Decades in the Making: The Evolution of Digital Health Research Infrastructure Through Synthetic Data, Common Data Models, and Federated Learning.

Traditionally, medical research is based on randomized controlled trials (RCTs) for interventions such as drugs and operative procedures. However, increasingly, there is a need for health research to evolve. RCTs are expensive to run, are generally formulated with a single research question in mind, and analyze a limited dataset for a restricted period.

Nonlinear Optical Properties of Discotic Hexylthiotruxene Derivatives.

The search for efficient and transparent nonlinear optical (NLO) media has led to the investigation and development of alternative organic optical materials. In this context, a series of new hexylthiotruxene derivatives have been synthesized, and their linear and NLO properties are explored. These truxene derivatives show large NLO absorption due to their C symmetry, presence of large hyperpolarizability, and extended π-conjugation.

Acousto-optic modulator-based improvement in imaging through scattering media.

Reduced visibility is a common problem when light traverses through a scattering medium, and it becomes difficult to identify an object in such scenarios. What we believe to be a novel proof-of-principle technique for improving image visibility based on the quadrature lock-in discrimination algorithm in which the demodulation is performed using an acousto-optic modulator is presented here. A significant improvement in image visibility is achieved using a series of frames.

Synthesis, crystal structure and Hirshfeld surface analysis of the ortho-rhom-bic polymorph of 4-bromo--(4-bromo-benzyl-idene)aniline.

The crystal structure of the title compound, CHBrN [systematic name: ()-,1-bis-(4-bromo-phen-yl)methanimine], is a second polymorph (Form II) crystallizing in the ortho-rhom-bic space group . The first polymorph (Form I) crystallizes in the monoclinic space group 2/ [Bernstein & Izak (1975 ▸). , 257-266; Marin (2013 ▸).

Two Photon Absorption Properties of CBHB and DEABHB Single Crystals for Optical Limiting Applications.

Novel materials of (E)-N'-(4-chlorobenzylidene)-4-hydroxybenzohydrazide (CBHB) and (E)-N'-(4-(diethylamino) benzylidene)-4-hydroxybenzohydrazide (DEABHB) were synthesized by condensation reaction process and solvent evaporation method was employed to grow CBHB and DEABHB single crystals at room temperature. Lattice parameters of CBHB and DEABHB compounds were recorded using single crystal X-ray diffraction method. The presence of functional groups of the synthesized CBHB and DEABHB compounds were confirmed by Fourier transform infrared and Fourier transform Raman spectral analyses.

Fluorescence and Nonlinear Optical Response of Graphene Quantum Dots Produced by Pulsed Laser Irradiation in Toluene.

Graphene quantum dots (GQDs), the zero dimensional (0D) single nanostructures, have many exciting technological applications in diversified fields such as sensors, light emitting devices, bio imaging probes, solar cells, etc. They are emerging as a functional tool to modulate light by means of molecular engineering due to its merits, including relatively low extend of loss, large outstretch of spatial confinement and control via doping, size and shape. In this article, we present a one pot, facile and ecofriendly synthesis approach for fabricating GQDs via pulsed laser irradiation of an organic solvent (toluene) without any catalyst.

Fabrication of Silver-Decorated Graphene Oxide Nanohybrids via Pulsed Laser Ablation with Excellent Antimicrobial and Optical Limiting Performance.

The demand for metallic nanoparticle ornamented nanohybrid materials of graphene oxide (GO) finds copious recognition by virtue of its advanced high-tech applications. Far apart from the long-established synthesis protocols, a novel laser-induced generation of silver nanoparticles (Ag NPs) that are anchored onto the GO layers by a single-step green method named pulsed laser ablation has been exemplified in this work. The second and third harmonic wavelengths (532 nm and 355 nm) of an Nd:YAG pulsed laser is used for the production of Ag NPs from a bulk solid silver target ablated in an aqueous solution of GO to fabricate colloidal Ag-GO nanohybrid materials.

Mechanistic insights into the optical limiting performance of carbonaceous nanomaterials embedded with core-shell type graphite encapsulated Co nanoparticles.

