Estuarine and oceanic influences on copepod abundance and production of a subtropical coastal area

We investigated the influence of nutrient-rich oceanic waters in comparison to the estuarine outflow from Santos Bay (SE Brazil) on copepod abundance and production on the adjacent inner shelf. Zooplankton samples were collected with a Multinet in spring 2005 and in summer 2006. Copepod biomass was derived from length-weight regressions, and growth rates were estimated from empirical models. Altogether, 58 copepod taxa were identified. The highest abundances were due to small-sized organisms including nauplii, oncaeids and copepodids of paracalanids and clausocalanids. Biomass and secondary production mirrored copepod abundance, with Temora copepodids accompanying the above-mentioned taxa as major contributors. The contribution of naupliar biomass and production was low (2.2 and 3.8% of the total, respectively). The influence of the Santos Bay outflow was observed only in spring, when Coastal Water (CW) dominated at the study site; whereas in summer the inner shelf was occupied by CW in the surface layer and the oceanic South Atlantic Central Water (SACW) in the bottom layer. The SACW intrusion had more of an influence for the increase in copepod production than the Santos Bay plume. The distribution and dynamics of the oceanic water masses seemed to be the most important influence on copepod diversity and production at this subtropical site.

Production and characterization of poly-(3-hydroxybutyrate) from recombinant Escherichia coli grown on cheap renewable carbon substrates

Although the biopolymer poly-(3-hydroxybutyrate), P[3HB], presents physicochemical properties that make it an alternative material to conventional plastics, its biotechnological production is quite expensive. As carbon substrates contribute greatly to P[3HB] production cost, the utilization of a cheaper carbon substrate and less demanding micro-organisms should decrease its cost. In the present study a 23 factorial experimental design was applied, aiming to evaluate the effects of using hydrolysed corn starch (HCS) and soybean oil (SBO) as carbon substrates, and cheese whey (CW) supplementation in the mineral medium (MM) on the responses, cell dried weigh (DCW), percentage P[3HB] and mass P[3HB] by recombinant Escherichia coli strains JM101 and DH10B, containing the P[3HB] synthase genes from Cupriavidus necator (ex-Ralstonia eutropha). The analysis of effects indicated that the substrates and the supplement and their interactions had positive effect on CDW. Statistically generated equations showed that, at the highest concentrations of HCS, SO and CW, theoretically it should be possible to produce about 2 g L(1) DCW, accumulating 50% P[3HB], in both strains. To complement this study, the strain that presented the best results was cultivated in MM added to HCS, SBO and CW ( in best composition observed) and complex medium (CM) to compare the obtained P[3HB] in terms of physicochemical parameters. The obtained results showed that the P[3HB] production in MM (1.29 g L(-1)) was approximately 20% lower than in CM (1.63 g L(-1)); however, this difference can be compensated by the lower cost of the MM achieved by the use of cheap renewable carbon sources. Moreover, using differential scanning calorimetry and thermogravimetry analyses, it was observed that the polymer produced in MM was the one which presented physicochemical properties (Tg and Tf) that were more similar to those found in the literature for P[3HB].

Color tunability of intense upconversion emission from Er3+-Yb3+ co-doped SiO2-Ta2O5 glass ceramic planar waveguides

This work reports on the infrared-to-visible CW frequency upconversion from planar waveguides based on Er3+-Yb3+-doped 100-xSiO(2)-xTa(2)O(5) obtained by a sol-gel process and deposited onto a SiO2-Si substrate by dip-coating. Surface morphology and optical parameters of the planar waveguides were analyzed by atomic force microscopy and the m-line technique. The influence of the composition on the electronic properties of the glass-ceramic films was followed by the band gap ranging from 4.35 to 4.51 eV upon modification of the Ta2O5 content. Intense green and red emissions were detected from the upconversion process for all the samples after excitation at 980 nm. The relative intensities of the emission bands around 550 nm and 665 nm, assigned to the H-2(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2), and F-4(9/2) -> I-4(15/2) transitions, depended on the tantalum oxide content and the power of the laser source at 980 nm. The upconversion dynamics were investigated as a function of the Ta2O5 content and the number of photons involved in each emission process. Based on the upconversion emission spectra and 1931CIE chromaticity diagram, it is shown that color can be tailored by composition and pump power. The glass ceramic films are attractive materials for application in upconversion lasers and near infrared-to-visible upconverters in solar cells.

