional flat bands in chiral magnonic crystals

The magnonic band structure of two-dimensional chiral magnonic crystals is theoretically investigated. The proposed metamaterial involves a three-dimensional architecture, where a thin ferromagnetic layer is in contact with a two-dimensional periodic array of heavy-metal square islands. When these two materials are in contact, an anti-symmetric exchange coupling known as the Dzyaloshinskii–Moriya interaction (DMI) arises, which generates nonreciprocal spin waves and chiral magnetic order. The Landau–Lifshitz equation and the plane-wave method are employed to study the dynamic magnetic behavior. A systematic variation of geometric parameters, the DMI constant, and the filling fraction allows the examination of spin-wave propagation features, such as the spatial profiles of the dynamic magnetization, the isofrequency contours, and group velocities. In this study, it is found that omnidirectional flat magnonic bands are induced by a sufficiently strong Dzyaloshinskii–Moriya interaction underneath the heavy-metal islands, where the spin excitations are active. The theoretical results were substantiated by micromagnetic simulations. These findings are relevant for envisioning applications associated with spin-wave-based logic devices, where the nonreciprocity and channeling of the spin waves are of fundamental and practical scientific interest

Agroecosystem and rural tourism: Bibliometric analysis and its conceptual relationship from 2014 to 2020

Objective: Analyze scientific papers close linked to the concepts of agroecosystems, rural tourism and its conceptual relationship. Design/methodology/approach: A search of papers published from 2014 up to 2020 in Science Direct (https://www.sciencedirect.com) was conducted, using key words related to the agroecosystem concept and rural tourism. Later, a bibliometric and text analysis was performed. Results: The concept of agroecosystems has been dynamic through time and related to other disciplines. However, research relating this concept with rural tourism is scarce. Limitations of the study/implication: Research proposals on agroecosystems associated to rural tourism are limited. Findings/Conclusions: Papers with the conceptual evolution of agroecosystems integrating rural tourism are scarce. So, it is suggested to study the agroecosystem in its different aspects, but considering their cultural and historical basis.Objective: Analyze scientific papers close linked to the concepts of agroecosystems, rural tourism and its conceptual relationship. Design/methodology/approach: A search of papers published from 2014 up to 2020 in Science Direct (https://www.sciencedirect.com) was conducted, using key words related to the agroecosystem concept and rural tourism. Later, a bibliometric and text analysis was performed. Results: The concept of agroecosystems has been dynamic through time and related to other disciplines. However, research relating this concept with rural tourism is scarce. Limitations of the study/implication: Research proposals on agroecosystems associated to rural tourism are limited. Findings/Conclusions: Papers with the conceptual evolution of agroecosystems integrating rural tourism are scarce. So, it is suggested to study the agroecosystem in its different aspects, but considering their cultural and historical basi

Versatile Coordination of Cyclopentadienyl-Arene Ligands and Its Role in Titanium-Catalyzed Ethylene Trimerization

Cationic titanium(IV) complexes with ansa-(η5-cyclopentadienyl,η6-arene) ligands were synthesized and characterized by X-ray crystallography. The strength of the metal-arene interaction in these systems was studied by variable-temperature NMR spectroscopy. Complexes with a C1 bridge between the cyclopentadienyl and arene moieties feature hemilabile coordination behavior of the ligand and consequently are active ethylene trimerization catalysts. Reaction of the titanium(IV) dimethyl cations with CO results in conversion to the analogous cationic titanium(II) dicarbonyl species. Metal-to-ligand backdonation in these formally low-valent complexes gives rise to a strongly bonded, partially reduced arene moiety. In contrast to the η6-arene coordination mode observed for titanium, the more electron-rich vanadium(V) cations [cyclopentadienyl-arene]V(NiPr2)(NC6H4-4-Me)+ feature η1-arene binding, as determined by a crystallographic study. The three different metal-arene coordination modes that we experimentally observed model intermediates in the cycle for titanium-catalyzed ethylene trimerization. The nature of the metal-arene interaction in these systems was studied by DFT calculations.