Vitis vinifera Red Globe grape: In natura investigations on skin pigmentation using phase-resolved photoacoustic and TDDFT methods.

In this work we aimed to investigate the source of the Red Globe grape skin pigmentation. To achieve this goal, we used the phase-resolved photoacoustic technique to investigate the sample in natura and to access the phase-dependent absorbing entities. In addition, we used the time-dependent density functional theory (TDDFT) to contrast with our experimental spectroscopic results. We measured the absorption spectrum of the Red Globe grape in natura using the photoacoustic technique and recovered the main source pigmentation spectrum using the phase-resolved technique. Finally, using the TDDFT, we qualitatively analyzed the physical sources of the grape pigmentation and we found significant evidence that the main biomolecules responsible for the coloration of the grape are the cyanidin-3-O-glucoside and the peonidin-3-O-glucoside.

Technique for Darkening of Extracted Teeth Simulating Pulpal Necrosis Discoloration.

Background: The use of discolored teeth is required to test whitening products, and it is difficult to obtain them, given their scarcity. Objective: To present a technique for in vitro darkening of extracted teeth simulating pulpal necrosis discoloration. Materials and Methods: Hemolysates I and II from human blood were subjected or not to laser irradiation (442 nm) for 1 h. The concentration of oxyhemoglobin (O2Hb) was analyzed by ultraviolet/visible spectroscopy, and the conversion of O2Hb to methemoglobin (MetHb) by transmission spectroscopy was assessed immediately and after 3 and 40 days. For darkening evaluation, bovine incisors were divided into two groups (n = 25), and their pulp chambers were filled with hemolysate solution II (HSII) and hemolysate II solution + laser (HSII+L). After storage in artificial saliva for 40 days at 37°C, color changes were measured by a colorimeter and ΔE was compared with the NBS parameters. Data were analyzed using a mixed linear model (α=5%). Results: HSII+L presented the lowest O2Hb and higher MetHb. The conversion of O2Hb to MetHb in HSII+L was 42% higher than in HSII. Both groups were effective in darkening the teeth, according to the NBS. Darkening stabilized from day 35. HSII promoted a marked color difference. Conclusion: The proposed technique was effective in darkening the extracted teeth simulating necrosis discoloration for in vitro models.

Studies of the early stages of the dynamic setting process of chemically activated restorative glass-ionomer cements.

OBJECTIVE: To evaluate the early stages of the setting process of chemically activated restorative glass-ionomer cements (GICs). MATERIAL AND METHODS: Five GICs were evaluated (n = 5): Equia Forte (GC), Equia Forte HT (GC), Ketac Universal (3M ESPE), Maxxion R (FGM) and Riva Self Cure (SDI) by Thermography, Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) and Gillmore needle indentation mechanical testing. The FTIR-ATR spectra showed the formation of metal carboxylates within the cements and enabled the stabilization time (ST) to be determined and the thermographic camera measured the temperature field images in the sample. Data were statistically analyzed by ANOVA and Tukey-Kramer (α = 5%). RESULTS: The Gillmore needle test showed that the order of hardening was opposite to the order of ST values determined by FTIR. The results with the thermographic camera showed two stages of temperature variation, which coincided with the evolution of specific infrared bands. The exception was Maxxion R, which showed only a single step change in temperature. CONCLUSION: The early stages of the GIC setting reaction show temperature changes, both endothermic and exothermic, at specific times, confirming the occurrence of individual chemical reactions. The early setting involves reactions other than carboxylate formation.Significance: This study gives further detail of the early stages of the setting of GICs, and past research regarding the setting reaction of GIC.

The correlation of physicochemical properties of edible vegetable oils by chemometric analysis of spectroscopic data.

This work aimed to investigate and compare the composition and the physicochemical properties of 18 different sources of edible vegetable oils. A systematic study on the correlation between composition and physical properties was performed using Fourier Transform Infrared (FTIR) Spectroscopy and fatty acid chromatographic analysis. Principal component analysis of FTIR spectra is performed to classify edible oils concerning their physical properties. The results demonstrate the potentiality of the method associated with multivariate statistics analysis as powerful, fast, and non-destructive tools for characterization and quality control of edible vegetable oils.

True absolute determination of photoluminescence quantum yields by coupling multiwavelength thermal lens and photoluminescence spectroscopy.

