All optical switches based on the coupling of surface plasmon polaritons

We studied the potentials of All Optical Switches (AOS) based on the intensity-dependent coupling and decoupling of light into the SPP modes (Surface Plasmon Polaritons) of a sinusoidally corrugated thin metal film (TMF), due to Kerr induced refractive index changes of the surrounding dielectrics. The ideal device has two spatially separated outputs, collecting the reflected and transmitted light and the active volume can be as small as 10(-2) mm(3). Gold and PTS (poly-(2,4-hexadiyne-1,6-diol bis(p-toluene sulfonate) are the materials considered. Losses are limited to 1.5 dB,while a 20 dB extinction ratio per gate has been theoretically demonstrated with signal pulsewidths of 5-10 ps , using a maximum optical switching peak power of 11 kW

Tandem chemiluminescence-flow injection analysis for dimethoate determination

This work was supported by the Ministry of Education and Science of Spain (Project CTM2006-11991) and FEDER funds.Catalá Icardo, M.; López Paz, JL.; Choves Barón, C. (2010). Tandem chemiluminescence-flow injection analysis for dimethoate determination. Luminescence. 25:235-236. https://doi.org/10.1002/bio.1217S2352362

Diversidad catabólica de un suelo crónicamente contaminado con hidrocarburos policíclicos aromáticos (PAHs) post estrés acido

El conocimiento del rol de los organismos indígenas en suelos contaminados es esencial para el desarrollo y aplicación de tecnologías de biorremediación exitosas. Las zonas petroquímicas de la provincia de Buenos Aires son un buen ejemplo de suelos expuestos crónicamente a hidrocarburos. Existen diferentes opiniones sobre si la contaminación con hidrocarburos reduce la diversidad microbiana conllevando a la perdida de resiliencia de las comunidades microbianas del suelo. Muchos microorganismos del suelo presentan tasas de respiración bajas, que pueden incrementarse al ser estimulados con sustratos fácilmente asimilables. Algunos autores sostienen que la respiración inducida por sustrato (SIR) es proporcional al tamaño original de la biomasa microbiana del suelo. SIR permite evaluar la diversidad catabólica del suelo estableciendo un perfil fisiológico de la comunidad. La diferencia con la técnica de Biolog radica en que en la primera el sustrato es adicionado directamente en el suelo evitando así los problemas que representan la inoculación de microorganismos de suelo en un medio semi-solido

Composting and biostimulation as strategies for chronically hydrocarbon contaminated soil recovering

The concept of treating PAH-contaminated soil by means of co-composting with organic materials or by mixing soil with mature compost has proved to be effective in the degradation of PAHs at the laboratory and/or field-scales. A contaminated soil was collected from a petrochemical area, near La Plata. It was characterized by a very low biological activity, probably due to the hydrocarbon content (4000ppm of aliphatic and 300ppm of PAH). The microbial populations were similar to those determined in pristine soils near of the area. The goals of our study were to investigate the potential of composting related practices in the biological recovery of the contaminated soil. Composting treatment (CT). A sample of soil was treated with amendment in ratio 0,7:0,3 (w/w) and the resulting material was mixed with bulking agent. It was incubated at room temperature in reactors of 34L during 4 months. The moisture was adjusted to 45%. Biostimulation treatment (BT). A sample of soil was mixed with compost (prepared 30 days before use) in ratio 0,7:0,3 (w/w) and it was incubated during 1 month at 25°C. This experiment was carried out in triplicate trays. The moisture was adjusted to 45%. Control reactors (S). Contaminated soil microcosm with any additive was used as control system. Microbial population densities. Viable heterotrophic bacterial count was performed using R2-Agar. The value for CT was higher than for S whereas the BT did not show differences with S. Fungi were enumerated on Rose Bengal Agar. For both treatments the counts were higher than for S. Phosphorus solubilising bacteria was enumerated on PIM media: the count in CT was higher than in S while BT did not show any difference. The most probable number of aromatic hydrocarbon-degrading bacteria was determined using mineral salts medium with the addition of a mix of PAHs. No differences were detected after both treatments in the hydrocarbon degrading bacteria counts. Biological Activity. Dehydrogenase assays were performed using soluble tetrazolium salt as an artificial acceptor. Both treatments produced significant increase in the dehydrogenase activity that was higher than those determined in S, during all the incubation time. Toxicity assays. Seed germination test using Lactuca Sativa was performed on water extracts. Only the CT increased significantly the germination. Hydrocarbons concentrations. The extracts were analyzed by GC-FID. No significant decrease was detected after 1 and 4 months respectively. Molecular analysis. PCR-DGGE analysis was performed. Both treatments produced a significant diversity increase of the populations. A successful composting treatment was evidenced by the visible changes in the matrix aspect in the CT treatment, in agreement with the higher bacterial counts, biological activity and percentage of seed germination. Although this treatment did not reduce significantly the hydrocarbon concentration, it was able to improve the soil quality in the experiment time

