Preparação e caracterização óptica de filmes de ORMOSIL obtidos via processo sol-gel dopados com azocorantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise diferencial da potência máxima gerada por um sistema solar fotovoltaico

The Earth receives annually 1,5.1018 kWh of solar energy, which corresponds to 1000 times the world energy consumption in this period. This fact comes out that, besides being responsible for the maintenance of life on Earth, the solar radiation is in an inexhaustible energy source, with an enormous potential for use by systems capture and conversion into another form of energy. In many applications of low power systems that convert light directly into electricity, called photovoltaic advantageously replace other means of production processes, where its distribution is very significant. The determination of the power generated by such a system is of paramount importance for the design energy of its implementation and evaluation of the system itself. This study aims to determine a relationship between the maximum power generated by solar photovoltaic and characteristic parameters of the generator. This relationship allows to evaluate the performance of such a system. For simulations of the developed equations were used 3 photovoltaic modules with an output of 100 Wp each, and data collection was performed during one year by enrolling in addition to meteorological data, solar irradiance incident on the modules.

Evolução diurna e anual da frequência das coberturas de céu em Botucatu/SP

This work presents an analysis of the pattern variation of the sky conditions in Botucatu/SP. The classification was based on the clarness index KT. It was used in the classification a database of global solar irradiance in the horizontal, measured at Radiometric Station of UNESP in Botucatu (latitude 22.85°S, longitude 48.43°W, altitude 786 m) from 1996 to 2005. We analyzed the variations in frequency, during the photoperiod and over the year, of the sky conditions: I - Cloudy (KT < 0.35); II - party cloudy with dominance for the diffuse (0.35 < 0.55 < KT)) III - party cloudy with dominance for the clear (0.55 < KT < 0.65) and IV - clear (KT > 0.65). The frequency of sky conditions I and II are higher during the rainy season of the year and in hours close to sunrise and sunset. And it is lower during the dry season an in hours near noon, in wich there is a predominance of sky conditions III and IV. The monthly hourly frequency of sky condition I ranged from 46,91% of the photoperiod in January to 25.27% in August. And the frequency monthly daily ranged from nine days in January to three days in August. To the sky condition IV, the frequency monthly hourly ranged from 38.81% of the photoperiod in August to 18.17% im January. And the frequency monthly daily ranged from 17 days in August to three days in January.

Utilização do método numérico interpolador de Lagrange para correção de bases de dados de radiometria solar

This work explores the suitability of the Lagrange interpolating polynomial as a tool to estimate and correct solar databases. From the knowledge of the irradiance distribution over a day, a portion of it was removed for applying Lagrange interpolation polynomial. After generation of the estimates by interpolation, the assessment was made by MBE and RMSE statistical indicators. The application of Lagrange interpolating generated the following results: underestimation of 0.27% (MBE = -1.83 W/m2) and scattering of 0.51% (RMSE = 3.48 W/m2).

Effects of UV-B radiation on the antagonistic ability of Clonostachys rosea to Botrytis cinerea on strawberry leaf disc

Human activities are altering the concentrations of ozone in the troposphere and hence in the incidence of ultraviolet-B (UV-B) on Earth’s surface. Although representing only five percent of UV-B radiation striking the Earth's surface, this radiation has the potential to cause effects on biologically active molecules. Sensitivity to UV-B radiation is one of the limitations of biological control of plant pathogens in the field. The objectives of this work were to evaluate the effects of UV-B on several isolates of Clonostachys rosea, and the ability of an isolate of C. rosea, previously selected for its tolerant to UV-B radiation, to control Botrytis cinerea on strawberry leaves in controlled conditions (strawberry leaf discs). The germination of C. rosea conidia was inversely proportional to the irradiance. The most tolerant strain (LQC62) had relative germination of about 60% after irradiation of 4.2kJ/m2, and this strain was selected to be used in the subsequent studies. The data showed that even with exposure to UV-B radiation, C. rosea LQC62 controlled the pathogen. Conidial concentrations of strain LQC62 above 105 conidia/ml showed higher tolerance to UV-B radiation and increased ability to control more than 75% of the B. cinerea even with exposure to radiation. According to our results, in addition to showing less growth under UV-B, conidia of C. rosea had lower antagonistic ability. Further studies are needed to observe the tolerance of B. cinerea conidia to UV-B radiation and thereby prove that an environment with increased UV-B radiation may be favoring the pathogen due to a lower ability of C. rosea to control the pathogen in conditions of increased UV-B.