Photoluminescence quantum yields denote a critical variable to characterise a fluorophore and its potential performance. Their determination, by means of methodologies employing reference standard materials, inevitably leads to large uncertainties. In response to this, herein we report for the first time an innovative and elegant methodology, whereby the use of neat solvent/reference material required by thermal lens approaches is eliminated by coupling it to photoluminescence spectroscopy, allowing for the discrimination between materials with similar photoluminescence quantum yields. To achieve this, both radiative and non-radiative transitions are simultaneously measured using a photoluminescence spectrometer coupled to a multiwavelength thermal lens spectroscopy setup in a mode-mismatched dual-beam configuration, respectively. The absorption factor independent ratio of the thermal lens and photoluminescence signals can then be used to determine the fluorescence quantum yield both accurately and precisely. We validated our reported method using rhodamine 6G and further applied it to three novel structurally related diketopyrrolopyrrole based materials, which, in contrast to results obtained by other methods, unveiled significant differences in their photoluminescence quantum yields.

Thermal-wave resonant cavity signal processing.

The thermal-wave resonant cavity (TWRC) technique has been used for thermal diffusivity measurements by many researchers. This study aims to reduce the uncertainty associated with TWRC signal processing (curve fitting) by means of numerical simulation and experimental verification. Simulations show that the plot of signal amplitude versus cavity length can be fitted to a simplified model reported previously when the initial fitting position is at least twice the thermal-wave diffusion length (2 µg), and that the uncertainty caused by different end positions is negligible in the range of 6-10 µg. Upon consideration of the simulation results, signal-to-noise ratio, and clearly defined amplitude curve shape, fitting ranges of about 2.2-8.0 µg and 2.2-8.7 µg were chosen for the experimental data. Thermal diffusivity values (1.438 ± 0.001) × 10-7 and (1.436 ± 0.001) × 10-7 m2 s-1, respectively, were obtained for distilled water, in excellent agreement with the accepted literature value. The ratio of standard deviation to the mean value is smaller than 0.07%, one order of magnitude lower than typical results reported in the literature. Similar simulation results were obtained for air and methanol as intra-cavity samples.

Influence of external energy sources on the dynamic setting process of glass-ionomer cements.

OBJECTIVE: To evaluate the influence of external energy sources on the dynamic setting process of glass-ionomer restorative materials. METHODS: Eighteen brands of GIC were studied: Bioglass R (Biodinâmica; G1), Chemfil Rock (Dentsply; G2), Equia Forte (GC; G3), Gold Label 2 (GC; G4), Gold Label 9 (GC; G5), Glass Ionomer Cement Type II - (Shofu; G6), Ionglass R (Maquira; G7), Ion Z (FGM; G8), Ionomaster (Wilcos; G9), Ionofil Plus (Voco; G10), Ionostar Plus (Voco; G11), Ketac Molar easymix (3M ESPE; G12), Magic Glass R (Vigodent; G13), Maxxion R (FGM; G14), Riva Self Cure (SDI; G15), Vidrion R (SS White; G16), Vitro Fil R (Nova DFL; G17) and Vitro Molar (Nova DFL; G18). LED, halogen light or ultrasound (n=20 for each set) applied for 30s was used to activate setting, and a control group of each material was allowed to set without activation. Samples were analyzed by FTIR spectroscopy using the ratio of intensities of bands at 1637cm-1 (carboxylate) and 1720cm-1 (carbonyl) as a function of time. Means and standard deviations were subjected to ANOVA and Tukey tests (p<0.05). RESULTS: All three activation modes significantly reduced the time at which the carboxylate content became stable in G2, G4, G5, G6, G8, G10, G14, G16, G17 and G18. By contrast, in G1, G7, G12 and G15 no activation source had any significant effect (p>0.05). SIGNIFICANCE: External activation sources, namely LED, halogen light and ultrasound, typically but not always increase the setting rate of restorative GICs.

Fusarium oxysporum is an onychomycosis etiopathogenic agent.

AIM: To evaluate and characterize the etiopathogenesis of the fusarial onychomycosis in an ex vivo study through fragments of sterile human nail, without the addition of any nutritional source. MATERIALS & METHODS: The infection and invasion of Fusarium oxysporum in the nail were evaluated by scanning electron microscopy (SEM), CFU, matrix, histopathology and Fourier Transform Infrared Spectrometer coupled to an equipment with diamond accessory (FTIR-ATR). RESULTS: F. oxysporum infected and invaded across the nail, regardless of application face. However, the dorsal nail surface was the strongest barrier, while the ventral was more vulnerable to infection and invasion process. The fungal-nail interaction resulted in the formation of a dense biofilm. CONCLUSION: F. oxysporum infect and invade the healthy human nail, resulting in biofilm formation. Therefore, F. oxysporum is likely a primary onychomycosis agent.

