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Screening of two-photon activated photodynamic therapy sensitizers using a 3D osteosarcoma model
摘要： Photodynamic therapy (PDT) involves a photosensitizing agent activated with light to induce cell death. Two-photon excited PDT (TPE-PDT) offers numerous benefits compared to traditional one-photon induced PDT, including an increased penetration depth and precision. However, the in vitro profiling and comparison of two-photon photosensitizers (PS) are still troublesome. Herein, we report the development of an in vitro screening platform of TPE-PS using a 3D osteosarcoma cell culture. The platform was tested using three different two-photon (2P) active compounds – a 2P sensitizer P2CK, a fluorescent dye Eosin Y, and a porphyrin derivative (TPP). Their 2P absorption cross-sections (σ2PA) were characterised using a fully automated z-scan setup. TPP exhibited a remarkably high σ2PA at 720 nm (8865 GM) and P2CK presented a high absorption at 850 nm (405 GM), while Eosin Y had the lowest 2P absorption at the studied wavelengths (<100 GM). The cellular uptake of PS visualized using confocal laser scanning microscopy showed that both TPP and P2CK were internalized by the cells, while Eosin Y stayed mainly in the surrounding media. The efficiency of the former two TPE-PS was quantified using the PrestoBlue metabolic assay, showing a significant reduction in cell viability after two-photon irradiation. The possibility of damage localization was demonstrated using a co-culture of adipose derived stem cells together with osteosarcoma spheroids showing no signs of damage to the surrounding healthy cells after TPE-PDT.
关键词： two-photon excited photodynamic therapy,PrestoBlue assay,photosensitizers,cellular uptake,localized damage,z-scan,3D osteosarcoma model
更新于2025-11-21 11:08:12
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Cu nanoclusters in ion exchanged soda-lime glass: Study of SPR and nonlinear optical behavior for photonics
摘要： Nanomaterials with large optical nonlinearities have received considerable attention in the field of modern science and nanotechnology. In this paper, we have studied nonlinear optical and surface plasmon resonance properties and behavior of Cu nanoclusters formed in ion exchanged soda-lime glass. The soda-lime glasses were successfully doped with Cu nanoclusters in the ion-exchange process. The size of the clusters estimated from the optical absorption spectroscopy results closely matched with those obtained from the transmission electron microscopy data. The results revealed that spherical shaped Cu nanoclusters were homogeneously distributed in the glass matrix and the size of the Cu nanoclusters varied from 4 to 10 nm. The structure and chemical state were further analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. The nonlinear optical behavior of the materials was analyzed using femtosecond Z-scan technique. The nonlinear refraction index (n2), nonlinear absorption coefficient (β) and the third-order nonlinear optical susceptibility (χ(3)) were estimated to be -1.72 × 10?17 m2/W, 9.96 × 10?11 m/W, and 0.56 × 10?11 esu, respectively, which shows possible application in the field of photonics.
关键词： Surface plasmon resonance,Z-scan technique,Metal forming and shaping,Structural,Nanoparticles
更新于2025-11-20 15:33:11
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dz2 Orbitals Mediated Bound Magnetic Polarons in Ferromagnetic Ce Doped BaTiO3 Nanoparticles and its Enriched Two Photon Absorption Cross Section
摘要： Enriched ferromagnetism and two photon absorption (TPA) cross section of perovskite BaTiO3 nanoparticles are indispensible for magnetic and optical data storage applications. In this work, the hydrothermally synthesized Ce doped BaTiO3 nanoparticles exhibit the maximum room temperature ferromagnetism (4.26×10-3 emu/g) at 4 mol% due to the increase of oxygen vacancies as evidenced by X-ray photoelectron, electron spin resonance spectroscopies and density functional theory (DFT) calculations. Hence, the oxygen vacancy constituted bound magnetic polaron (BMP) model has been invoked to explain the enhancement of ferromagnetism. BMP theoretical model indicates the increase of BMP magnetization (M0, 3.0 to 4.8×10-3 emu/g) and true spontaneous moment per BMP (meff, 4 to 9.88×10-4 emu) on Ce doping. DFT calculations show that BMPs mediate via Ti d orbitals leading to the ferromagnetism. Besides, it is understood that the magnetic moment induced by Ce at Ba site is higher than Ce at Ti site in the presence of oxygen vacancies. Open aperture Z-scan technique displays the highest TPA coefficient β (7.08×10-10 m/W) and TPA cross section σTPA (455×104 GM) at 4 mol% of Ce as a result of robust TPA induced excited state absorption. A large σTPA is attributed to the longer excited state lifetime τ (7.63 ns) of charge carriers created by oxygen vacancies and Ce ions which encounter several electronic transitions in the excited sub-states.
