RESUMO
BACKGROUND: recently much studies evidenced the potential role of photo-biomodulation (PBM) in patients affected by Age-related Macular Degeneration (AMD). We designed a new wearable device for self-medication that employs the same broadband red light described in literature, but with extremely low irradiance. AIM: to demonstrate the safety and effectiveness of low-fluence light stimulations emitted by a LED source with appropriate wavelengths through our new device in improving short-term visual function in patients affected by severe non neovascular AMD. MATERIALS AND METHODS: we prospectively enrolled patients affected by severe non-neovascular AMD with a relative sparing of the foveal region. All the patients were randomly assigned in placebo or in treatment group. The treatment consisted of 10 sessions of 10-min each, using the new device comprised of micro-LEDs that emitted light onto an amorphous support assembled within Metallic eyeglasses. The placebo group blindly underwent the same number of PBM sessions with the micro-LED turned off. Before and after each placebo/treatment sessions all the patients received: optical coherence tomography (OCT), Best-Corrected Visual Acuity (BCVA) and Microperimetry (MP). RESULTS: no significant differences in the anatomical parameters were observed in the two groups. The MP mean sensitivity and the central visual function both far and near significantly improved in the treated group (respectively p < 0.001, p < 0.001). CONCLUSIONS: our pivotal demonstrated that the LED PBM delivered through our new device is a safe and effective tool for improving short-term visual function in patients affected by severe non-neovascular AMD.
RESUMO
This paper presents the analytical derivation of spreading resistance expressions for diverse geometries of a conducting probe submerged in a lossy medium. Resulting equations can be used to calibrate scanning impedance/scanning microwave microscopes operating in liquid. The expressions are systematically validated through numerical and experimental methods for the calibration of an inverted Scanning Microwave Microscope (iSMM) when operating in a lossy saline medium, such as Dulbecco's Modified Eagle Medium (DMEM), a widely used medium for supporting the growth of biological cells. The calibration process within DMEM plays an important role in the quantitative local evaluation of electromagnetic properties of biological samples under physiological conditions. Additionally, measurements are performed in distilled water for comparative analysis.
RESUMO
We have developed a photo-mobile polymer film, that combines organic and inorganic materials, to allow for controlled motion that can be triggered by light or heat. Our film is made using recycled quartz and consists of two layers: a multi-acrylate polymer layer and a layer containing oxidized 4-amino-phenol and N-Vinyl-1-Pyrrolidinone. The use of quartz in our film also gives it a high temperature resistance of at least 350 °C. When exposed to heat, the film moves in a direction that is independent of the heat source, due to its asymmetrical design. Once the heat source is removed, the film returns to its original position. ATR-FTIR measurements confirm this asymmetrical configuration. This technology may have potential applications in energy harvesting, due to the piezoelectric properties of quartz.
RESUMO
In this work, we study the light-induced changes of the rotational speed of a thin photomobile film using a single-axis acoustic levitator operating at 40 kHz. In our experiments, a 50 µm thick photomobile polymer film (PMP) is placed in one of the nodes of a stationary acoustic field. Under the action of the field, the film remains suspended in air. By externally perturbing this stable equilibrium condition, the film begins to rotate with its natural frequency. The rotations are detected in real time by monitoring the light of a low power He-Ne laser impinging on and reflected by the film itself. During the rotational motion, an external laser source is used to illuminate the PMP film; as a consequence, the film bends and the rotational speed changes by about 20 Hz. This kind of contactless long-distance interaction is an ideal platform for the development and study of many electro-optics devices in microgravity and low-friction conditions. In particular, we believe that this technology could find applications in research fields such as 3D dynamic displays and aerospace applications.
RESUMO
We report on highly transparent holographic phase transmission volume gratings recorded in the visible region at λ = 532 nm. The maximum measured diffraction efficiency is higher than 80% with a grating pitch of Λ≈ 300 nm and a refractive index modulation Δn ≈ 0.018. To obtain these results, we used a holographic mixture based on multi-reticulated acrylate and haloalkanes (1-bromo-butane and 1-bromo-hexane) and a synergic combination of camphore-quinone, which has a maximum absorbance at c.a. 470 nm, and R6G, here used as co-initiator, to efficiently initiate the photo-polymerization process. High transparent and high efficient holographic structures based on polymers can find applications in many research fields including integrated optics, sensors, high density data storage and security.