Propolis Extract for Onychomycosis Topical Treatment: From Bench to Clinic.

Onychomycosis is a chronic fungal infection of nails, commonly caused by dermatophyte fungi, primarily species of Trichophyton. Because of the limited drug arsenal available to treat general fungal infections and the frequent failure of onychomycosis treatment, the search for new therapeutic sources is essential, and topical treatment with natural products for onychomycosis has been encouraged. Propolis, an adhesive resinous compound produced by honeybees (Apis mellifera), has shown multiple biological properties including significant antifungal and anti-biofilm activities in vitro. In spite of promising in vitro results, in vivo results have not been reported so far. This study assessed an ethanol propolis extract (PE) as a topical therapeutic option for onychomycosis, including its characterization in vitro and its applicability as a treatment for onychomycosis (from bench to clinic). The in vitro evaluation included analysis of the cytotoxicity and the antifungal activity against the planktonic cells and biofilm formed by Trichophyton spp. We also evaluated the capacity of PE to penetrate human nails. Patients with onychomycosis received topical PE treatments, with a 6-month follow-up period. The results of the in vitro assays showed that PE was non-toxic to the cell lines tested, and efficient against both the planktonic cells and the biofilm formed by Trichophyton spp. The results also showed that PE is able to penetrate the human nail. The results for PE applied topically to treat onychomycosis were promising, with complete mycological and clinical cure of onychomycosis in 56.25% of the patients. PE is an inexpensive commercially available option, easy to obtain and monitor. Our results indicated that PE is a promising natural compound for onychomycosis treatment, due to its ability to penetrate the nail without cytotoxicity, and its good antifungal performance against species such as Trichophyton spp. that are resistant to conventional antifungals, both in vitro and in patients.

Evidence of anti-inflammatory effect and percutaneous penetration of a topically applied fish oil preparation: a photoacoustic spectroscopy study.

This paper investigates the topical anti-inflammatory effect of a fish oil preparation (FOP) in a croton oil (CO) model of skin inflammation. The photoacoustic spectroscopy (PAS) was applied to estimate the percutaneous penetration of the FOP and as a model to evaluate the topical inflammatory response. After applying CO, the groups of mice received a topical application of a FOP on the left ear. The right ear received the vehicle that was used to dilute the CO. After 6 h, ear tissue was collected to determine the percent inhibition of edema, myeloperoxidase (MPO) activity, and cytokine levels and to perform PAS measurements. Treatment with FOP reduced edema and MPO activity, which was at least partially attributed to a decrease in the levels of tumor necrosis factor, interleukin- 1 ? , interleukin-6, keratinocyte-derived chemokine, and monocyte chemoattractant protein-1. The topically applied FOP penetrated into the tissue and decreased the area of the bands that characterize inflamed tissue. The present results demonstrated the topical anti-inflammatory effect of the FOP. PAS suggests that FOP anti-inflammatory activity is linked with its ability to penetrate through the skin.

Nectandra falcifolia: potential phytopharmaceutical for skin damage protection designed by statistical approach and characterized by photoacoustic spectroscopy

AbstractPhytopharmaceutical products are being used in the treatment and prevention of health problems. Nowadays, the development and evaluation of novel pharmaceutical products is expensive and time consuming. A statistical approach is a good tool for optimal development processes. Nectandra falcifolia (Nees) J.A. Castigl. ex Mart. Crov. & Piccinini, Lauraceae, a Brazilian species, is reported as anti-inflammatory, anti-leishmanial and anti-microbial. However, there is little known about its chemical composition. For other species of Nectandra genus, the presence of antioxidant compounds is reported. In order to optimize the process of obtaining extract with high antioxidant activity, different extraction conditions were tested following a statistical approach. Two sequential experimental designs were used – first, a factorial 23 design, followed by central composite 22. The extracts manufactured by these experimental statistical matrixes had their antioxidant activity and phenolic contents quantified and the response surface plots were fitted in quadratic models and they predicted the best extraction condition for the best antioxidant activity. This standardized extract and its antioxidant activity were better evaluated by two complementary tests (ABTS and Burst respiratory). A topical formulation containing 1% (w/w) of standardized extract was prepared and used for an in vivo skin permeation study using a two-dose application. The photoacoustic spectroscopy was used to analyze the samples from the permeation study and the composition profile of standardized extract. In rat skin samples, the data demonstrated that for the higher dose of topical formulation (5 g/cm2), the standardized extract could cross skin and be seen in epidermis and dermis. This was not the case for the lower dose (2 g/cm2) which was only present in the epidermis. This information suggests that this novel standardized extract of N. falcifoliacould be explored for skin damage prevention or treatment for diseases developed by oxidative damage.

