Chlorophyll a fluorescence in Annona emarginata (Schltdl.) H. Rainer plants subjected to water stress and after rehydration

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Study of final-state radiation in decays of Z bosons produced in pp collisions at 7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for decays of stopped long-lived particles produced in proton-proton collisions at root s=8TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Chlorophyll fluorescence in guanandi tree (calophyllum brasiliense) after herbicide application

Chlorophyll fluorescence is currently used as a rapid diagnostic and nondestructive method to detect and quantify damage on the photosynthetic apparatus of leaves on weeds, crops and ornamental/coniferous trees in response to both environmental stress and herbicides. This study aimed to evaluate chlorophyll fluorescence in guanandi plants (Calophyllum brasiliense) after application of different postemergence herbicides. The experiment was performed in a completely randomized design, with six treatments (control, bentazon, sulfentrazone, isoxaflutole, atrazine and glyphosate) and five replications. The herbicide treatments were applied with a stationary sprayer, and electron transport rate (ETR) was subsequently analyzed with OS5p Multi-Mode Chlorophyll Fluorometer. In the monitored period, guanandi plants subjected to atrazine showed higher sensitivity to chlorophyll fluorescence than the other treatments. Although bentazon is a photosystem II inhibitor, it showed no major changes in electron transport for the studied species and in the monitored period. In summary, ETR is a good parameter to evaluate the effect of some herbicides on Calophyllum brasiliense plants.

Bell inequalities for K-0(K)over-bar(0) pairs from Phi-resonance decays

We analyze the premises of recent propositions to test local realism via the Bell inequalities using neutral kaons from φ resonance decays as entangled Einstein-Podolsky-Rosen pairs. We pay special attention to the derivation of the Bell inequalities, or related expressions, for unstable and oscillating kaon quasispin states and to the possibility of the actual identification of these states through their associated decay modes. We discuss an indirect method to extract probabilities to find these states by combining experimental information with theoretical input. However, we still find inconsistencies in previous derivations of the Bell inequalities. We show that the identification of the quasispin states via their associated decay mode does not allow the free choice to perform different tests on them, a property which is crucial to establish the validity of any Bell inequality in the context of local realism. In view of this we propose a different kind of Bell inequality in which the free choice or adjustability of the experimental setup is guaranteed. We also show that the proposed inequalities are violated by quantum mechanics. ©1999 The American Physical Society.

Frequency upconversion involving triads and quartets of ions in a Pr3+/Nd3+ codoped fluoroindate glass

Frequency upconversion (UC) processes involving energy transfer (ET) among Nd 3+ and Pr 3+ ions in a fluoroindate glass are reported. In a first experiment, the excitation of Pr 3+ [transition 3H 4→ 1D 2] and of Nd 3+ [transition 4I 9/2→( 2G 7/2+ 4G 5/2)] was achieved with a dye laser operating in the 575-590 nm range. In a second experiment, the Nd 3+ ions were excited with the second harmonic of a Nd: YAG laser at 532 nm. The ET processes leading to UC in both experiments were studied by monitoring the blue fluorescence decay at 480 nm due to the transition 3P 0→ 3H 4 in Pr 3+. In the more relevant UC process, quartets of ions (Nd-Nd-Pr-Pr) are excited due to absorption of three laser photons by two Nd 3+ ions which transfer their energy to two Pr 3+ ions. Each Pr 3+ ion promoted to the 3P 0 level decays to the ground state emitting one photon in the blue region. This conclusion was achieved investigating the dependence of the UC fluorescence intensity as a function of laser intensity, samples concentrations, and temporal behavior of the UC signal. Other UC processes involving nonisoionic groups of three ions are also reported. © 2002 American Institute of Physics.

Anomalous couplings of the third generation in rare B decays

We study the potential effects of anomalous couplings of the third generation quarks to gauge bosons in rare B decays. We focus on the constraints from flavor changing neutral current processes such as b→sγ and b →sl+l-. We consider both dimension-four and dimension-five operators and show that the latter can give large deviations from the standard model in the still unobserved dilepton modes, even after the bounds from b→sγ and precision electroweak observables are taken into account. ©2000 The American Physical Society.

