Publications by authors named "Lofland S"

Article Synopsis
  • Non-contact in situ techniques, like low-frequency Raman spectroscopy, can enhance resin formulation and processing by effectively monitoring cure kinetics.
  • Recent studies reveal a connection between structural conversion, related to rheological properties, and chemical conversion, although the latter shows no direct correlation in their data.
  • The research successfully combines structural and chemical conversion data to create master cure kinetics curves, linking them with a semi-empirical model for storage shear modulus as curing progresses.
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  • Understanding how resin cures is vital for linking the properties of polymers to their processing and structure.
  • The Raman spectrum's disorder band indicates changes in material characteristics as resin polymerizes, which can be normalized to track structural conversion kinetics versus chemical conversion kinetics.
  • Our findings show that while structural and chemical conversions happen at the same time during the primary network formation, there is a delay between them in the secondary network formation.
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  • The substitution of Ru by Ta in SrYbRuO leads to changes in its magnetic properties, showing stronger antiferromagnetic interactions in pure SrYbRuO compared to its Ta-substituted variants.
  • As the concentration of Ta increases, the band gap of the material increases nearly linearly, indicating shifts in electronic structure and orbital ordering.
  • The photoelectrocatalytic studies reveal that SrYbRuO has the highest photocurrent density and optimal performance for oxygen evolution reactions, with structural insights gained from techniques like XPS and EPR confirming the oxidation states and the presence of oxygen vacancies.
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Despite considerable advances in recent years, challenges in delivery and storage of biological drugs persist and may delay or prohibit their clinical application. Though nanoparticle-based approaches for small molecule drug encapsulation are mature, encapsulation of proteins remains problematic due to destabilization of the protein. Reverse micelles composed of decylmonoacyl glycerol (10MAG) and lauryldimethylamino-N-oxide (LDAO) in low-viscosity alkanes have been shown to preserve the structure and stability of a wide range of biological macromolecules.

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  • Electrical switching of ferroelectric domains enhances piezoelectric activity but typically reduces optical transparency due to light scattering at domain boundaries.
  • Researchers demonstrated that ferroelectric domains in specific perovskite crystals can be manipulated to convert an opaque structure into a transparent one with low electric fields, maintaining strong piezoelectric properties.
  • This dual control over optical and piezoelectric characteristics opens up opportunities for developing advanced photonic devices.
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  • - This study explores the combination of silk protein's properties, like biocompatibility and flexibility, with three types of magnetic nanoparticles to assess their structure and potential uses in sustainability and biomaterials.
  • - Infrared spectroscopy revealed that certain magnetic nanoparticles (magnetite and barium hexaferrite) inhibit the formation of β-sheet structures in silk protein due to strong bonding with its components, while cobalt has minimal impact.
  • - The magnetic composites showed high magnetization and stability even after high-temperature degradation, suggesting promising applications in medical fields such as MRI imaging, tissue regeneration, and drug delivery.
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Growing ultrathin nanogranular (NG) metallic films with continuously varying thickness is of great interest for studying regions of criticality and scaling behaviors in the vicinity of quantum phase transitions. In the present work, an ultrathin gold plasmonic NG film was grown on a sapphire substrate by RF magnetron sputtering with an intentional deposition gradient to create a linearly variable thickness ranging from 5 to 13 nm. The aim is to accurately study the electronic phase transition from the quantum tunneling regime to the metallic conduction one.

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The combination of protein and polysaccharides with magnetic materials has been implemented in biomedical applications for decades. Proteins such as silk, collagen, and elastin and polysaccharides such as chitosan, cellulose, and alginate have been heavily used in composite biomaterials. The wide diversity in the structure of the materials including their primary monomer/amino acid sequences allow for tunable properties.

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  • Flexible and water-insoluble regenerated silk materials show promise for various medical applications due to their unique mechanical properties.
  • * In this study, five types of silk films were created using a specific method (formic acid-calcium chloride) and analyzed using various techniques to compare their physical properties.
  • * Results indicated that the silk films exhibit different structural features compared to natural silk fibers, suggesting that intramolecular β-sheet structures contribute to their water insolubility and flexibility, paving the way for advancements in silk-based biomaterials.
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  • * The increasing demand for biocompatible materials with varying thermal conductivity aligns with advancements in flexible materials and bioelectronics technologies.
  • * This review examines the structure of fibrous proteins (like silk, collagen, and keratin) and discusses how their nano-scale structures impact thermal conductivity, along with methods for measuring their heat transfer properties.
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  • The study presents several new complexes and coordination polymers derived from 15-metallacrown-5 structures that incorporate lanthanide (Ln) and copper (Cu) ions with glycinehydroxamate (GlyHA) and m-phthalate (m-bdc) ligands.
  • Compounds 1 and 3 feature unique quadruple-decker metallacrown assemblies, while compounds 2 and 4 form one-dimensional coordination polymers with solvent-filled crystal lattices.
  • The absorption studies reveal that desolvated compound 4 can uptake methanol and ethanol vapors, and the analysis of magnetic properties shows significant exchange interactions between the metal ions in these complexes.
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  • The study focuses on creating and analyzing silver oxide films (AgO and Ag₂O) intended to be used as antibacterial coatings to prevent bacterial growth.
  • The coatings are effective against various bacterial strains, showing the ability to kill bacteria and inhibit growth both on solid media and in liquid culture.
  • The release of silver ions from these coatings is influenced by the complexity of the surrounding media, demonstrating strong antibacterial properties while having minimal short-term toxic effects on mammalian cells.
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In ferroelectrics, manifestation of a strong electromechanical coupling is attributed to both engineered domain morphology and phase transformations. However, realization of large sustainable and reversible strains and polarization rotation has been limited by fatigue, nonlinearity and hysteresis losses. Here, we demonstrate that large strain and polarization rotation can be generated for over 40 × 10(6) cycles with little fatigue by realization of a reversible ferroelectric-ferroelectric phase transition in [011] cut Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) relaxor ferroelectric single crystal.