RESUMO
The integration of micro-optics in lab on a chip (LOCs) devices is crucial both for increasing the solid angle of acquisition and reducing the optical losses, aiming at improving the signal-to-noise ratio (SNR). In this work, we present the thriving combination of femtosecond laser irradiation followed by chemical etching (FLICE) technique with CO2 laser polishing and inkjet printing to fabricate in-plane, 3D off-axis reflectors, featuring ultra-high optical quality (RMS â¼3 nm), fully integrated on fused silica substrates. Such micro-optic elements can be used both in the excitation path, focusing an incoming beam in 3D, and in the acquisition branch, harvesting the optical signal coming from a specific point in space. The flexibility of the manufacturing process allows the realization of micro-optics with several sizes, shapes and their integration with photonic circuits and microfluidic networks.
RESUMO
We report on the realization of Distributed Feedback (DFB) lasing by a high-resolution reflection grating integrated in a Photomobile Polymer (PMP) film. The grating is recorded in a recently developed holographic mixture basically containing halolakanes/acrylates and a fluorescent dye molecule (Rhodamine 6G). The PMP-mixture is placed around the grating spot and a subsequent curing/photo-polymerization process is promoted by UV-irradiation. Such a process brings to the simultaneous formation of the PMP-film and the covalent link of the PMP-film to the DFB-grating area (PMP-DFB system). The PMP-DFB allows lasing action when optically pumped with a nano-pulsed green laser source. Moreover, under a low-power light-irradiation the PMP-DFB bends inducing a spatial readdressing of the DFB-laser emission. This device is the first example of a light-controlled direction of a DFB laser emission. It could represent a novel disruptive optical technology in many fields of Science, making feasible the approach to free standing and light-controllable lasers.
RESUMO
Holographic photomobile polymers (H-PMP) are a novel class of photomobile materials in which holograms can be optically recorded. They can be used in a large variety of applications, including optical switches and color selectors. In this work, we show one of the most important properties of the photomobile film, which is the photophobicity of the unpolymerized parts of the photomobile mixture. In order to investigate this property, we recorded a transmission phase grating on an H-PMP film, and used a different experimental technique to measure the diffraction efficiency, surface tension, and mixture properties. The results allowed for a better understanding of the mechanism of the light-controlled bending observed in these compounds.
RESUMO
In this work, we test the effectiveness of using highly transparent holographic phase reflection and transmission volume gratings based on multifunctional acrylates as linear compression and rotation sensors. The gratings are recorded in a holographic mixture based on multi-reticulated acrylate and haloalkanes. To activate the photo-polymerization process, we used a mixture of 6-oxocamphore and rhodamine 6G. The mixture is a simplified version of the mixture used in previous works and shows some interesting features mainly in connection with the different roles played by the rhodamine 6G dye at different writing wavelengths λ = 532 nm and λ = 460 nm. Regarding reflection gratings, the maximum achieved diffraction efficiency is ≈50% and their use as linear compression sensors produces a shift in the reflection peak of 2 nm. Following the removal of compression, the grating slowly returns to the initial state. Regarding transmission gratings, the maximum achieved diffraction efficiency is ≈45% and they demonstrate very high sensitivity to even small rotations in a free-standing configuration.
RESUMO
We report on the morphological, spectral and dynamical characterization of one-dimensional transmission holographic volume phase gratings, whose refractive index contrast and nanometric pitch are dynamically controlled by an incident laser light. The grating is obtained by the photo-polymerization of a recently developed photo-mobile holographic composite polymer material. The observed changes in the refractive index contrast and grating pitch strongly suggest that the reversible all-optical real-time modulation of the obtained diffraction efficiency is induced by nano-fluidics.
RESUMO
The present paper describes a novel implementation of the continuous phase shifting method (PSM), named heterodyne holography, in a scanning probe microscope configuration, able to retrieve the complex scattered field in on-axis configuration. This can be achieved by acquiring a continuous sequence of holograms at different wavelengths in just a single scan through the combination of scanning interference microscopy and a low-coherent signal acquired in the frequency domain. This method exploits the main advantages of the phase shifting technique and avoids some limits relative to off-axis holography in providing quantitative phase imaging.