Effects of abiotic factors on growth and chemical defenses in cultivated clones of Laurencia dendroidea J. Agardh (Ceramiales, Rhodophyta)

Laurencia dendroidea shows high inter- and intrapopulation variability in the amount of the sesquiterpene elatol, caused by genetic variation as well as environmental factors. To test the independent effect of physical and nutritional conditions, the growth and the levels of elatol in L. dendroidea clones were evaluated under different conditions of temperature, salinity, irradiance, and culture medium in the laboratory. Growth of L. dendroidea was clearly affected by all these factors, but elatol levels were influenced only by temperature and salinity. Better conditions for growth did not produce a similar effect on elatol production in L. dendroidea, contradicting the carbon/nutrient balance and growth/differentiation balance models. On the contrary, severe conditions of temperature and salinity promoted a decrease in elatol levels, as predicted by the environmental stress model. Our results using clones indicated that abiotic factors clearly take part in fostering chemical variations observed in natural populations, in addition to genetic factors, and can promote differential susceptibility of plant specimens to natural enemies.

The role of clouds in improving the regression model for hourly values of diffuse solar radiation

The study introduces a new regression model developed to estimate the hourly values of diffuse solar radiation at the surface. The model is based on the clearness index and diffuse fraction relationship, and includes the effects of cloud (cloudiness and cloud type), traditional meteorological variables (air temperature, relative humidity and atmospheric pressure observed at the surface) and air pollution (concentration of particulate matter observed at the surface). The new model is capable of predicting hourly values of diffuse solar radiation better than the previously developed ones (R-2 = 0.93 and RMSE = 0.085). A simple version with a large applicability is proposed that takes into consideration cloud effects only (cloudiness and cloud height) and shows a R-2 = 0.92. (C) 2011 Elsevier Ltd. All rights reserved.

Influence of temperature, light and nutrients on the growth rates of the macroalga Gracilaria domingensis in synthetic seawater using experimental design

In the present study, the daily relative growth rates (DRGR, in percent per day) of the red macroalga Gracilaria domingensis in synthetic seawater was investigated for the combined influence of five factors, i.e., light (L), temperature (T), nitrate (N), phosphate (P), and molybdate (M), using a statistical design method. The ranges of the experimental cultivation conditions were T, 18-26A degrees C; L, 74-162 mu mol photons m(-2) s(-1); N, 40-80 mu mol L-1; P, 8-16 mu mol L-1; and M, 1-5 nmol L-1. The optimal conditions, which resulted in a maximum growth rate of a parts per thousand yen6.4% d(-1) from 7 to 10 days of cultivation, were determined by analysis of variance (ANOVA) multivariate factorial analysis (with a 2(5) full factorial design) to be L, 74 mu mol photons m(-2) s(-1); T, 26A degrees C; N, 80 mu mol L-1; P, 8 mu mol L-1; and M, 1 nmol L-1. In additional, these growth rate values are close to the growth rate values in natural medium (von Stosch medium), i.e., 6.5-7.0% d(-1). The results analyzed by the ANOVA indicate that the factors N and T are highly significant linear terms, X (L), (alpha = 0.05). On the other hand, the only significant quadratic term (X (Q)) was that for L. Statistically significant interactions between two different factors were found between T vs. L and N vs. T. Finally, a two-way (linear/quadratic interaction) model provided a quite reasonable correlation between the experimental and predicted DRGR values (R (adjusted) (2) = 0.9540).

Femtosecond laser induced synthesis of Au nanoparticles mediated by chitosan

This paper reports the synthesis of Au nanoparticles by 30-fs pulses irradiation of a sample containing HAuCl4 and chitosan, a biopolymer used as reducing agent and stabilizer. We observed that it is a multi-photon induced process, with a threshold irradiance of 3.8 x 10(11) W/cm(2) at 790 nm. By transmission electron microscopy we observed nanoparticles from 8 to 50 nm with distinct shapes. Infrared spectroscopy indicated that the reduction of gold and consequent production of nanoparticles is related to the fs-pulse induced oxidation of hydroxyl to carbonyl groups in chitosan. (C) 2011 Optical Society of America

Photodiagnosis and treatment of condyloma acuminatum using 5-aminolevulinic acid and homemade devices

Background: The objective of this study was to improve the feasibility of applying topic 5-aminolevulinic acid (ALA) in photodiagnosis (PD) and treatment of condyloma caused by human papillomavirus (HPV) using two homemade handheld devices and to discuss the photodynamic therapy (PDT) as a suitable alternative for each of the cases studied. Both, protoporphyrin IX production and photodegradation were analyzed, and the pain experienced during the illumination was correlated with the light intensities. Methods: A total of 40 women with different grades of lesions caused by HPV were chosen from patients of the School of Medicine of Ribeirao Preto (University of Sao Paulo) and of the Unit of Public Health of Araraquara, Sao Paulo. Results: We did not encounter any unexpected difficulties using our devices during the treatment. The existence of an easily observable reddish fluorescence with large intensity concentrated on the Lesions is the clinical indication of the penetration and the selective concentration of protoporphyrin IX in the clinical and subclinical lesions rather than in the healthy tissue. The aesthetic results were much better than those obtained by conventional techniques as surgery or cryogenics, with no recurrence reported after two years of treatment. Conclusions: Our results are proof for the various advantages using ALA cream for the PD and PDT in many different cases of condyloma by HPV. This study will be continued to investigate the PpIX photobleaching and the irradiance and fluence rate to optimize conducting the clinical trials, to improve the devices and therefore increase the treatment response. (c) 2011 Elsevier B.V. All rights reserved.

Degradation of [D-Leu]-Microcystin-LR by solar heterogeneous photocatalysis (TiO2)

The present study investigates the use of solar heterogeneous photocatalyis (TiO2) for the destruction of [D-Leu]-Microcystin-LR, powerful toxin of widespread occurrence within cyanobacteria blooms. We extracted [D-Leu]-Microcystin-LR from a culture of Microcystis spp. and used a flat plate glass reactor coated with TiO2 (Degussa, P25) for the degradation studies. The irradiance was measured during the experiments with the aid of a spectroradiometer. After the degradation experiments, toxin concentrations were determined by HPLC and mineralization by TOC analyses. Acute and chronic toxicities were, quantified using mice and phosphatase inhibition in vitro assays, respectively. According to the performed experiments, 150 min were necessary to reduce the toxin concentration to the WHO's guideline for drinking water (from 10 to 1 mu g L-1) and to mineralize 90% of the initial carbon content. Another important finding is that solar heterogeneous photocatalysis was a destructive process indeed, not only for the toxin, but also for the other extract components and degradation products generated. Moreover, toxicity tests using mice have shown that the acute effect caused by the initial sample was removed. However, tests using the phosphatase enzyme indicated that it may be formed products capable of inducing chronic effects on mammals. The performed experiments indicate the feasibility of using solar heterogeneous photocatalysis for treating contaminated water with [D-Leu]-Microcystin-LR, not only due to its destruction, but also to the significant removal of organic matter and acute toxicity that can be achieved. (C) 2012 Elsevier Ltd. All rights reserved.

THE INFRARED COLORS OF THE SUN

Solar infrared colors provide powerful constraints on the stellar effective temperature scale, but they must be measured with both accuracy and precision in order to do so. We fulfill this requirement by using line-depth ratios to derive in a model-independent way the infrared colors of the Sun, and we use the latter to test the zero point of the Casagrande et al. effective temperature scale, confirming its accuracy. Solar colors in the widely used Two Micron All Sky Survey (2MASS) JHK(s) and WISE W1-4 systems are provided: (V - J)(circle dot) = 1.198, (V - H)(circle dot) = 1.484, (V - K-s)(circle dot) = 1.560, (J - H)(circle dot) = 0.286, (J - K-s)(circle dot) = 0.362, (H - K-s)(circle dot) = 0.076, (V - W1)(circle dot) = 1.608, (V - W2)(circle dot) = 1.563, (V - W3)(circle dot) = 1.552, and (V - W4)(circle dot) = 1.604. A cross-check of the effective temperatures derived implementing 2MASS or WISE magnitudes in the infrared flux method confirms that the absolute calibration of the two systems agrees within the errors, possibly suggesting a 1% offset between the two, thus validating extant near-and mid-infrared absolute calibrations. While 2MASS magnitudes are usually well suited to derive T-eff, we find that a number of bright, solar-like stars exhibit anomalous WISE colors. In most cases, this effect is spurious and can be attributed to lower-quality measurements, although for a couple of objects (3%+/- 2% of the total sample) it might be real, and may hint at the presence of warm/hot debris disks.