Remediation of a hydrocarbon chronically contaminated soil by combination of persulfate oxidation and bioremediation

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds in the environment generated by natural and anthropogenic activities. Because their hydrophobicity and low water solubility they are highly persistent in soil. Although the use of chemical oxidants can overcome the limitations of bioremediation, it is known that it damages the community and soil structures. We studied the effect of combined technologies, chemical oxidation followed by bioremediation, on chronically hydrocarbon contaminated soil. A chronically contaminated soil (S0) with 214 ppm of PAHs was treated with ammonium persulfate (PS) (3.3 g PS/ kg dry soil), OxS. Microcosms of oxidized soil were incubated (25°C, 25% moisture content), for 1 year as bioremediation process, BOxS. Soil microcosms without oxidation were used as bioremediation control, BS. The PAH concentration, PAH bioavailability (%), dissolved total carbon (% DTC), absorption and fluorescence of organic matter (OM), total nitrogen (N), sulphate (SO42-), phosphorous (P) and bacterial diversity were analysed. Hill’s numbers were used as diversity measures. The results were analysed using methods from the multivariate statistic. The PS application produced 30% of PAHs elimination and an increase of DTC and PAH bioavailability. The aqueous extract fluorescence attributed to the organic matter was higher than S0, but the relative emission from PAHs was lower. The corresponding spectroscopic analysis (E4/E6) did not show changes. Before the oxidation, S0 showed a very high diversity being an equal community. A dramatic decline in the richness was observed after PS oxidation. The OxS community showed an uneven assemblage with a few dominant species. The Actinomycetales (57%) and Bacillales (20%) were the predominant orders. By analysis of 16SrDNA hypervariable region, we found successional changes in the community along the treatment. The low richness and uneven assemblage remained until the fifth month but with Pseudomonadales as predominant order (71%). Slowly, the bioremediation allowed that the diversity was recovery (BOxS); despite of the richness was still low in compare with S0. At the end of the treatment, 47.5% of total PHA elimination was observed, leaving a lower DTC value in BOxS. The fluorescence intensity from OM was similar to S0 but principally as consequence of humic-like substances contribution, suggesting that the bacterial successional changes were principally to expenses of the available compound from the oxidized OM. The increment on P also suggested the effective bacterial involvement in the soil P cycle. The significantly higher SO42- concentration seemed to no exert much effect on the soil bacterial diversity. The bioremediation in BS after one year also showed a low richness. Although a reduced fluorescence was detected in this microcosms, the relative PAH and OM fluorescence contribution did not change. The coupled technology studied was suitable for elimination of PAHs with the recovery of microbial diversity associated to the metabolism of oxidized OM. The multifaceted approach were useful for understanding the global process in a chronical-contaminated soil

Effect of organic amendment on chronically hydrocarbon contaminated soil after chemical remediation

Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic organic pollutants persistent in soil. The remediation using chemical oxidants could overcome the limitations of bioremediation in the PAHs elimination, although it could also damage the community and the soil structure. The aim of this work was to evaluate the early effect of a combined strategy applied to chronically PAHs-contaminated soil. Chronically contaminated soil, S0 (214 ppm of PAHs), was treated with 3.3 g of ammonium persulfate, OxS0. Bioremediation treatments, BS and BOxS, were carried out in microcosms containing 500 g of S0 or OxS0 respectively, keeping constant the humidity and temperature. The stimulation treatments in SS and SOxS microcosms were done adding mature compost in S0 and OxS0 respectively. All microcosms were incubated 1 month at 25°C.The oxidative treatment produced an elimination of 29% of the total PAHs, and an additional PAHs elimination were detected from SOxS microcosms. The amendment allowed the microbial population recover and the dehydrogenase increase in SOxS microcosms in comparison with S0, after the first week. However, the increase was minor than that detected in SS microcosms. Both, the persulfate treatment and compost addition increased the toxicity of the aqueous extracts. The combined treatment in SOxS allowed the diversity indexes of the bacterial community were recovered after a month. Members of Sphingomonadales, Actinomycetales, Acidobacteria Gp6 and Rizobiales orders were predominant, suggesting the active metabolism of organic matter, nutrients mobilization and hydrocarbons degradation. A longer term treatment could define the potentiality of the combined strategy for the elimination of PAH