Globular amorphous carbonaceous materials embedded with graphite encapsulated metallic Co-nanoparticles with a high degree of crystallinity are synthesized by pyrolysis and demonstrated as excellent candidates for optical limiters. The amount of metal precursor (Co-acetylacetonate) used with toluene for pyrolysis is chosen as a strategy to control the degree of graphitization of graphene-like shells around the embedded Co-nanoparticles and also the crystallinity of these Co nanoparticles in the samples. The graphitic shell with an optimum amount of defects tunes the electronic properties of these nanomaterials, providing the electronic states required for the enhancement of nonlinear optical absorption (NLA) through an excited state absorption (ESA) process.

Observation of ion acceleration in nanosecond laser generated plasma on a nickel thin film under rear ablation geometry.

In this article we report acceleration observed for the ions produced in a 50-nm-thick nickel film coated on a quartz substrate, under nanosecond laser ablation, in the rear ablation geometry. A detailed study with varying background pressure and laser energy is done. Spectroscopic study including spectroscopic time of flight (STOF) measurements of ionic and other neutral transitions from the plasma has been undertaken.

Whole-mol-ecule disorder of the Schiff base compound 4-chloro--(4-nitro-benzyl-idene)aniline: crystal structure and Hirshfeld surface analysis.

In the crystal of the title Schiff base compound, CHClNO, [CNBA; systematic name: ()--(4-chloro-phen-yl)-1-(4-nitro-phen-yl)methanimine], the CNBA mol-ecule shows whole-mol-ecule disorder (occupancy ratio 0.65:0.35), with the disorder components related by a twofold rotation about the shorter axis of the mol-ecule.

Molecular structure, NLO properties and vibrational analysis of l-Histidine tetra fluro borate by experimental and computational spectroscopic techniques.

l-histidine tetra fluroborate (L-HTFB) is a semi-organic NLO material. Ab-initio computations were performed at CAM-B3LYP/ 6-311++g(d,p) level of theory to arrive at the structures, energies, and vibrational wave numbers. The experimental FT-IR and FT-Raman spectra of L-HTFB have been recorded and analyzed.

Effect of Mannitol on Intraocular Pressure in Vitrectomized and Nonvitrectomized Eyes: A Prospective Comparative Study.

Purpose: To compare the effect of mannitol in reducing intraocular pressure (IOP) in vitrectomized and nonvitrectomized eyes.

Materials And Methods: Prospective comparative case study. Eyes with IOP≥40 mm Hg were included.

Intermediate-term outcome of Aurolab aqueous drainage implant.

Purpose: To report the intermediate-term safety and efficacy of Aurolab aqueous drainage implant (AADI) in patients with glaucoma.

Methods: Retrospective review of patients who underwent AADI between January 2013 and December 2016. Patients aged >16 years and with a minimum follow-up of 6 months were included.

Enhanced Ultrafast Nonlinear Optical Response in Ferrite Core/Shell Nanostructures with Excellent Optical Limiting Performance.

Nonlinear optical nanostructured materials are gaining increased interest as optical limiters for various applications, although many of them suffer from reduced efficiencies at high-light fluences due to photoinduced deterioration. The nonlinear optical properties of ferrite core/shell nanoparticles showing their robustness for ultrafast optical limiting applications are reported. At 100 fs ultrashort laser pulses the effective two-photon absorption (2PA) coefficient shows a nonmonotonic dependence on the shell thickness, with a maximum value obtained for thin shells.

Optical nonlinearity and charge transfer analysis of pyrene adsorbed on silver: Computational and experimental investigations.

The interaction of pyrene on silver has been investigated using both experimental and computational methods. Hyperpolarizabilities computed theoretically together with experimental nonlinear absorption from open aperture Z-scan measurements, point towards a possible use of pyrene adsorbed on silver in the rational design of NLO devices. Presence of a red shift in both simulated and experimental UV-Vis spectra confirms the adsorption on silver, which is due to the electrostatic interaction between silver and pyrene, inducing variations in the structural parameters of pyrene.

Syntheses, Spectroscopic, Electrochemical, and Third-Order Nonlinear Optical Studies of a Hybrid Tris{ruthenium(alkynyl)/(2-phenylpyridine)}iridium Complex.

The synthesis of fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡CH)}3] (10), which bears pendant ethynyl groups, and its reaction with [RuCl(dppe)2]PF6 to afford the heterobimetallic complex fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡C-trans-[RuCl(dppe)2])}3] (11) is described. Complex 10 is available from the two-step formation of iodo-functionalized fac-tris[2-(4-iodophenyl)pyridine]iridium(III) (6), followed by ligand-centered palladium-catalyzed coupling and desilylation reactions. Structural studies of tetrakis[2-(4-iodophenyl)pyridine-N,C1′](μ-dichloro)diiridium 5, 6, fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CH)}3] (8), and 10 confirm ligand-centered derivatization of the tris(2-phenylpyridine)iridium unit.