Effects of dental bleaching on the color, translucency and fluorescence properties of enamel and dentin

The objective of this study was to evaluate the color, translucency and fluorescence of bovine enamel and dentin submitted to different bleaching modalities. Pairs of enamel and dentin discs (3 mm in diameter) were obtained from 150 bovine teeth. In 75 of the pairs, one specimen had the enamel removed (Dentin Group). The dentin was removed from one specimen of the remaining 75 pairs (Enamel Group) and the other specimen was left unaltered (Enamel + Dentin). The evaluation of color, translucency and fluorescence was performed with a spectrophotometer using the CIE L* a* b*. Each group was subdivided into three subgroups: Control, composed of specimens that were not bleached, and two experimental subgroups, bleached with either 10% carbamide peroxide (CP10%) or 35% hydrogen peroxide (HP35%). The CP10% bleaching gel was applied 2 h/day for 14 days. The HP35% bleaching agent was applied using two applications of 30 min each, with a one week interval between each application. When not being bleached, the specimens were immersed in artificial saliva. The color, translucency and fluorescence ratings were assessed using spectrophotometry 7 days after the treatment. Regarding color, significant differences were found between bleaching techniques in the groups Enamel and Enamel + Dentin, with a higher color difference for HP35%. Bleaching did not change the translucency of the dental tissues. There were significant differences for fluorescence for the HP35% subgroups of Dentin and Enamel + Dentin, and for the CP10% subgroup of Enamel. Dental bleaching changed the color and fluorescence of the dental tissues, however translucency was not affected.

Trace elements as tumor biomarkers and prognostic factors in breast cancer: a study through energy dispersive x-ray fluorescence

Background The application and better understanding of traditional and new breast tumor biomarkers and prognostic factors are increasing due to the fact that they are able to identify individuals at high risk of breast cancer, who may benefit from preventive interventions. Also, biomarkers can make possible for physicians to design an individualized treatment for each patient. Previous studies showed that trace elements (TEs) determined by X-Ray Fluorescence (XRF) techniques are found in significantly higher concentrations in neoplastic breast tissues (malignant and benign) when compared with normal tissues. The aim of this work was to evaluate the potential of TEs, determined by the use of the Energy Dispersive X-Ray Fluorescence (EDXRF) technique, as biomarkers and prognostic factors in breast cancer. Methods By using EDXRF, we determined Ca, Fe, Cu, and Zn trace elements concentrations in 106 samples of normal and breast cancer tissues. Cut-off values for each TE were determined through Receiver Operating Characteristic (ROC) analysis from the TEs distributions. These values were used to set the positive or negative expression. This expression was subsequently correlated with clinical prognostic factors through Fisher’s exact test and chi-square test. Kaplan Meier survival curves were also evaluated to assess the effect of the expression of TEs in the overall patient survival. Results Concentrations of TEs are higher in neoplastic tissues (malignant and benign) when compared with normal tissues. Results from ROC analysis showed that TEs can be considered a tumor biomarker because, after establishing a cut-off value, it was possible to classify different tissues as normal or neoplastic, as well as different types of cancer. The expression of TEs was found statistically correlated with age and menstrual status. The survival curves estimated by the Kaplan-Meier method showed that patients with positive expression for Cu presented a poor overall survival (p < 0.001). Conclusions This study suggests that TEs expression has a great potential of application as a tumor biomarker, once it was revealed to be an effective tool to distinguish different types of breast tissues and to identify the difference between malignant and benign tumors. The expressions of all TEs were found statistically correlated with well-known prognostic factors for breast cancer. The element copper also showed statistical correlation with overall survival.

Pharmacokinetics of Photogem Using Fluorescence Spectroscopy in Dimethylhydrazine-Induced Murine Colorectal Carcinoma

This study aimed to investigate the pharmacokinetics of a hematoporphyrin derivative in colonic tumors induced by dimethylhydrazine and adjacent normal colon in Wistar rats using an in vivo fluorescence spectroscopy technique. In conventional clinical application of photodynamic therapy, the interval between photosensitizer (PS) administration and lesion illumination is often standardized without taking into account variations due to the type or localization of the tumor and intrinsic differences in the microcirculation and vascular permeability of each target organ. The analysis of the fluorescence spectra was based on the intensity of porphyrin emission band centered at around 620nm in normal colon and colon tumors. The photosensitizer fluorescence intensity rapidly grew for carcinoma and normal colon, reaching the maximum values 1 and 3 hours after PS injection, respectively. Data presented here allow us to verify that the best compromise between selectivity and drug concentration for colon carcinoma in rats took place in the interval between 1 to 4 h after PS injection.