Evaluation of Photoprotective Potential and Percutaneous Penetration by Photoacoustic Spectroscopy of the Schinus terebinthifolius Raddi Extract.

Schinus terebinthifolius is a plant rich in phenolic compounds, which have antioxidant properties and can provide new opportunities for treatment and prevention of diseases mediated by ultraviolet radiation like photoaging and skin cancer. The aim of this study was to evaluate the photoprotective potential and ex vivo percutaneous penetration of the crude extract of Schinus terebinthifolius leaves. The extract was tested for antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and ß-carotene bleaching test. The sun protection factor was also evaluated. The ex vivo skin permeation of the emulsion and gel formulations were assayed. Fractionation of the extract resulted in gallic acid, ethyl gallate and a mixture of flavonoids, suggesting derivatives of quercetin and myricetin. The phenolic content of the extract was 384.64 ± 2.60 mg GAE g(-1) extract. The antioxidant activity was superior to butylated hydroxytoluene, in DPPH method, and ascorbic acid and rutin, in ß-carotene bleaching assay. The extract showed UV absorption with photoprotector potential in the UVB region. The photoacoustic spectroscopy measurements confirmed absorption in the UV region and topical application of the formulations caused no histological changes in the rats' skin. These results suggest that the crude extract of Schinus terebinthifolius leaves may be a promising natural sunscreen product.

Combined photothermal lens and photothermal mirror characterization of polymers.

We propose a combined thermal lens and thermal mirror method as concurrent photothermal techniques for the physical characterization of polymers. This combined method is used to investigate polymers as a function of temperature from room temperature up to 170 °C. The method permits a direct determination of thermal diffusivity and thermal conductivity. Additional measurements of specific heat, linear thermal expansion, and temperature-dependent optical path change are also performed. A complete set of thermal, optical, and mechanical properties of polycarbonate and poly (methyl methacrylate) samples are obtained. Methods presented here can be useful for in situ characterization of semitransparent materials, where fast and non-contacting measurements are required.

Unravelling the effects of radiation forces in water.

The effect of radiation forces at the interface between dielectric materials has been a long-standing debate for over a century. Yet there has been so far only limited experimental verification in complete accordance with the theory. Here we measure the surface deformation at the air-water interface induced by continuous and pulsed laser excitation and match this to rigorous theory of radiation forces. We demonstrate that the experimental results are quantitatively described by the numerical calculations of radiation forces. The Helmholtz force is used for the surface radiation pressure. The resulting surface pressure obtained is consistent with the momentum conservation using the Minkowski momentum density expression assuming that the averaged momentum per photon is given by the Minkowski momentum. Considering the total momentum as a sum of that propagating with the electromagnetic wave and that deposited locally in the material, the Abraham momentum interpretation also appears to be appropriate.

Crude extract of Fusarium oxysporum induces apoptosis and structural alterations in the skin of healthy rats.

We evaluate the biological and physicochemical effects of a Fusarium oxysporum crude extract (CE) on the skin of healthy rats. The CE is topically applied and subsequently the skin is collected after 3, 6, 12, and 24 h. The samples are analyzed by Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) and histomorphometric analysis. Terminal dUTP nick end labeling (TUNEL assay) is performed to detect both the cells in apoptosis and proliferation. There is a thickening of the epidermis after 6, 12, and 24 h and dermis after 12 and 24 h of CE application. A reduction of the dermis thickness is observed at 3 and 6 h. The treated skin shows higher labeling intensity by TUNEL at 3 h, while a higher intensity by proliferating cell nuclear antigen occurs at 3 and 12 h. FTIR-PAS data support the histology observations showing an increase in the absorption peaks in the dermis after the application of the CE. F. oxysporum CE permeated through the epidermis and the dermis, reaching the subcutaneous tissue, inducing cell apoptosis, and causing physicochemical changes in the organic molecules located in the dermis. This is the first known study associating histopathological and physical chemistry changes on healthy skin after the application of F. oxysporum CE.