RESUMO
In this study, UV irradiation was used to improve the response of indium oxide (In2O3) used as a CO sensing material for a resistive sensor operating in a low temperature range, from 25 °C to 150 °C. Different experimental conditions have been compared, varying UV irradiation mode and sensor operating temperature. Results demonstrated that operating the sensor under continuous UV radiation did not improve the response to target gas. The most advantageous condition was obtained when the UV LED irradiated the sensor in regeneration and was turned off during CO detection. In this operating mode, the semiconductor layer showed an apparent "p-type" behavior due to the UV irradiation. Overall, the effect was an improvement of the indium oxide response at 100 °C toward low CO concentrations (from 1 to 10 ppm) that showed higher results than in the dark, which is promising to extend the detection of CO with an In2O3-based sensor in the sub-ppm range.
RESUMO
Recently, it was shown that a Mie particle in an evanescent field ought to experience optical forces that depend on the helicity of the totally internally reflected beam. As yet, a direct measurement of such helicity-dependent forces has been elusive, as the widely differing force magnitudes in the three spatial dimensions place stringent demands on a measurement's sensitivity and range. In this study, we report the simultaneous measurement of all components of this polarization-dependent optical force by using a 3D force spectroscopy technique with femtonewton sensitivity. The vector force fields are compared quantitatively with our theoretical calculations as the polarization state of the incident light is varied and show excellent agreement. By plotting the 3D motion of the Mie particle in response to the switched force field, we offer visual evidence of the effect of spin momentum on the Poynting vector of an evanescent optical field.
RESUMO
Exosomes are nanovesicles known to mediate intercellular communication. Although it is established that zinc ions can act as intracellular signaling factors, the measurement of zinc in circulating nanovesicles has not yet been attempted. Providing evidence of the existence of this zinc fraction and methods for its measurement might be important to advance our knowledge of zinc status and its relevance in diseases. Exosomes from 0.5â¯ml of either fresh or frozen human plasma were isolated by differential centrifugation. A morphological and dimensional evaluation at the nanoscale level was performed by atomic force microscopy (AFM) and Transmission Electron Microscopy (TEM). Energy Dispersive X-Ray Microanalysis (EDX) revealed the elemental composition of exosomes and their respective total Zinc content on a quantitative basis. The zinc mole fraction (in at%) was correlated to the phosphorous mole fraction, which is indicative for exosomal membrane material. Both fresh (Zn/P 0.09⯱â¯0.01) and frozen exosomes (Zn/P 0.08⯱â¯0.02) had a significant zinc content, which increased up to 1.09⯱â¯0.12 for frozen exosomes when treated with increasing amounts of zinc (100-500⯵M; each pâ¯<â¯0.05). Interestingly, after zinc addition, the Calcium mole fractions decreased accordingly suggesting a possible exchange by zinc. In order to estimate the intra-exosomal labile zinc content, an Imaging Flow Cytometry approach was developed by using the specific membrane permeable zinc-probe Fluozin-3AM. A labile zinc content of 0.59⯱â¯0.27â¯nM was calculated but it is likely that the measurement may be affected by purification and isolation conditions. This study suggests that circulating nano-vesicular-zinc can represent a newly discovered zinc fraction in the blood plasma whose functional and biological properties will have to be further investigated in future studies.
Assuntos
Exossomos/química , Zinco/sangue , Humanos , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Tamanho da PartículaRESUMO
The extracellular guanosine 5'-triphosphate, GTP, has been demonstrated to be an enhancer of myogenic cell differentiation in a murine cell line, not yet in human muscle cells. Our hypothesis was that GTP could influence also human skeletal muscle regeneration, specifically in the first phases. We tested GTP stimulus on human muscle precursor cells established in culture by human satellite cells derived from Vastus Lateralis of three young male. Our data show that extracellular GTP (a) up-regulated miRNA (specifically miR133a and miR133b) and myogenic regulator factor and (b) induces human myogenic precursor cells to release exosomes stuffed with guanosine based molecules (mainly guanosine) in the extracellular milieu. We think that probably these exosomes could be addressed to influence by means of their content (mainly guanosine) in paracrine or autocrine manner the surrounding cells and/or at distance other muscles or tissues.
RESUMO
We examine the motion of periodically driven and optically tweezed microspheres in fluid and find a rich variety of dynamic regimes. We demonstrate, in experiment and in theory, that mean particle motion in 2D is rarely parallel to the direction of the applied force and can even exhibit elliptical orbits with nonzero orbital angular momentum. The behavior is unique in that it depends neither on the nature of the microparticles nor that of the excitation; rather, angular momentum is introduced by the particle's interaction with the anisotropic fluid and optical trap environment. Overall, we find this motion to be highly tunable and predictable.