Radiographic and Laser Fluorescence Methods Have No Benefits for Detecting Caries in Primary Teeth

Clinical guidelines advise that dentists take radiographs in children to detect caries lesions missed by visual inspection; however, due to the current low caries prevalence in most countries, we hypothesized that the adjunct methods of caries detection would not significantly improve the detection of primary molar lesions in comparison to visual inspection alone. We evaluated the performance of visual inspection, alone or in combination with radiographic and laser fluorescence pen (LFpen) methods, in detecting occlusal and approximal caries lesions in primary molars. Two examiners evaluated children who had sought dental treatment with these diagnostic strategies. The reference standard involved the temporary separation of approximal and operative interventions for occlusal surfaces. The sensitivity, specificity, accuracy and utility of diagnostic strategies were calculated. Simultaneous combined strategies increased sensitivities but decreased specificities. Furthermore, no differences were observed in accuracy and utility, parameters more influenced by caries prevalence. In conclusion, adjunct radiographic and laser fluorescence methods offer no benefits to the detection of caries in primary teeth in comparison to visual inspection alone; hence, present clinical guidelines should be re-evaluated. Copyright (C) 2012 S. Karger AG, Basel

Liquid Crystal Nanodispersions Enable the Cutaneous Delivery of Photosensitizer for Topical PDT: Fluorescence Microscopy Study of Skin Penetration

Topical photodynamic therapy (PDT) has been applied to almost all types of nonmelanoma skin cancer and numerous superficial benign skin disorders. Strategies to improve the accumulation of photosensitizer in the skin have been studied in recent years. Although the hydrophilic phthalocyanine zinc compound, zinc phthalocyanine tetrasulfonate (ZnPcSO4) has shown high photodynamic efficiency and reduced phototoxic side effects in the treatment of brain tumors and eye conditions, its use in topical skin treatment is currently limited by its poor skin penetration. In this study, nanodispersions of monoolein (MO)-based liquid crystalline phases were studied for their ability to increase ZnPcSO4 uptake by the skin. Lamellar, hexagonal and cubic crystalline phases were prepared and identified by polarizing light microscopy, and the nanodispersions were analyzed by dynamic light scattering. In vitro skin penetration studies were performed using a Franz's cell apparatus, and the skin uptake was evaluated in vivo in hairless mice. Aqueous dispersions of cubic and hexagonal phases showed particles of nanometer size, approximately 224 +/- 10 nm and 188 +/- 10 nm, respectively. In vitro skin retention experiments revealed higher fluorescence from the ZnPcSO4 in deeper skin layers when this photosensitizer was loaded in the hexagonal nanodispersion system when compared to both the cubic phase nanoparticles and the bulk crystalline phases (lamellar, cubic and hexagonal). The hexagonal nanodispersion showed a similar penetration behavior in animal tests. These results are important findings, suggesting the development of MO liquid crystal nanodispersions as potential delivery systems to enhance the efficacy of topical PDT.

Influence of dental materials used for sealing caries lesions on laser fluorescence measurements