Frequency upconversion properties of Tm3+ doped TeO2-ZnO glasses containing silver nanoparticles

Frequency upconversion (UC) properties of Tm3+ doped TeO2-ZnO glasses containing silver nanoparticles (NPs) were investigated. Infrared-to-visible and infrared-to-infrared UC processes associated to the Tm3+ ions were studied by exciting the samples with a cw 1050 nm ytterbium laser. The luminescence intensity as a function of laser intensity was also measured using a pulsed 1047 nm Nd3+:YVO laser in order to determine the number of photons participating in the UC processes. Enhancement of the UC signals for samples heat-treated during various time intervals is attributed to the growth of the local field in the vicinity of the NPs. PL enhancement by one-order of magnitude was observed in the whole spectrum of the samples heat-treated during 48 h. On the other hand PL quenching was observed for the samples heat-treated more than 48 h. (c) 2011 Elsevier B.V. All rights reserved.

Spatial-temporal variation of Paralonchurus brasiliensis (Actinopterygii: Sciaenidae) density in relation to some environmental factors on the inner shelf of south-eastern Brazilian coast

The temporal and spatial variation of Paralonchurus brasiliensis density (fish per m(2)) in relation to environmental factors was studied on the coasts of Ubatuba and Caraguatatuba, south-eastern Brazil. The fish were collected by shrimp fishery trawl on a monthly basis from January to December, 2002. Seven depths were previously established and for each one the temperature, salinity, organic matter content and grain size of the sediment (phi) was measured. The seasonal analysis of temperature and salinity indicated the presence of the water masses South Atlantic Central Water (SACW) and Coastal Waters (CW) acting in the study area. A total of 29,808 fish were collected during the study period. The highest densities were registered during the summer and autumn indicating an association with CW. The fish population moved to shallow depths during the intrusion of the cold water mass, SACW. The highest densities were registered in depths where the sediment composition ranged from fine sand to silt-clay. Thus, the temperature and type of the sediment are the main environmental factors which affect the spatial-temporal variation of P. brasiliensis density in south-eastern Brazil.

Deconvolution of the EPR spectra of vanadium oxide nanotubes

In this work we report results of continuous wave (CW) electron paramagnetic resonance (EPR) spectroscopy of vanadium oxide nanotubes. The observed EPR spectra are composed of a weak well-resolved spectrum of isolated V4+ ions on top of an intense and broad structure-less line shape, attributed to spin-spin exchanged V4+ clusters. With the purpose to deconvolute the structured weak spectrum from the composed broad line, a new approach based on the Krylov basis diagonalization method (KBDM) is introduced. It is based on the discrimination between broad and sharp components with respect to a selectable threshold and can be executed with few adjustable parameters, without the need of a priori information on the shape and structure of the lines. This makes the method advantageous with respect to other procedures and suitable for fast and routine spectral analysis, which, in conjunction with simulation techniques based on the spin Hamiltonian parameters, can provide a full characterization of the EPR spectrum. Results demonstrate and characterize the coexistence of two V4+ species in the nanotubes and show good progress toward the goal of obtaining high fidelity deconvoluted spectra from complex signals with overlapping broader line shapes. (C) 2012 Elsevier Inc. All rights reserved.

Continuous-wave watt-level Nd:YLF/KGW Raman laser operating at near-IR, yellow and lime-green wavelengths

A Nd:YLF/KGW Raman laser has been investigated in this work. We have demonstrated CW output powers at six different wavelengths, 1147 nm (0.70 W), 1163 nm (0.95 W), 549 nm (0.65 W), 552 nm (1.90 W), 573 nm (0.60 W) and 581 nm (1.10 W), with higher peak powers achieved under quasi-CW operation. Raman conversion of the 1053 nm fundamental emission is reported for the first time, enabling two new wavelengths in crystalline Raman lasers, 549 nm and 552 nm. The weak thermal lensing associated with Nd:YLF has enabled to achieve good beam quality, M-2 <= 2.0, and stable operation in relatively long cavities. (C) 2012 Optical Society of America

Photodynamic antimicrobial chemotherapy (PACT) using phenothiazine derivatives as photosensitizers against Leishmania braziliensis