Pulsed-laser time-resolved thermal mirror technique in low-absorbance homogeneous linear elastic materials.

A theoretical model for a time-resolved photothermal mirror technique using pulsed-laser excitation was developed for low absorption samples. Analytical solutions to the temperature and thermoelastic deformation equations are found for three characteristic pulse profiles and are compared to finite element analysis methods results for finite samples. An analytical expression for the intensity of the center of a continuous probe laser at the detector plane is derived using the Fresnel diffraction theory, which allows modeling of experimental results. Experiments are performed in optical glasses, and the models are fitted to the data. The parameters of the fit are in good agreement with previous literature data for absorption, thermal diffusion, and thermal expansion of the materials tested. The combined modeling and experimental techniques are shown to be useful for quantitative determination of the physical properties of low absorption homogeneous linear elastic material samples.

Ultraviolet (UVB and UVA) photoprotector activity and percutaneous penetration of extracts obtained from Arrabidaea chica.

The aim of this work is to investigate the photoprotection activity and toxicity level of formulations containing the extract and its fractions obtained from leaves of Arrabidaea chica. The ex vivo percutaneous penetration of the extract was evaluated using the photoacoustic spectroscopy technique. The formulation presented optical absorption in the ultraviolet region, including UVA and UVB. This formulation was obtained without adding inorganic UV filters, as is frequently used in commercial sunscreens. The results showed a penetration rate similar to those of commercial sunscreens with its presence on the skin surface at least 180 min after the application. This formulation presented no toxic effects evaluated using hematological, biochemical, and histological assays. The results suggest that the formulation from the leaves of A. chica provides substantial protection against UVA + UVB radiation with a possible advantage of being natural and free of inorganic compounds compared with the majority of available commercial sunscreens.

Morphological and structural changes in lung tissue infected by Paracoccidioides brasiliensis: FTIR photoacoustic spectroscopy and histological analysis.

This study evaluated physical, chemical and morphological changes in lungs of mice infected with Paracoccidioides brasiliensis. The animals were inoculated with 0.1 mL of fungal suspension of the P. brasiliensis 18 isolate and were euthanized 1, 2, 4 and 8 weeks after inoculation. The upper left lobe of the lung was isolated, fixed and processed for paraffin embedding. The sections were stained with H&E for histopathological study, with Gomori-Grocott to locate and identify the fungus, and with TUNEL immunostaining to detect the occurrence of programmed cell death. The lower and middle right lobes were analyzed by Fourier Transform Infrared Photoacoustic Spectrocopy (FTIR-PAS) to investigate physical and chemical features of the infected lungs. The results showed that lungs infected by P. brasiliensis underwent structural changes that varied according to the time period analyzed, and that changes in the absorption bands of different chemical groups resulted from these morphological changes. The results suggest that the combination of FTIR-PAS spectroscopy with morphological evaluation is an effective procedure for the study of paracoccidioidomycosis, one of the most important systemic mycoses that can damage the lung architecture and consequently impair the respiratory function.

Photosensitizer and light diffusion through dentin in photodynamic therapy.

Photodynamic therapy has been considered a potential antimicrobial modality against oral infections, including dental caries. A model to estimate the penetration of both photosensitizers and light through human dentin, a factor of interest in photodynamic therapy, is proposed. The photoacoustic spectroscopy technique was used to evaluate in vitro dentin permeability of three different photosensitizers. Using the dentin optical absorption and scattering coefficients, it was possible to propose a semi-quantitative model predicting both photosensitizer and light doses within dentin. The graphic illustrations obtained provided guidelines that may be useful in photodynamic therapy protocols used as antimicrobial tools in caries lesions.

A simplified model for thermal-wave cavity self-consistent measurement of thermal diffusivity.

A simplified theoretical model was developed for the thermal-wave cavity (TWC) technique in this study. This model takes thermal radiation into account and can be employed for absolute measurements of the thermal diffusivity of gas and liquid samples without any knowledge of geometrical and thermal parameters of the components of the TWC. Using this model and cavity-length scans, thermal diffusivities of air and distilled water were accurately and precisely measured as (2.191 ± 0.004) × 10(-5) and (1.427 ± 0.009) × 10(-7) m(2) s(-1), respectively, in very good agreement with accepted literature values.