The aim of this study was to determine the influence of thickness and aging on the intrinsic fluorescence of sealing materials and their ability to block fluorescence from the underlying surface as assessed using a laser fluorescence device. Cavities of 0.5 mm and 1 mm depth were drilled into acrylic boards which were placed over two surfaces with different fluorescence properties: a low-fluorescence surface, to assess the intrinsic fluorescence of the sealing materials, and a high-fluorescence surface, to assess the fluorescence-blocking ability of the sealing materials. Ten cavities of each depth were filled with different sealing materials: Adper Scotchbond Multi-Purpose, Adper Single Bond 2, FluroShield, Conseal f and UltraSeal XT Plus. Fluorescence was measured with a DIAGNOdent pen at five different time points: empty cavity, after polymerization, and 1 day, 1 week and 1 month after filling. The individual values after polymerization, as well as the area under the curve for the different periods were submitted to ANOVA and the Tukey test (p < 0.05). At 0.5 mm, Scotchbond, FluroShield and UltraSeal showed insignificant changes in intrinsic fluorescence with aging and lower fluorescence after polymerization than Single Bond and Conseal. At 1 mm, Scotchbond and FluroShield showed the lowest intrinsic fluorescence, but only Scotchbond showed no chagnes in fluorescence with aging. At both depths, Scotchbond blocked significantly less fluorescence. All sealing materials blocked more fluorescence when applied to a depth of 1 mm. At 0.5 mm, fissure sealants blocked more fluorescence than adhesives, and did not show significant changes with aging. Scotchbond had the least affect on the fluorescence from the underlying surface and would probably have the least affect on the monitoring of sealed dental caries by laser fluorescence.

Fluorescence polarization assay, competitive enzyme-linked immunosorbent assay (ELISA-C) and indirect ELISA for the diagnosis of brucellosis in buffaloes (Bubalus bubalis)

The objective of the present study was to compare the performance of three serological tests for diagnosis of Brucella abortus infections in buffaloes (Bubalus bubalis). Serum samples collected from 696 adult females were submitted to the competitive enzyme-linked immunosorbent assay (ELISAC), (I-ELISA), fluorescence polarization test (FPA), 2-mercaptoethanol test (2-ME) and complement fixation test (CFT). The gold standard was the combination of CFT and 2-ME, considering as positive the reactors in both CFT and 2-ME, and as negative those non-reactors. ROC analyses were done for C-ELISA, I-ELISA and FPA and the Kappa agreement index were also calculated. The best combinations of relative sensitivity (SEr) and relative specificity (SPr) and Kappa were given by C-ELISA (96.9%, 99.1%, and 0.932, respectively) and FPA (92.2%, 97.6 and 0.836, respectively). The C-ELISA and FPA were the most promising confirmatory tests for the serological diagnosis of brucellosis in buffaloes, and for these tests, cut-off values for buffaloes may be the same as those used for bovines.

Paper-based diffusive gradients in thin films technique coupled to energy dispersive X-ray fluorescence spectrometry for the determination of labile Mn, Co, Ni, Cu, Zn and Pb in river water

The diffusive gradients in thin films (DGT) technique has shown enormous potential for labile metal monitoring in fresh water due to the preconcentration, time-integrated, matrix interference removal and speciation analytical features. In this work, the coupling of energy dispersive X-ray fluorescence (EDXRF) with paper-based DGT devices was evaluated for the direct determination of Mn, Co. Ni, Cu, Zn and Pb in fresh water. The DGT samplers were assembled with cellulose (Whatman 3 MM chromatography paper) as the diffusion layer and a cellulose phosphate ion exchange membrane (Whatman P 81 paper) as the binding agent. The diffusion coefficients of the analytes on 3 MM chromatography paper were calculated by deploying the DGT samplers in synthetic solutions containing 500 mu g L-1 of Mn. Co, Ni, Cu, Zn and Pb (4 L at pH 5.5 and ionic strength at 0.05 mol L-1). After retrieval, the DGT units were disassembled and the P81 papers were dried and analysed by EDXRF directly. The 3 MM chromatographic paper diffusion coefficients of the analytes ranged from 1.67 to 1.87 x 10(-6) cm(2) s(-1). The metal retention and phosphate group homogeneities on the P81 membrane was studied by a spot analysis with a diameter of 1 mm. The proposed approach (DGT-EDXRF coupling) was applied to determine the analytes at five sampling sites (48 h in situ deployment) on the Piracicaba river basin, and the results (labile fraction) were compared with 0.45 mu m dissolved fractions determined by synchrotron radiation-excited total reflection X-ray fluorescence (SR-TXRF). The limits of detection of DGT-EDXRF coupling for the analytes (from 7.5 to 26 mu g L-1) were similar to those obtained by the sensitive SR-TXRF technique (3.8 to 9.1 mu g L-1). (C) 2012 Elsevier B.V. All rights reserved.