Colloidal magnetic nanocrystal clusters: variable length-scale interaction mechanisms, synergetic functionalities and technological advantages

AbstractMagnetic particles of optimized nanoscale dimensions can be utilized as building blocks to generate colloidal nanocrystal assemblies with controlled size, well-defined morphology, and tailored properties. Recent advances in the state-of-the-art surfactant-assisted approaches for the directed aggregation of inorganic nanocrystals into cluster-like entities are discussed, and the synthesis parameters that determine their geometrical arrangement are highlighted. This review pays attention to the enhanced physical properties of iron oxide nanoclusters, while it also points to their emerging collective magnetic response. The current progress in experiment and theory for evaluating the strength and the role of intra- and inter-cluster interactions is analyzed in view of the spatial arrangement of the component nanocrystals. Numerous approaches have been proposed for the critical role of dipole-dipole and exchange interactions in establishing the nature of the nanoclusters’ cooperative magnetic behavior (be it ferromagnetic or spin-glass like). Finally, we point out why the purposeful engineering of the nanoclusters’ magnetic characteristics, including their surface functionality, may facilitate their use in diverse technological sectors ranging from nanomedicine and photonics to catalysis.

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The critical role of next-nearest-neighbor interlayer interaction in the magnetic behavior of magnetic/non-magnetic multilayers

New Journal of Physics ◽

10.1088/1367-2630/15/12/123025 ◽

2013 ◽

Vol 15 (12) ◽

pp. 123025 ◽

Cited By ~ 6

Author(s):

Sunjae Chung ◽

Sangyeop Lee ◽

Taehee Yoo ◽

Hakjoon Lee ◽

J-H Chung ◽

...

Keyword(s):

Nearest Neighbor ◽

Critical Role ◽

Magnetic Behavior ◽

Magnetic Multilayers ◽

Interlayer Interaction

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The Intersection of Purine and Mitochondrial Metabolism in Cancer

Cells ◽

10.3390/cells10102603 ◽

2021 ◽

Vol 10 (10) ◽

pp. 2603

Author(s):

Humberto De Vitto ◽

Danushka B. Arachchige ◽

Brian C. Richardson ◽

Jarrod B. French

Keyword(s):

Ovarian Cancer ◽

Cell Growth ◽

Cancer Progression ◽

Critical Role ◽

Building Blocks ◽

Mitochondrial Metabolism ◽

Growth And Survival ◽

Dna And Rna ◽

Purines And Pyrimidines

Nucleotides are essential to cell growth and survival, providing cells with building blocks for DNA and RNA, energy carriers, and cofactors. Mitochondria have a critical role in the production of intracellular ATP and participate in the generation of intermediates necessary for biosynthesis of macromolecules such as purines and pyrimidines. In this review, we highlight the role of purine and mitochondrial metabolism in cancer and how their intersection influences cancer progression, especially in ovarian cancer. Additionally, we address the importance of metabolic rewiring in cancer and how the evolving landscape of purine synthesis and mitochondria inhibitors can be potentially exploited for cancer treatment.

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Directed assembly of magnetic and semiconducting nanoparticles with tunable and synergistic functionality

Scientific Reports ◽

10.1038/s41598-019-52154-0 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Mark Bartolo ◽

Jussi J. Amaral ◽

Linda S. Hirst ◽

Sayantani Ghosh

Keyword(s):

Liquid Crystalline ◽

Critical Role ◽

Directed Assembly ◽

Building Blocks ◽

Design And Synthesis ◽

Transmission Electron ◽

20 Nm ◽

Microscopy Characterization

Abstract The ability to fabricate new materials using nanomaterials as building blocks, and with meta functionalities, is one of the most intriguing possibilities in the area of materials design and synthesis. Semiconducting quantum dots (QDs) and magnetic nanoparticles (MNPs) are co-dispersed in a liquid crystalline (LC) matrix and directed to form self-similar assemblies by leveraging the host’s thermotropic phase transition. These co-assemblies, comprising 6 nm CdSe/ZnS QDs and 5–20 nm Fe3O4 MNPs, bridge nano- to micron length scales, and can be modulated in situ by applied magnetic fields <250 mT, resulting in an enhancement of QD photoluminescence (PL). This effect is reversible in co-assemblies with 5 and 10 nm MNPs but demonstrates hysteresis in those with 20 nm MNPs. Transmission electron microscopy (TEM) and energy dispersive spectroscopy reveal that at the nanoscale, while the QDs are densely packed into the center of the co-assemblies, the MNPs are relatively uniformly dispersed through the cluster volume. Using Lorentz TEM, it is observed that MNPs suspended in LC rotate to align with the applied field, which is attributed to be the cause of the observed PL increase at the micro-scale. This study highlights the critical role of correlating multiscale spectroscopy and microscopy characterization in order to clarify how interactions at the nanoscale manifest in microscale functionality.

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Atomic-layer Rashba-type superconductor protected by dynamic spin-momentum locking

Nature Communications ◽

10.1038/s41467-021-21642-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Shunsuke Yoshizawa ◽

Takahiro Kobayashi ◽

Yoshitaka Nakata ◽

Koichiro Yaji ◽

Kenta Yokota ◽

...