RESUMO
A scanning optical microcavity is exploited to achieve lens-free 3D tomography of microfluidic channels. The microcavity, powered by a low-coherence source, is realized by approaching a cleaved fiber to few tens of micrometers over the sample. The interference of scattered waves inside the cavity shapes the transverse field distribution by focusing the beam and overcoming the diffraction limit due to the optical-fiber numerical aperture. The focusing effect is also preserved in the inner layers of the sample, allowing optical 3D tomography. Analysis of microfluidic channels was demonstrated through this noninvasive technique. Although the experimental setup recalls the well-known fiber-optic Fourier-domain common-path optical coherence tomography, the proposed method has intrinsic characteristics that distinguish it from the former one.
RESUMO
The mutual interference of light scattered inside an extrinsic Fabry-Perot microcavity, fed by a low-coherence light, is exploited to achieve infrared imaging in a liquid environment. The transverse field distribution inside a cavity is shaped by the effect of scattered interfering waves in a lens-free system. Reflectivity and contrast phase maps are extracted through the analysis of the cavity response in the time domain. This approach allows to conjugate noninvasivity, subdiffraction imaging, possible quantitative evaluation of dielectric constants and infrared spectroscopy, making it suitable for biological applications.
Assuntos
Raios Infravermelhos , Imagem Óptica/métodos , Mioblastos/citologia , Espalhamento de Radiação , ÁguaRESUMO
The exceptional interest in improving the limitations of data storage, molecular electronics and optoelectronics has promoted the development of an ever increasing number of techniques used to pattern polymers at micro and nanoscale. Most of them rely on atomic force microscopy to thermally or electrostatically induce mass transport, thereby creating topographic features. Here we show that the mechanical interaction between the tip of the atomic force microscope and the surface of π-conjugated polymeric films produces a local increase of molecular disorder, inducing a localized lowering of the semiconductor conductivity, not associated to detectable modifications in the surface topography. This phenomenon allows for the swift production of low-conductivity patterns on the film surface at a speed exceeding 20 µm s⻹; paths have a resolution in the order of the tip size (20 nm) and are detected by a conducting-atomic force microscopy tip in the conductivity maps.
RESUMO
BACKGROUND: The incidence of thyroid cancer (TC) has been increasing over the last 30 years in several countries, with some of the worldwide highest TC incidence rates (IRs) reported in Italy. The objectives of this study were to evaluate by histological subtypes the geographical heterogeneity of the incidence of TC in Italy and to analyze recent time trends for papillary thyroid carcinoma (PTC) in different cancer registries (CRs). METHODS: The study included cases of TC (<85 years of age) reported to 25 Italian CRs between 1991 and 2005. Age-standardized IRs were computed for all histological subtypes of TC according to CRs. Estimated annual percent change and joinpoint regression analysis were used for analysis of PTC. RESULTS: In women, IRs of PTC ranged between 3.5/100,000 in Latina and 8.5/100,000 in Sassari for the period 1991-1995 (a 2.4-fold difference) and between 7.3/100,000 in Alto Adige and 37.5/100,000 in Ferrara for 2001-2005 (a 5.1-fold difference). In men, IRs ranged between 0.7/100,000 in Latina and 3.4/100,000 in Sassari for the period 1991-1995 (a 4.9-fold difference) and between 2.0/100,000 (Alto Adige, Trento) and 10.6/100,000 in Ferrara for 2001-2005 (a 5.3-fold difference). In both sexes, IRs significantly higher than the pooled estimates emerged for the most recent period in the majority of CRs located within the Po River plain and in Latina, but they were lower in the Alpine belt. For women, CRs reported higher IRs than pool estimates showed, between 1991 to 2005, a significantly more marked annual percent change (+12%) than other CRs (+7%). For men the corresponding estimates were +11% and +8%. CONCLUSIONS: The distribution of PTC does not lend support to a role of environmental radiation exposure due to the Chernobyl fallout, iodine deficiency, or (volcanic) soils. Between 1991 and 2005, wide geographic variations in the incidence of PTC and heterogeneous upward trends emerged, suggesting that the heterogeneity was a relatively recent phenomenon; this appeared to be mainly explained by variations, at a local level, in medical surveillance.