Microbiological diversity and functionality of a chronically hydrocarbon Contaminated soil post chemistry oxidation

In situ chemical oxidation (ISCO) is increasingly used for the remediation of soil containing organic contaminants such as polycyclic aromatic hydrocarbons (PAH). However, the impact on the soil microbial community has not been thoroughly elucidated. The aim of the study was to analyze the effect of the ammonium persulfate application followed by a bioremediation process on the matrix, microbial community and the PAH removal of the soil. Chronically contaminated soil (S) was collected from a petrochemical area (214 ppm PAH). Ammonium persulfate (PS) was sprayed as aqueous solution on contaminated soil by three additions (1% wt/wt) every two days and incubated at 30°C ( SOx). S and SOxwere further incubated at 25°C, 25% moisture content, mixed and monitored for 28 days. These microcosms were named SB and SOxB respectively. The PAH concentrations were determined by GC-FID. No PAH elimination was detected in SB. A significant elimination (35%) was observed in SOx while no additional decrease was detected SOxB. Alkaline extraction was performed to obtain an aqueous solution of natural organic matter of the soil. The Total Organic Carbon contents (TOC, TOC-5000 Shimadzu) and the Fluorescence Excitation Emission Matrixes (FEEM, Perkin-Elmer LS-50B) were determined for Sand SOx. FEEM of Spresents two zones of emission. The zone on lexc ~ 320 nm and lem ~ 440 nm could be assigned to the presence of PAH. These emissions were absent in SOx in line with the PAH elimination, and a significant increment on TOC values was also detected. A significant decrease in the microbial counts was observed in SOx. The subsequent bioremediation only increased the heterotrophic bacterial population which suggested that the available organic carbon allowed the growth of this population. To evaluate the microbial activity, four enzymes lipase, aril sulphatase, urease and protease were analyzed. All of them were slightly expressed in S microcosms and only lipase activity was significantly increased in SOx. Seed germination test using Lactuca Sativa on water extracts was performed to evaluate the soil toxicity. The toxicity detected in S was exacerbated in SOx and it was not reversed in SOxB. The dynamics of the bacterial community structure, analyzed by 16S rRNA PCR DGGE, evidenced a great change due to the oxidation. The clustering among the S and SOxB profile bands suggested the tendency of SOxB to recover the original structure. The pyrosequence analysis showed that members of actinobacteria, bacilli and acidimicrobiia classes were the predominant populations in SOx. Members of the actinobacteria became the dominant population in SOxB. This group was considered as k-strategist microorganisms and a major component in the later stages of successions in bioremediated soils. The initial PAH elimination provoked by PS was not followed by an additional elimination under bioremediation condition. However, a microbial succession of generalist populations was observe

Weekly paclitaxel as first-line chemotherapy in elderly advanced breast cancer patients: a phase II study of the Gruppo Italiano di Oncologia Geriatrica (GIOGer)

Background: First-line chemotherapy regimens suitable for elderly advanced breast cancer patients are still not defined. Patients and methods: Women with stage III or IV breast cancer aged >_70 years were enrolled in a phase II study aimed to evaluate both activity and toxicity of weekly paclitaxel. Among 46 planned patients, at least 18 responses and not more than seven unacceptable toxic events are required for a favourable conclusion. Paclitaxel 80 mg/m2 was administered weekly for 3 weeks every 28 days. Results: Unacceptable toxicity occurred in seven out of 46 patients evaluated for toxicity [15.2%; exact 95% confidence interval (CI) 7.6% to 28.2%] and was represented by one case of febrile neutropenia, one case of severe allergic reaction and five cases of cardiac toxicity. Among 41 patients evaluated for response, a complete response occurred in two (4.9%) patients and a partial response in 20 (48.8%), with an overall response rate of 53.7% (exact 95% CI 38.7% to 67.9%). The median progression-free survival was 9.7 months (95% CI 8.5\u201318.7) and median survival was 35.8 months (95% CI 19\u2013not defined). Conclusions: Weekly paclitaxel is highly active in elderly advanced breast cancer patients. Data on cardiovascular complications, however, indicate the need for a careful monitoring of cardiac function before and during chemotherap