Lead-210 and polonium-210 concentrations in some species of marine molluscs.

Data are presented for 210Pb and 210Po concentrations in three species of molluscs collected in the intertidal region of the coast of Rio de Janeiro, Brazil. Lead-210 activity in the soft tissue of the edible mussel Perna perna was 20 times higher than that found in its shell. The visceral mass contained the largest activity for both radionuclides, which is attributed to the feeding habits of the molluscs. Animals collected from Ponta Negra beach (open sea) showed higher concentrations of isotopes than those collected from Boa Viagem beach (within Guanabara Bay).     

Effect of thiol reagents on functional properties and heme oxidation in the hemoglobin of Geochelone carbonaria

The reaction of thiol reagents with G. carbonaria hemoglobin was studied, and the oxygen equilibrium and kinetic of oxidation of derivatives determined. The oxygen affinity and kinetic of oxidation of hemoglobin derivatives were modified to various extents depending on the nature of thiol reagents used. Diamide yielded approximately 80% polymeric hemoglobin, although the oxidation kinetic, and the functional properties, were practically invariant (T1/2 = 10.0 min.; P50 = 5.0 mm Hg at pH 7.4; alkaline Bohr effect = -0.64). Iodoacetamide did not modify the electrophoretic pattern significantly, although all the free SH groups of hemoglobin were alkylated. A P50 of 2.5 mmHg at pH 7.4 and the Bohr effect of -0.15 were obtained; the T1/2 of about 6.4 min. was shorter than that for un-modified Hb. Similar T1/2 were obtained for Hb treated with oxidized glutathione, which produced polymeric Hb and glutathionyl-Hb. The oxygen binding characteristics showed that both of Hb derivatives, glutathionyl-Hb and polymeric Hb, maintain the capacity to transport the gas.     

Examining region-based methods for land cover classification using stochastic distances

A recent alternative to standard pixel-based classification of remote-sensing data is region-based classification, which has proved to be particularly useful when analysing high-resolution imagery of complex environments, such as urban areas, or when addressing noisy data, such as synthetic aperture radar (SAR) images. First, following certain criteria, the imagery is decomposed into homogeneous regions, and then each region is classified into a class of interest. The usual method for region-based classification involves using stochastic distances, which measure the distances between the pixel distributions inside an unknown region and the representative distributions of each class. The class, which is at the minimum distance from the unknown region distribution, is assigned to the region and this procedure is termed stochastic minimum distance classification (SMDC). This study reports the use of methods derived from the original SMDC, Support Vector Machine (SVM), and graph theory, with the objective of identifying the most robust and accurate classification methods. The equivalent pixel-based versions of region-based analysed methods were included for comparison. A case study near the Tapajós National Forest, in Pará state, Brazil, was investigated using ALOS PALSAR data. This study showed that methods based on the nearest neighbour, derived from SMDC, and SVM, with a specific kernel function, are more accurate and robust than the other analysed methods for region-based classification. Furthermore, pixel-based methods are not indicated to perform the classification of images with a strong presence of noise, such as SAR images.     

Quantum secure direct communication of digital and analog signals using continuum coherent states

In this work, we present optical schemes for secure direct quantum communication of digital and analog signals using continuum coherent states and frequency-dependent phase modulation. The main advantages of the proposed schemes are that they do not use entangled states and they can be implemented with today technology. The theory of quantum interference of continuum coherent state is described, and the optical setups for secure direct communication are presented and their securities are discussed.

     

Polarization microscopy as a tool for quantitative evaluation of collagen using picrosirius red in different stages of CKD in cats

Chronic kidney disease (CKD) is a relevant disease in feline clinic. The tubulointerstitial damage, with collagen deposition and fibrosis, is an important result of this process. The aim of this study was to quantify and correlate the deposition of collagen and severity of interstitial fibrosis (IF) in the kidney from cats in different stages of CKD. Kidney fragments from 10 adult cats with CKD were analyzed and stained by Masson's trichrome (MT) and Picrosirius red (PSR) for circular polarized microscopy. Random quantitative analysis was performed on MT sections to classify the degree of IF, per field area, with and without circular polarization. Statistics correlations were performed by Spearman's (ρ; p < .05). There was a significant correlation of IF quantification with the area of interstitial collagen deposition by polarized PSR (PSRp) (r = .7939, p = .0098) and nonpolarized PSR (PSRn) (r = .7781, p = .0080). There was a positive correlation of serum creatinine (sCr) at different stages of CKD with PSRp (r = .7939, p = .0098), PSRn (r = .8667, p = .0027) and MT (r = .7818, p = .0117). Correlations between the percentage of quantified area was also positive from PSRp to PSRn (r = .9030, p = .0009) and PSRp to MT (r = .7939, p = .0098). The PSRN was also correlated with MT (r = .9273, p = .0001). The correlation with IF and sCr follows the disease evolution and the quantification of collagen by PSR is an excellent tool for analyzing the disease severity at different stages.