关键词： Ce doping,oxygen vacancies,bound magnetic polarons,two photon absorption,DFT calculations,Z-scan technique,BaTiO3 nanoparticles,ferromagnetism
更新于2025-11-19 16:56:35
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Facile synthesis of extended TPA-quinazolinone derivatives and the nonlinear optical properties
摘要： In this work, four new quinazolinone(QZ)-based compounds containing triphenylamine (TPA) moiety have been synthesized, defined as QZC, QZC-1, QZC-2, QZC-3, for the application of third-order nonlinear optical (NLO) responses. A new design of two-step synthesis has been put forward, the first step is Ullmann reaction with QZ, and the second is connecting QZ and the substituted triphenylamines (TPAs) through a Suzuki cross-coupling reaction to afford the target products. Electrochemical measurement data indicated that the tuning of the HOMO and LUMO energy levels can be easily achieved by introducing and modifying the donor moiety. The NLO properties were evaluated by the Z-scan technique which showed that introduction of a benzene ring as a π bridge could reduce the transmission energy of electrons from a ground state to an excited state, and the added methoxy in TPA moiety could promote the ICT, and improve the third-order NLO properties of molecules. Theoretical calculations matched well with the electrochemical information and NLO information. The results suggest that the materials based on QZ have potential applications in integrated NLO devices.
关键词： Fluorescence,photophysical property,Extended Quinazolinone derivative,third-order NLO material,Z-scan technology
更新于2025-11-19 16:46:39
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Third Order Nonlinear Properties of Pure and Na doped L-Arginine Acetate Single Crystal by Z-scan Technique
摘要： Single crystals of pure and Na doped L-arginine acetate (LAA) has been successfully grown from aqueous solution by slow evaporation technique. The crystalline qualities of the grown crystals were confirmed by powder X-ray diffraction studies. The nonlinear refractive index n2 and nonlinear susceptibility c(3) have been measured through the Z-scan technique. The results indicate that the compound exhibits reverse saturation absorption and self defocusing performance. Non-linear absorption co-efficient (b), the non-linear refractive index (n2), the real and imaginary parts of non-linear susceptibility c (3) have been measured at 632.8 nm.
关键词： Z-scan Technique,Na doped L-arginine acetate (LAA),Crystal
更新于2025-09-23 15:23:52
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Extensive Study of Rhodanine-Arylamine-Based Chromophores: Consolidated Optical, DFT/TD-DFT and Non-Linear Optical Properties
摘要： Three push-pull rhodanine-arylamine based D-π-A dyes (2a-2c) are prepared to study the effect of donor on electronic, linear and nonlinear optical properties. The dyes, 2a,2b and 2c have a vinyl spacer conjugated with triphenylamine, julolidine, and carbazole donors respectively, with a methoxy group and rhodanine-3-acetic acid. The dyes exhibited solvent dependent absorption-emission up to the red region with large Stokes shifts (2a = 77-130 nm). This dyes possess charge transfer characteristics as established by transition dipole moment (μeg), dipole moment ratio (μe/μg), Generalised Mulliken-Hush analysis, and electron distribution (DFT). The non-linear optical study revealed that quadratic hyperpolarizability (μβCT) are 1098.9 (2a), 515.0 (2b) and 339.6 x 10-48 e.s.u. (2c) depending on donor strength. The intrinsic hyperpolarizabilities fall below βint0 = 10-3/2 limit i.e. less than unity. Solvatochromic two-level model is used to study the trends in two photon cross-section (σ2PA). The dye 2a exhibited high σ2PA, 216 GM (λmax 485 nm and 564 nm). The dyes 2a and 2c with analogue dye 3a show reverse saturable absorption (RSA) therefore, show positive third order nonlinear absorption coefficient, β and reasonable values of third order nonlinear susceptibility and high laser damage threshold. The Re χ(3) factors are responsible for the high values of χ(3) in the range of 0.77 to 8.09 x 10-12 e.s.u. Therefore, this material would serve as good candidate in the photonic application.