Ensemble effect of intrinsic defects and Mn ions on the enhancement of third order nonlinearity of ZnO nanoparticles.

Mn doped ZnO nanoparticles were synthesized by the chemical co-precipitation method and XRD confirms the hexagonal structure of nanoparticles with good crystallinity. From TEM analysis, the average crystallite size of the nanoparticles is evaluated as 7-13 nm. All the prepared nanoparticles exhibit reverse saturable absorption in open aperture Z-scan measurements.

Defect engineering in ZnO nanocones for visible photoconductivity and nonlinear absorption.

Nanostructured ZnO is a promising material for optoelectronic and nonlinear optical applications because of the flexibility of band gap engineering by means of various defect states present in it. Employing the time-correlated single photon counting photoluminescence technique, the correlation between defect levels and optoelectronic and nonlinear optical properties of ZnO is explored in this work. By a facile solution method, ZnO nanocones with a dominating preferential orientation along energetically less favorable, oxygen terminated (10̄11) facets were synthesized using a passivating capping agent.

The role of defects in the nonlinear optical absorption behavior of carbon and ZnO nanostructures.

In bulk materials, defects are usually considered to be unwanted since deviations from perfect lattices may degrade device performance. Interestingly, the presence of defects throws open new possibilities in the case of nanostructures due to the properties related to their limited size scale. Defects and disorders which alter the electronic structure of nanostructures can significantly influence their electronic, magnetic and nonlinear optical properties.

Synthesis and spectroscopic characterization of copper zinc aluminum nanoferrite particles.

Copper doped zinc aluminum ferrites CuxZn1-x.(AlxFe2-x)O4 are synthesized by the solid-state reaction route and characterized by XRD, TEM, EPR and non linear optical spectroscopy techniques. The average particle size is found to be from 35 to 90nm and the unit cell parameter "a" is calculated as from 8.

Enhanced optical limiting in polystyrene-ZnO nanotop composite films.

In this work we investigate the optical limiting property of polystyrene-zinc-oxide (ZnO) nanotop composite films, using an open aperture Z-scan technique. The nanocomposites are prepared for different loading concentrations of ZnO and are fabricated using spin and dip coating techniques. On exposing the films to a pulsed nanosecond laser at 532 nm, the nonlinear absorption (NLA) coefficient is found to be greater for spin-coated films compared to dip-coated films.

Optical diode action from axially asymmetric nonlinearity in an all-carbon solid-state device.

Nanostructured carbons are posited to offer an alternative to silicon and lead to further miniaturization of photonic and electronic devices. Here, we report the experimental realization of the first all-carbon solid-state optical diode that is based on axially asymmetric nonlinear absorption in a thin saturable absorber (graphene) and a thin reverse saturable absorber (C60) arranged in tandem. This all-optical diode action is polarization independent and has no phase-matching constraints.

Nonlinear optical properties of boron doped single-walled carbon nanotubes.

Single-walled carbon nanotubes (SWCNTs) exhibit excellent nonlinear optical (NLO) properties due to the delocalized π electron states present along their tube axis. Using the open aperture Z-scan method in tandem with X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, we demonstrate the simultaneous tailoring of both electronic and NLO properties of SWCNTs, from ultrafast (femtosecond) to relatively slow (nanosecond) timescales, by doping with a single substituent, viz., boron.

Ultrafast optical nonlinearity, electronic absorption, vibrational spectra and solvent effect studies of ninhydrin.

FT-IR, FT-Raman and UV-Vis spectra of the nonlinear optical molecule ninhydrin have been recorded and analyzed. The equilibrium geometry, bonding features, and harmonic vibrational wavenumbers have been investigated with the help of B3LYP density functional theory method. A detailed interpretation of the vibrational spectra is carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology.

Multi-photon absorption effect and intra-molecular charge transfer of donor-π-acceptor chromophore ethyl p-amino benzoate.

Fourier transform (FT)-Raman and infrared (IR) spectra of the nonlinear optical (NLO) material ethyl p-amino benzoate (EPAB) have been recorded and analyzed. The geometry and harmonic vibrational wavenumbers are calculated with the help of B3LYP density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology.