Comparative study of evaluating the microcirculatory function status of primary small HCC between the CE (DCE-MRI) and Non-CE (IVIM-DWI) MR Perfusion Imaging.

PURPOSE: To compare the difference of evaluating the microcirculatory function status of primary small HCC between DCE-MRI with two-compartmental pharmacokinetic model and IVIM-DWI. METHODS: 27 patients (22 men, 5 women; mean age, 49 years; range 36-65 years) with primary single sHCC who underwent IVIM-DWI and DCE-MRI before the operation were included in this retrospective study. The MR perfusion parameters are Ktrans, Ve, Kep, D, D* and f. Pathological results include pathological grade (low grade ≤ II, high grade > II) and MVD. The perfusion parameters and pathological results of sHCC were analyzed and compared in their relevance, sensitivity and specificity. Statistical methods included Spearman and ROC curve analysis. RESULTS: The perfusion parameters (Ktrans, Kep, D*, f) were significantly positive correlated (r = 0.892, 0.808, 0.589 and 0.543, P = 0.000, 0.000, 0.001 and 0.003 with MVD of sHCC. The parameter Ve and D values were negatively correlated (r = - 0.454 and - 0.399, P = 0.017 and 0.039, respectively) with the pathological grade. Regarding the evaluation MVD of sHCC, the evaluation of the sensitivity and specificity performance was present in descending order: Ktrans > Kep > PF > D*. In the evaluation pathological grade of sHCC, the sensitivity and specificity were better by parameters D than Ve. CONCLUSION: DCE-MRI is better than IVIM-DWI for evaluation microcirculation functional status of sHCC. But for evaluating the pathological grade, IVIM-DWI is better than DCE-MRI. Combination of the two imaging techniques may provide more comprehensive evaluation in microcirculation functional status of the sHCC.

Transition from discrete patches to plasmonic nanohole array by glancing angle deposition on nanosphere monolayers.

By combining nanosphere lithography and glancing angle deposition, a morphological transition from disconnected patchy silver (Ag) coated nanosphere particles to a connected Ag nanohole sheet on close-packed nanosphere monolayers has been demonstrated, which significantly changes the optical property of the Ag nanostructure deposited. For different sized nanosphere monolayers, when the vapor incident angle was set to be 55°, the transmission spectra showed complicated features when the Ag deposition thickness was less than 60 nm. When the thickness was large enough (≥60 nm), a distinguished extraordinary optical transmission (EOT) peak was observed. The EOT peak wavelength position is independent of the Ag thickness deposited and is proportional to the nanosphere diameter. The obtained EOT peaks possess a high quality factor and have high transmission values compared to those reported in the literature for similar structures. The Monte Carlo growth simulations demonstrate the morphological transition from the patchy arrays to nanohole arrays while the electromagnetic numerical calculations confirm the change in the optical properties. Such a high quality EOT response could be used for constructing better sensors or developing other plasmonic applications.

Facet-mediated growth of silver nanoparticles on biaxial calcium fluoride nanorod arrays.

The surface orientation of metal nanoparticles is critical to their physical and chemical properties. This study aims on the understanding of the effect of surface orientation as well as heterogeneous epitaxy of metal nanoparticles at an interface between two materials with a large lattice mismatch. Silver nanoparticles of different diameters were grown on arrays of calcium fluoride (CaF2) nanorods using oblique angle deposition as a model system for this study. Scanning electron microscopy and transmission electron microscopy (TEM) imaging were used to verify that the nanoparticles were selectively grown on the desired {111} facets of the nanorod tips. Using selected area diffraction and dark field imaging in TEM, it was shown that the nanoparticles were grown at a (111) orientation at the CaF2 interface with large lattice strains. Thus biaxially textured CaF2 nanorod arrays can be used as a catalytic support.

Tuning the plasmonic properties of silver nanopatterns fabricated by shadow nanosphere lithography.

Regular silver (Ag) nanopatterns, from disconnected nanotriangles to well coupled triangular clusters of nanoparticles, were prepared by shadow nanosphere lithography at different incident angles θ from 0° to 20° with continuous azimuthal rotation. The resulting nanopatterns were consistent with predictions by numerical calculations and Monte Carlo simulations of adatoms with high diffusivity. The visible localized surface plasmon resonance of these nanopatterns was tuned by θ systematically due to the change in size, shape, and arrangement of Ag nanopatterns. These resonances were consistent with finite-difference time-domain simulations using realistic nanopatterns based upon scanning electron micrographs. Such a simple fabrication strategy can be used to optimize surface enhanced Raman scattering substrate fabrication, as well as other plasmonics based applications.

Discovery of 5-(4-hydroxyphenyl)-3-oxo-pentanoic acid [2-(5-methoxy-1H-indol-3-yl)-ethyl]-amide as a neuroprotectant for Alzheimer's disease by hybridization of curcumin and melatonin.

In our effort to develop effective neuroprotectants as potential treatments for Alzheimer's disease (AD), hybrid compounds of curcumin and melatonin, two natural products that have been extensively studied in various AD models, were designed, synthesized, and biologically characterized. A lead hybrid compound (7) was discovered to show significant neuroprotection with nanomolar potency (EC50 = 27.60 ± 9.4 nM) in MC65 cells, a cellular AD model. Multiple in vitro assay results established that 7 exhibited moderate inhibitory effects on the production of amyloid-ß oligomers (AßOs) in MC65 cells, but not on the aggregation of Aß species. It also exhibited significant antioxidative properties. Further mechanistic studies demonstrated that 7's antioxidant effects correlate well with its neuroprotective potency for MC65 cells, and these effects might be due to its interference with the interactions of AßOs within the mitochondria of MC65 cells. Furthermore, 7 was confirmed to cross the blood-brain barrier (BBB) and deliver a sufficient amount to brain tissue after oral administration. Collectively, these results strongly support the hybridization approach as an efficient strategy to help identify novel scaffolds with a desired pharmacology, and strongly encourage further optimization of 7 to develop more potent neuroprotectants for AD.

Highly sensitive detection of blood by surface enhanced Raman scattering.

Raman spectroscopy for forensic body fluid analysis has received some attention due to the nondestructive nature and potential application for identification at the crime scene; however, its usage has been limited by low detection sensitivity. Surface enhanced Raman scattering (SERS) was evaluated for blood identification for forensic applications. Specifically, a SERS-active substrate was fabricated, composed of nickel nanotips coated with Ag nanoparticles. Compared with a conventional substrate, the SERS substrate enhanced Raman scattering by more than two orders of magnitude and allowed blood to be identified to a dilution of 1:100,000. Blood was also successfully detected by swabbing the SERS substrate directly on mock evidence. Most importantly, Raman spectra obtained by swabbing the SERS substrate on blood stains were free of luminescence even when blood was deposited on luminescent fabrics. The nondestructive character, simplicity of sample preparation, and high sensitivity make SERS a prime candidate for field and laboratory-based blood identification.

Highly efficient electron field emission from graphene oxide sheets supported by nickel nanotip arrays.

Electron field emission is a quantum tunneling phenomenon whereby electrons are emitted from a solid surface due to a strong electric field. Graphene and its derivatives are expected to be efficient field emitters due to their unique geometry and electrical properties. So far, electron field emission has only been achieved from the edges of graphene and graphene oxide sheets. We have supported graphene oxide sheets on nickel nanotip arrays to produce a high density of sharp protrusions within the sheets and then applied electric fields perpendicular to the sheets. Highly efficient and stable field emission with low turn-on fields was observed for these graphene oxide sheets, because the protrusions appear to locally enhance the electric field and dramatically increase field emission. Our simple and robust approach provides prospects for the development of practical electron sources and advanced devices based on graphene and graphene oxide field emitters.

Very low-refractive-index optical thin films consisting of an array of SiO2 nanorods.

The refractive-index contrast in dielectric multilayer structures, optical resonators, and photonic crystals is an important figure of merit that creates a strong demand for high-quality thin films with a low refractive index. A SiO2 nanorod layer with low refractive index of n = 1.08, to our knowledge the lowest ever reported in thin-film materials, is grown by oblique-angle electron-beam deposition of SiO2. A single-pair distributed Bragg reflector employing a SiO2 nanorod layer is demonstrated to have enhanced reflectivity, showing the great potential of low-refractive-index films for applications in photonic structures and devices.