关键词： hyperpolarizability,Z scan,Arylamine donors,σ2PA,LDT
更新于2025-09-23 15:23:52
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Improved femtosecond third-order nonlinear optical properties of thin layered Cu3Nb2O8
摘要： Thin motif-layered triclinic Cu3Nb2O8 was prepared through solid-state reaction at 700 °C, 12 h and their nonlinear optical (NLO) properties with ultrafast [800 nm, 150 fs (fs) pulses, 80 MHz repetition rate] pulse laser excitation were studied. A peculiar shift from reverse saturable absorption (RSA) to saturable absorption (SA) at a peak intensity of 40 MW/cm2 was observed. The involvement of excited state absorption (ESA) is confirmed from the decrease in the nonlinear absorption coefficient with increase in peak intensity and the observed nonlinearity is ascribed to a sequential 2 PA process (1 PA+ESA). Formation of layered structure in Cu3Nb2O8 acted as a transport layers which yielded high nonlinear absorption coefficient (7.8 × 10^{-10} m/W), nonlinear refractive index (5.17 × 10^{-16} m^2/W) and nonlinear optical susceptibility (25.6 × 10^{-11} esu) when compared to other known copper niobates. The observation of low onset-limiting threshold (78.79–26.26 μJ/cm^2) renders Cu3Nb2O8 a prospective material for ultrashort pulse laser protecting device and biomedical microsurgery tools. A transition of mixed phase CuNb2O6-Cu3Nb2O8 into pure triclinic Cu3Nb2O8 along with change in morphology from pore to layered structure with increase in sintering time was confirmed from powder XRD, Raman, FESEM measurements and UV–Visible absorption studies.
关键词： Femtosecond,Copper niobate,Optical limiting,Z-scan
更新于2025-09-23 15:23:52
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Monodimensional enlargement of resolved field of view in line scan cameras by a single doubly symmetric mirror
摘要： The geometry of the sensed and thus optically relevant area in the image plane of line scan cameras suggests that improvement of the overall system is possible, by joint design of optics and electronics. By a technique named Linear Fovea (LF) proposed in this paper, the optical contrast along the Line-of-Interest (LOI) in the image plane i.e. the location of the opto-electronic sensor, is optimized at the expense of contrast elsewhere. In the LF method, employing a single doubly symmetric surface, the resolved ?eld of view (RFOV) as the merit function, is maximized, by ?nding appropriate Zernike coe?cients describing that surface. The technique is applied on a proof-of-concept single mirror telescope and both MTF analysis and standard target imaging simulation are performed. Results show that by this technique, the RFOV can be doubled, or alternatively the illumination can be increased 2.5 times keeping RFOV unchanged. Furthermore, a rather uniform response is kept along the LOI.
关键词： Foveated imaging,Aberration compensation,Lens design,Wide ?eld angle lenses,Free form optics,Line scan cameras
更新于2025-09-23 15:23:52
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Spectral and third order nonlinear optical properties of Yttrium-doped BaWO4 nanostructures
摘要： BaWO4 nanostructures doped with different concentrations of Yttrium have been synthesized by a chemical method. The as-prepared samples were characterized by UV–vis diffuse reflectance spectra, X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron microscopy and Raman spectra. From the UV–vis spectra, it is seen that absorption band edge shifted towards the visible region upon Y doping. The X-ray diffraction and Raman analyses reveal that the BaWO4 powders present a tetragonal structure. The third-order nonlinear optical responses of BaWO4 nanostructures on the effect of Y concentrations was investigated by Z-scan technique using a continuous wave Nd:YAG laser at 532 nm. Experimental results have shown that the observed nonlinear absorption and nonlinear refraction behavior is attributed to saturable absorption and thermal nonlinear effects.
关键词： Nanostructures,Yttrium,Saturable absorption,Z-scan
更新于2025-09-23 15:23:52
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Design and development of a mobile robotic CT system for intraoperative use
摘要： This paper presents the design of a mobile robotic computed tomography (CT) system for intraoperative use. In particular, this paper presents a novel gantry mechanism and a novel mechanism generating isocentric motions. The developed system mechanically consists of: (1) a gantry and (2) a mobile robotic body. The gantry contains the X-ray modules and has an opening mechanism that enables full 360 degree rotation. The robotic body is capable of one vertical and two isocentric rotational motions used to position the gantry. Unlike existing C-arms and mobile CT scanners, each isocentric motion is achieved using a single-DOF mechanism. With these robotic motions, the mobile robotic CT system can be used intraoperatively in both CT and fluoroscopic imaging modes. The mobile platform enables installation and removal of the device from a surgical bed. The performance of the proposed system was investigated using a laser tracking system. Experimental results show that no significant vibrations or position deviations of the X-ray modules were observed during CT scanning motion.
关键词： Isocentric motion,Robotic CT,Full-Scan,CT,X-ray,Opening Gantry
更新于2025-09-23 15:22:29