Keyword(s):

Critical Role ◽

Exchange Interactions ◽

Atomic Layer ◽

Critical Magnetic Field ◽

Convincing Evidence ◽

Fermi Surfaces ◽

Dynamic Spin ◽

Breaking Parameter ◽

Spin Momentum

AbstractSpin-momentum locking is essential to the spin-split Fermi surfaces of inversion-symmetry broken materials, which are caused by either Rashba-type or Zeeman-type spin-orbit coupling (SOC). While the effect of Zeeman-type SOC on superconductivity has experimentally been shown recently, that of Rashba-type SOC remains elusive. Here we report on convincing evidence for the critical role of the spin-momentum locking on crystalline atomic-layer superconductors on surfaces, for which the presence of the Rashba-type SOC is demonstrated. In-situ electron transport measurements reveal that in-plane upper critical magnetic field is anomalously enhanced, reaching approximately three times the Pauli limit at T = 0. Our quantitative analysis clarifies that dynamic spin-momentum locking, a mechanism where spin is forced to flip at every elastic electron scattering, suppresses the Cooper pair-breaking parameter by orders of magnitude and thereby protects superconductivity. The present result provides a new insight into how superconductivity can survive the detrimental effects of strong magnetic fields and exchange interactions.

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Magneto-mechanical coupling of single domain particles in soft matter systems

Physical Sciences Reviews ◽

10.1515/psr-2019-0092 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Julian Seifert ◽

Karin Koch ◽

Melissa Hess ◽

Annette M. Schmidt

Keyword(s):

Soft Matter ◽

Magnetic Particles ◽

Biological Fluids ◽

Magnetic Behavior ◽

Structure Property ◽

Mechanical Coupling ◽

Surface Functionality ◽

Structure Property Relationships ◽

Recent Advancement ◽

Insight Into

Abstract Combining inorganic magnetic particles with complex soft matrices such as liquid crystals, biological fluids, gels, or elastomers, allows access to a plethora of magnetoactive effects that are useful for sensing and actuation perspectives, allowing inter alia to explore and manipulate material properties on the nanoscale. The article provides a comprehensive summary of recent advancement on employing magnetic nanoparticles either as tracers for dynamic processes, or as nanoscopic actuating units. By variation of the particle characteristics in terms of size, shape, surface functionality, and magnetic behavior, the interaction between the probe or actuator particles and their environment can be systematically tailored in wide ranges, giving insight into the relevant structure–property relationships.

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Magnetodeformational Anisotropy of FeGa/PU Hybrid Nanocomposite via Particle Concentration and Spatial Orientation

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.233-234.607 ◽

2015 ◽

Vol 233-234 ◽

pp. 607-610

Author(s):

Tatiana Yu. Kiseleva ◽

Sergey I. Zholudev ◽

Alla A. Novakova ◽

Tatiana S. Gendler ◽

Igor A. Il’inych ◽

...

Keyword(s):

Magnetic Particles ◽

Volume Fraction ◽

Magnetic Behavior ◽

Spatial Arrangement ◽

Mechanical Analysis ◽

Interparticle Interactions ◽

Dynamical Mechanical Analysis ◽

Alloy Particles ◽

Structure Morphology ◽

Matrix Correlation

The present work has been undertaken to research effects of structure, morphology, volume fraction, spatial arrangement of magnetostrictive intermetallic FeGa alloy particles dispersed in modified polyurethane matrix. Correlation of composite magnetic behavior with structure and mechanical properties has been obtained by measurements of magnetostriction, remanent magnetization anisotropy, SEM, and dynamical mechanical analysis. Anisotropic chain structures of magnetic particles within the polymer with different interparticle interactions were observed. The increase of the magnetostrictive response with tailor-made magnetic anisotropy induced by magnetic particles volume fraction has been demonstrated

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Augmin regulates kinetochore tension and spatial arrangement of spindle microtubules by nucleating bridging fibers

10.1101/2020.09.10.291740 ◽

2020 ◽

Cited By ~ 2

Author(s):

Martina Manenica ◽

Valentina Štimac ◽

Isabella Koprivec ◽

Juraj Simunić ◽

Iva M. Tolić

Keyword(s):

Critical Role ◽

Spatial Arrangement ◽

Knock Out ◽

Daughter Cells ◽

Sister Kinetochore ◽

Division Spindle ◽

Spindle Microtubules ◽

Bridging Fibers ◽

Poleward Flux

ABSTRACTThe mitotic spindle functions as a molecular micromachine that evenly distributes chromosomes into two daughter cells during cell division. Spindle microtubules in human cells are mainly nucleated at the centrosome and on the lateral surface of existing microtubules by the augmin complex. However, it is unknown how the augmin-mediated nucleation affects functionally distinct microtubule bundles and consequently the forces within the spindle. Here we show, by using siRNA depletion and CRISPR knock-out of the augmin complex subunits HAUS6 or HAUS8, that augmin is crucial for the nucleation of bridging microtubules, which laterally link sister kinetochore fibers. Augmin depletion resulted in a reduction in the number of microtubules within bridging fibers by around 80% and in kinetochore fibers by 40%, suggesting that the bridging microtubules are mainly nucleated at the surface of present microtubules. In augmin-depleted cells, the interkinetochore distance decreased preferentially for kinetochores that lack a bridging fiber, independently of the thickness of their k-fibers, implying that augmin affects forces on kinetochores largely via bridging fibers. Without augmin the number of bridging fibers decreased, with the remaining ones mostly confined to the spindle periphery with an increased overlap length. A slower poleward flux of microtubules after augmin depletion is indicative of slower sliding within the bridging fiber. Our results demonstrate a critical role of augmin in the formation of bridging microtubules and proper architecture of the metaphase spindle, suggesting a model where sliding of augmin-nucleated bridging microtubules promotes poleward flux of k-fibers and thus tension on kinetochores.

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The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

Perspectives on Language Learning and Education ◽

10.1044/lle15.2.50 ◽

2008 ◽

Vol 15 (2) ◽

pp. 50-59 ◽

Cited By ~ 1

Author(s):

Amy Philofsky

Keyword(s):

Language Development ◽

Critical Role ◽

Children With Autism ◽

Autism Spectrum ◽

Children With Asd ◽

Prevalence Estimates ◽

Notable Increase ◽

Screening Assessment ◽

Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

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