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  • Multiferroic heterostructures are created using Pb(Zr0·52Ti0·48)O3 and Fe0.7Ga0.3 thin films on Si cantilevers, allowing for advanced integration.
  • These structures operate in a non-linear regime, enhancing the coupling between mechanical and magnetic/electric properties.
  • Bistable dynamic states are developed that can be switched back and forth using DC magnetic and electric fields, enabling tunability of the resonant frequency.
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  • Magnetoelectric oxide heterostructures are targeted for use in spintronic memory and logic devices, which use spin transport to convey information.
  • The study presents local measurements showing how strain and charge affect magnetization in a specific material system (La0.7Sr0.3MnO3/PbZr0.2Ti0.8O3) using advanced spatial characterization techniques.
  • The findings indicate that local structural changes and charge screening alter magnetization, which can be fine-tuned by adjusting the thickness of the material layers, impacting future device technologies.
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Chemical and structural heterogeneity and the resulting interaction of coexisting phases can lead to extraordinary behaviours in oxides, as observed in piezoelectric materials at morphotropic phase boundaries and relaxor ferroelectrics. However, such phenomena are rare in metallic alloys. Here we show that, by tuning the presence of structural heterogeneity in textured Co(1-x)Fe(x) thin films, effective magnetostriction λ(eff) as large as 260 p.

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  • - Hybrid nanobeads featuring manganese-oxo or manganese-iron-oxo clusters were successfully created using the miniemulsion polymerization method.
  • - New metal-oxo clusters, Mn(12)O(12)(VBA)(16)(H(2)O)(4) and Mn(8)Fe(4)O(12)(VBA)(16)(H(2)O)(4), were synthesized and characterized, introducing a functional group (4-vinylbenzoate or VBA) into the clusters.
  • - The resulting polymer nanoparticles, formed from these clusters and styrene, were uniform in size and measured around 60 nm in diameter, with comprehensive analysis conducted on their properties and structure.
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Synthesis of uniform silica shell over Co3O4 nanoparticles was carried out using the colloidal solutions of Tergitol and cyclohexane. The shell could be controlled to a thickness of up to 20 nm by varying different parameters such as the amount of tetraethylorthosilicate, concentration of Co3O4 nanoparticles, reaction time and the presence of water and 1-octanol. Control of the amount of water (required for hydrolysis) appears to be the key factor for controlling the shell thickness.

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  • * The synthesis process involves adjusting the niobium precursor to boron ratio and reaction conditions to produce various nanostructures, including core-shell structures, and was characterized using techniques like XRD, HRTEM, and EDX.
  • * Niobium diboride nanorods exhibit superconductivity with a critical transition temperature of 6.4 K, but this superconductivity is hidden in the core-shell structure
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  • Researchers created nickel borate nanostructures with specific sizes and shapes using a method involving a precursor made in microemulsions with Tergitol as a surfactant.
  • By experimenting with different co-surfactants like 1-butanol, 1-hexanol, and 1-octanol, they produced uniform nanorods and nanospindles of varying dimensions.
  • The resulting nanorods exhibited antiferromagnetic properties, with a Néel temperature between 44 to 47 K, and showed an increase in magnetic moment as the rods became thinner.
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Four new 5-aminoisophthalates of cobalt and nickel have been prepared employing hydro/solvothermal methods: [Co(2)(C(8)H(5)NO(4))(2)(C(4)H(4)N(2))(H(2)O)(2)].3H(2)O (I), [Ni(2)(C(8)H(5)NO(4))(2)(C(4)H(4)N(2))(H(2)O)(2)].3H(2)O (II), [Co(2)(H(2)O)(mu(3)-OH)(2)(C(8)H(5)NO(4))] (III), and [Ni(2)(H(2)O)(mu(3)-OH)(2)(C(8)H(5)NO(4))] (IV).

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Anisotropic growth of magnetite (Fe3O4) nanoparticles is achieved in a hydrothermal growth process using hexamine to play a dual role of oxide forming and directing agent. The samples are characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, squid magnetometry, ferromagnetic resonance technique, diffuse reflectance spectroscopy and Mössbauer spectroscopy, which collectively establish the formation of Fe3O4 phase. Anisotropic structures such as nanorods and nanotubules are revealed and these are shown to exhibit good humidity sensing properties.

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  • Appropriate microemulsion systems were used to produce hexagonal cobalt and cobalt-nickel alloy nanoparticles with cetyltrimethylammonium bromide as a surfactant at high temperatures, achieving stabilization of hexagonal cobalt at very small sizes.
  • Annealing hcp cobalt nanoparticles in hydrogen at 700 degrees Celsius transformed them into fcc cobalt nanoparticles, with microscopy revealing spherical nanoparticles in different sizes and structures.
  • Electrochemical tests indicated that cobalt nanoparticles outperform cobalt-nickel alloy nanoparticles at voltages below 0.65 V, whereas the alloy shows better efficiency at higher voltages, and all nanoparticles display ferromagnetism, though saturation magnetization is reduced due to potential surface oxidation.
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  • * This stabilization made it possible to study how well the cluster could be used as a contrast agent for MRI scans.
  • * The research focused on the potential benefits of using Mn-12 in medical imaging.
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Rod-shaped nanostructures of cobalt oxalate dihydrate were synthesized at room temperature by the microemulsion (reverse micellar) route. These rods are highly uniform in length and can be modified with temperature (from approximately 6.5 microm at 50 degrees C to approximately 2.

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