Background and Objective Cutaneous and mucocutaneous leishmaniasis are diseases characterized by skin or mucosal manifestations. In the new world, Leishmania braziliensis is the main etiological agent of cutaneous leishmaniasis, condition that may evolve to the mucocutaneous form. The therapeutic arsenal routinely employed to treat infected patients is unsatisfactory, especially for pentavalent antimonials, treatment recommended by the WHO, as they are often highly toxic, poorly tolerated and of variable effectiveness. This work aimed to evaluate in vitro the effectiveness of photodynamic antimicrobial chemotherapy as a new approach for the treatment of leishmaniasis. Materials and Methods A laser (??=?660?nm, 40?mW, 4.2?J/cm2, and 8.4?J/cm2, CW) associated to phenothiazine's derivatives (5 and 10?mu g/ml, toluidine blue O, methylene blue, or phenothiazine) on the promastigote forms of L. braziliensis in a single session. Samples were removed and analyzed in a hemocytometer 72?hours after PACT and viability of the parasites was assessed in quadruplicates. Results An important decrease in the number of viable parasites on all treated groups in comparison to their controls was observed as all tested compounds lead to significant parasite lethality being the highest lethality achieved with 10?mu g/ml of TBO. No lethality was observed on groups treated with laser or with any of the compounds separately. Conclusions TBO presented higher parasite lethality in comparison to MB with impressive reduction from 1?hour to 5?minutes of pre-incubation time. Lasers Surg. Med. 44: 850855, 2012. (c) 2012 Wiley Periodicals, Inc.

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.

Caspase-mediated cleavage of the exosome subunit PM/Scl-75 during apoptosis

Recent studies have implicated the dying cell as a potential reservoir of modified autoantigens that might initiate and drive systemic autoimmunity in susceptible hosts. A number of subunits of the exosome, a complex of 3'→5' exoribonucleases that functions in a variety of cellular processes, are recognized by the so-called anti-PM/Scl autoantibodies, found predominantly in patients suffering from an overlap syndrome of myositis and scleroderma. Here we show that one of these subunits, PM/Scl-75, is cleaved during apoptosis. PM/Scl-75 cleavage is inhibited by several different caspase inhibitors. The analysis of PM/Scl-75 cleavage by recombinant caspase proteins shows that PM/Scl-75 is efficiently cleaved by caspase-1, to a smaller extent by caspase-8, and relatively inefficiently by caspase-3 and caspase-7. Cleavage of the PM/Scl-75 protein occurs in the C-terminal part of the protein at Asp369 (IILD369↓G), and at least a fraction of the resulting N-terminal fragments of PM/Scl-75 remains associated with the exosome. Finally, the implications of PM/Scl-75 cleavage for exosome function and the generation of anti-PM/Scl-75 autoantibodies are discussed.

Necrosis response to photodynamic therapy using light pulses in the femtosecond regime

One of the clinical limitations of the photodynamic therapy (PDT) is the reduced light penetration into biological tissues. Pulsed lasers may present advantages concerning photodynamic response when compared to continuous wave (CW) lasers operating under the same average power conditions. The aim of this study was to investigate PDT-induced response when using femtosecond laser (FSL) and a first-generation photosensitizer (Photogem) to evaluate the induced depth of necrosis. The in vitro photodegradation of the sensitizer was monitored during illumination either with CWor an FSL as an indirect measurement of the PDT response. Healthy liver of Wistar rats was used to evaluate the tissue response. The photosensitizer was endovenously injected and 30 min after, an energy dose of 150 Jcm-2 was delivered to the liver surface. We observed that the photodegradation rate evaluated via fluorescence spectroscopy was higher for the FSL illumination. The FSL-PDT produced a necrosis nearly twice as deep when compared to the CW-PDT. An increase of the tissue temperature during the application was measured and was not higher than 2.5 °C for the CW laser and not higher than 4.5 °C for the pulsed laser. FSL should be considered as an alternative in PDT applications for improving the results in the treatment of bulky tumors where higher light penetration is required.

Effect of resonant tunneling on exciton dynamics in coupled dot-well nanostructures

Excitonic dynamics in a hybrid dot-well system composed of InAs quantum dots (QDs) and an InGaAs quantum well (QW) is studied by means of femtosecond pump-probe reflection and continuous wave (cw) photoluminescence (PL) spectroscopy. The system is engineered to bring the QW ground exciton state into resonance with the third QD excited state. The resonant tunneling rate is varied by changing the effective barrier thickness between the QD and QW layers. This strongly affects the exciton dynamics in these hybrid structures as compared to isolated QW or QD systems. Optically measured decay times of the coupled system demonstrate dramatically different response to temperature change depending on the strength of the resonant tunneling or coupling strength. This reflects a competition between purely quantum mechanical and thermodynamical processes.