scholarly journals Spin-Dependent Phenomena in Semiconductor Micro-and Nanoparticles—From Fundamentals to Applications

2020 ◽  
Vol 10 (14) ◽  
pp. 4992
Author(s):  
Vladimir M. Fomin ◽  
Victor Yu. Timoshenko
Keyword(s):  
Biomedical Applications ◽  
Crystalline Silicon ◽  
Experimental Results ◽  
Optical Injection ◽  
Electron Spins ◽  
Molecular Systems ◽  
Mechanical Approach ◽  
Magnetic Resonance Imaging Mri ◽  
Quantum Mechanical Approach ◽  
Mri Diagnostics

The present overview of spin-dependent phenomena in nonmagnetic semiconductor microparticles (MPs) and nanoparticles (NPs) with interacting nuclear and electron spins is aimed at covering a gap between the basic properties of spin behavior in solid-state systems and a tremendous growth of the experimental results on biomedical applications of those particles. The first part of the review represents modern achievements of spin-dependent phenomena in the bulk semiconductors from the theory of optical spin orientation under indirect optical injection of carriers and spins in the bulk crystalline silicon (c-Si)—via numerous insightful findings in the realm of characterization and control through the spin polarization—to the design and verification of nuclear spin hyperpolarization in semiconductor MPs and NPs for magnetic resonance imaging (MRI) diagnostics. The second part of the review is focused on the electron spin-dependent phenomena in Si-based nanostructures, including the photosensitized generation of singlet oxygen in porous Si and design of Si NPs with unpaired electron spins as prospective contrast agents in MRI. The experimental results are analyzed by considering both the quantum mechanical approach and several phenomenological models for the spin behavior in semiconductor/molecular systems. Advancements and perspectives of the biomedical applications of spin-dependent properties of Si NPs for diagnostics and therapy of cancer are discussed.

Fragment-based quantum mechanical approach to biomolecules, molecular clusters, molecular crystals and liquids

2020 ◽  
Vol 22 (22) ◽  
pp. 12341-12367 ◽  
Author(s):  
Jinfeng Liu ◽  
Xiao He
Keyword(s):  
Ab Initio ◽  
State Of The Art ◽  
System Size ◽  
Quantum Mechanical ◽  
Molecular Systems ◽  
The Past ◽  
Current State ◽  
Electronic Structure Methods ◽  
Mechanical Approach ◽  
Quantum Mechanical Approach

To study large molecular systems beyond the system size that the current state-of-the-art ab initio electronic structure methods could handle, fragment-based quantum mechanical (QM) approaches have been developed over the past years, and proved to be efficient in dealing with large molecular systems at various ab initio levels.

Quantitative Prediction of Aggregation‐Induced Emission: A Full Quantum Mechanical Approach to the Optical Spectra

2020 ◽  
Vol 132 (28) ◽  
pp. 11647-11652
Author(s):  
Wei Zhang ◽  
Jinfeng Liu ◽  
Xinsheng Jin ◽  
Xinggui Gu ◽  
Xiao Cheng Zeng ◽  
...  
Keyword(s):  
Optical Spectra ◽  
Quantitative Prediction ◽  
Quantum Mechanical ◽  
Aggregation Induced Emission ◽  
Mechanical Approach ◽  
Quantum Mechanical Approach ◽  
Full Quantum

Computational Studies of Magnesium and Strontium Substitution in Hydroxyapatite

2012 ◽  
Vol 529-530 ◽  
pp. 123-128 ◽  
Author(s):  
Flora E. Imrie ◽  
Marta Corno ◽  
Piero Ugliengo ◽  
Iain R. Gibson
Keyword(s):  
Density Functional ◽  
Structural Changes ◽  
Harmonic Approximation ◽  
Site Preference ◽  
Ionic Radii ◽  
Biologically Relevant ◽  
Site Preferences ◽  
Mechanical Approach ◽  
Quantum Mechanical Approach ◽  
Mg Substitution

The properties of hydroxyapatite can be improved by substitution of biologically relevant ions, such as magnesium (Mg) and strontium (Sr), into its structure. Previous work in the literature has not reached agreement as to site preferences in these substitutions, and there are suggestions that these may change with differing levels of substitution. The current work adopted a quantum mechanical approach based on density functional theory using the CRYSTAL09 code to investigate the structural changes relating to, and site preferences of, magnesium and strontium substitution (to 10 mol%) in hydroxyapatites and also to predict the corresponding vibrational spectra in the harmonic approximation. The structures underwent full geometrical optimisation within the P63 space group, indicating an energetic site preference for the Ca (2) site in the case of Mg substitution, and the Ca (1) site in the case of Sr. Shrinkage of the unit cell was observed in the case of Mg substitution, and expansion in the case of Sr substitution, in agreement with the corresponding ionic radii. Thermodynamic properties of the structures obtained from the harmonic vibrational frequency calculations confirmed that the structures were minima on the potential energy surface. Isotopic substitutions indicated that the main contribution of Sr and Mg to vibrational modes is at frequencies < 400 cm-1.

Comment on: “On the standard quantum-mechanical approach to times of arrival”

2003 ◽  
Vol 313 (5-6) ◽  
pp. 498-501 ◽  
Author(s):  
I.L. Egusquiza ◽  
J.G. Muga ◽  
B. Navarro ◽  
A. Ruschhaupt
Keyword(s):  
Quantum Mechanical ◽  
Standard Quantum ◽  
Mechanical Approach ◽  
Quantum Mechanical Approach

scholarly journals Magnetite-Silica Core/Shell Nanostructures: From Surface Functionalization towards Biomedical Applications—A Review

2021 ◽  
Vol 11 (22) ◽  
pp. 11075
Author(s):  
Angela Spoială ◽  
Cornelia-Ioana Ilie ◽  
Luminița Narcisa Crăciun ◽  
Denisa Ficai ◽  
Anton Ficai ◽  
...  
Keyword(s):  
Magnetite Nanoparticles ◽  
Biomedical Applications ◽  
Sol Gel ◽  
Magnetic Nanomaterials ◽  
Core Shell ◽  
Synthesis Methods ◽  
Shell Nanostructures ◽  
Silica Core ◽  
Magnetic Resonance Imaging Mri ◽  
Co Precipitation

The interconnection of nanotechnology and medicine could lead to improved materials, offering a better quality of life and new opportunities for biomedical applications, moving from research to clinical applications. Magnetite nanoparticles are interesting magnetic nanomaterials because of the property-depending methods chosen for their synthesis. Magnetite nanoparticles can be coated with various materials, resulting in “core/shell” magnetic structures with tunable properties. To synthesize promising materials with promising implications for biomedical applications, the researchers functionalized magnetite nanoparticles with silica and, thanks to the presence of silanol groups, the functionality, biocompatibility, and hydrophilicity were improved. This review highlights the most important synthesis methods for silica-coated with magnetite nanoparticles. From the presented methods, the most used was the Stöber method; there are also other syntheses presented in the review, such as co-precipitation, sol-gel, thermal decomposition, and the hydrothermal method. The second part of the review presents the main applications of magnetite-silica core/shell nanostructures. Magnetite-silica core/shell nanostructures have promising biomedical applications in magnetic resonance imaging (MRI) as a contrast agent, hyperthermia, drug delivery systems, and selective cancer therapy but also in developing magnetic micro devices.

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