Effects of the combination of low-level laser irradiation and recombinant human bone morphogenetic protein-2 in bone repair

Low-level laser irradiation (LLLI) and recombinant human bone morphogenetic protein type 2 (rhBMP-2) have been used to stimulate bone formation. LLLI stimulates proliferation of osteoblast precursor cells and cell differentiation and rhBMP-2 recruits osteoprogenitor cells to the bone healing area. This in vivo study evaluated the effects of LLLI and rhBMP-2 on the bone healing process in rats. Critical bone defects were created in the parietal bone in 42 animals, and the animals were divided into six treatment groups: (1) laser, (2) 7 mu g of rhBMP-2, (3) laser and 7 mu g of rhBMP-2, (4) 7 mu g of rhBMP-2/monoolein gel, (5) laser and 7 mu g rhBMP-2/monoolein gel, and (6) critical bone defect controls. A gallium-aluminum-arsenide diode laser was used (wavelength 780 nm, output power 60 mW, beam area 0.04 cm(2), irradiation time 80 s, energy density 120 J/cm(2), irradiance 1.5 W/cm(2)). After 15 days, the calvarial tissues were removed for histomorphometric analysis. Group 3 defects showed higher amounts of newly formed bone (37.89%) than the defects of all the other groups (P < 0.05). The amounts of new bone in defects of groups 1 and 4 were not significantly different from each other (24.00% and 24.75%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). The amounts of new bone in the defects of groups 2 and 5 were not significantly different from each other (31.42% and 31.96%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). Group 6 defects had 14.10% new bone formation, and this was significantly different from the amounts in the other groups (P < 0.05). It can be concluded that LLLI administered during surgery effectively accelerated healing of critical bone defects filled with pure rhBMP-2, achieving a better result than LLLI alone or the use of rhBMP-2 alone.

The effect of low-level laser irradiation (In-Ga-Al-AsP - 660 nm) on melanoma in vitro and in vivo

Abstract Background It has been speculated that the biostimulatory effect of Low Level Laser Therapy could cause undesirable enhancement of tumor growth in neoplastic diseases. The aim of the present study is to analyze the behavior of melanoma cells (B16F10) in vitro and the in vivo development of melanoma in mice after laser irradiation. Methods We performed a controlled in vitro study on B16F10 melanoma cells to investigate cell viability and cell cycle changes by the Tripan Blue, MTT and cell quest histogram tests at 24, 48 and 72 h post irradiation. The in vivo mouse model (male Balb C, n = 21) of melanoma was used to analyze tumor volume and histological characteristics. Laser irradiation was performed three times (once a day for three consecutive days) with a 660 nm 50 mW CW laser, beam spot size 2 mm2, irradiance 2.5 W/cm2 and irradiation times of 60s (dose 150 J/cm2) and 420s (dose 1050 J/cm2) respectively. Results There were no statistically significant differences between the in vitro groups, except for an increase in the hypodiploid melanoma cells (8.48 ± 1.40% and 4.26 ± 0.60%) at 72 h post-irradiation. This cancer-protective effect was not reproduced in the in vivo experiment where outcome measures for the 150 J/cm2 dose group were not significantly different from controls. For the 1050 J/cm2 dose group, there were significant increases in tumor volume, blood vessels and cell abnormalities compared to the other groups. Conclusion LLLT Irradiation should be avoided over melanomas as the combination of high irradiance (2.5 W/cm2) and high dose (1050 J/cm2) significantly increases melanoma tumor growth in vivo.

How low-level laser therapy can change mechanical properties of cells.

Low level laser therapy is used as a treatment of several conditions, including inflammatory processes and wound healing. Possible changes in mechanical properties of cells, caused by illumination, are investigated with optical magnetic twisting cytometry (OMTC), which is a technique used to evaluate mechanical properties in cell culture. Ferromagnetic micro beads are bound to cell cytoskeleton, the beads are magnetized vertically and a horizontal twisting magnetic field is applied causing a torque that moves the beads and deforms the cell, the beads rotate and displace. Based on the lateral displacement of the beads, elastic shear and loss moduli are obtained. Samples of human bronchial epithelial cell culture were divided in two groups: one was illuminated with a 660 nm red laser, 30 mW power, 0.75 W/cm2 irradiance, during different time intervals, and the other one, the control group, was not illuminated. The values of the mechanical constants of the cells of the control group showed a tendency of increasing with the time out of the incubator. On the other hand, the illuminated group showed constancy on the behavior of both moduli, keeping the normal conditions of the cell culture. Those results indicate that illumination can induce cells to homeostasis, and OMTC is sensitive to observe departures from the steady conditions. Hence, OMTC is an important technique which can be used to aggregate knowledge on the light effect in cell cytoskeleton and even on the low level laser therapy mechanisms in inflammatory processes and/or wound healing.