Light-Induced Oxidation of Unsaturated Lipids as Sensitized by Flavins

Triplet-excited riboflavin ((3)RF*) was found by laser flash photolysis to be quenched by polyunsaturated fatty acid methyl esters in tert-butanol/water (7:3, v/v) in a second-order reaction with k similar to 3.0 x 10(5) L mol(-1) s(-1) at 25 degrees C for methyl linoleate and 3.1 x 10(6) L mol(-1) s(-1), with Delta H double dagger = 22.6 kJ mol(-1) and Delta S double dagger = -62.3 J K(-1) mol(-1), for methyl linolenate in acetonitrile/water (8:2, v/v). For methyl oleate, k was <10(4) L mol(-1) s(-1). For comparison, beta-casein was found to have a rate constant k similar to 4.9 x 10(8) L mol(-1) s(-1). Singlet-excited flavin was not quenched by the esters as evidenced by insensitivity of steady-state fluorescence to their presence. Density functional theory (DFT) calculations showed that electron transfer from unsaturated fatty acid esters to triplet-excited flavins is endergonic, while a formal hydrogen atom transfer is exergonic (Delta G(HAT)degrees = -114.3, -151.2, and -151.2 kJ mol(-1) for oleate, linoleate, and linolenate, respectively, in acetonitrile). The reaction is driven by acidity of the lipid cation radical for which a pK(a) similar to -0.12 was estimated by DFT calculations. Absence of electrochemical activity in acetonitrile during cyclic voltammetry up to 2.0 V versus NHE confirmed that Delta G(ET)degrees > 0 for electron transfer. Interaction of methyl esters with (3)RF* is considered as initiation of the radical chain, which is subsequently propagated by combination reactions with residual oxygen. In this respect, carbon-centered and alkoxyl radicals were detected using the spin trapping technique in combination with electron paramagnetic resonance spectroscopy. Moreover, quenching of 3RF* yields, directly or indirectly, radical species which are capable of initiating oxidation in unsaturated fatty acid methyl esters. Still, deactivation of triplet-excited flavins by lipid derivatives was slower than by proteins (factor up to 10(4)), which react preferentially by electron transfer. Depending on the reaction environment in biological systems (including food), protein radicals are expected to interfere in the mechanism of light-induced lipid oxidation.

Photo-assisted electrochemical degradation of the commercial herbicide atrazine

This paper presents a degradation study of the pesticide atrazine using photo-assisted electrochemical methods at a dimensionally stable anode (DSA (R)) of nominal composition Ti/Ru(0.3)Ti(0.7)O(2) in a prototype reactor. The effects of current density, electrolyte flow-rate, as well as the use of different atrazine concentrations are reported. The results indicate that the energy consumption is substantially reduced for the combined photochemical and electrochemical processes when compared to the isolated systems. It is observed that complete atrazine removal is achieved at low current densities when using the combined method, thus reducing the energy required to operate the electrochemical system. The results also include the investigation of the phytotoxicity of the treated solutions.

Photo-assisted electrochemical degradation of real textile wastewater

In the present study, photo-assisted electrochemical degradation of real textile wastewater was performed. Degradation assays were performed at constant current (40 mA cm(-2)) in a combined electro/photochemical flow-cell using a Ti/Ru(0.3)Ti(0.7)O(2) DSA(R) type electrode. The results show that the method is capable of removing color and chemical oxygen demand (COD) from the effluent. Additionally, the effect of initial pH and type of supporting electrolyte (Na(2)SO(4) or NaCl) was investigated. The principal figures of merit used in this study were COD removal and color removal (605 nm). The results show that up to 72% color and up to 59% COD removal in 120 min is possible under the operating conditions employed. Studies of the phytotoxicity of the wastewater before and after the photo-assisted degradation assays are also presented and the results demonstrate that the toxicity of the effluent is dependent on the length of electrolysis time and the treatment procedure employed.

Dynamic whole system testing of combined renewable heating systems : the current state of the art

Objective: For the evaluation of the energetic performance of combined renewable heating systems that supply space heat and domestic hot water for single family houses, dynamic behaviour, component interactions, and control of the system play a crucial role and should be included in test methods. Methods: New dynamic whole system test methods were developed based on “hardware in the loop” concepts. Three similar approaches are described and their differences are discussed. The methods were applied for testing solar thermal systems in combination with fossil fuel boilers (heating oil and natural gas), biomass boilers, and/or heat pumps. Results: All three methods were able to show the performance of combined heating systems under transient operating conditions. The methods often detected unexpected behaviour of the tested system that cannot be detected based on steady state performance tests that are usually applied to single components. Conclusion: Further work will be needed to harmonize the different test methods in order to reach comparable results between the different laboratories. Practice implications: A harmonized approach for whole system tests may lead to new test standards and improve the accuracy of performance prediction as well as reduce the need for field tests.

Trips and their CO2 emissions induced by a shopping center

Most previous studies have focused on entire trips in a geographic region, while a few of them addressed trips induced by a city landmark. Therefore paper explores trips and their CO2 emissions induced by a shopping center from a time-space perspective and their usage in relocation planning. This is conducted by the means of a case study in the city of Borlänge in mid-Sweden where trips to the city’s largest shopping mall in its center are examined. We use GPS tracking data of car trips that end and start at the shopping center. Thereafter, (1) we analyze the traffic emission patterns from a time-space perspective where temporal patterns reveal an hourly-based traffic emission dynamics and where spatial patterns uncover a heterogeneous distribution of traffic emissions in spatial areas and individual street segments. Further, (2) this study reports that most of the observed trips follow an optimal route in terms of CO2 emissions. In this respect, (3) we evaluate how well placed the current shopping center is through a comparison with two competing locations. We conclude that the two suggested locations, which are close to the current shopping center, do not show a significant improvement in term of CO2 emissions.

The discourses on induced abortion in Ugandan daily newspapers : a discourse analysis

Background: Ugandan law prohibits abortion under all circumstances except where there is a risk for the woman's life. However, it has been estimated that over 250 000 illegal abortions are being performed in the country yearly. Many of these abortions are carried out under unsafe conditions, being one of the most common reasons behind the nearly 5000 maternal deaths per year in Uganda. Little research has been conducted in relation to societal views on abortion within the Ugandan society. This study aims to analyze the discourse on abortion as expressed in the two main daily Ugandan newspapers. Method: The conceptual content of 59 articles on abortion between years 2006-2012, from the two main daily English-speaking newspapers in Uganda, was studied using principles from critical discourse analysis. Results: A religious discourse and a human rights discourse, together with medical and legal sub discourses frame the subject of abortion in Uganda, with consequences for who is portrayed as a victim and who is to blame for abortions taking place. It shows the strong presence of the Catholic Church within the medial debate on abortion. The results also demonstrate the absence of medial statements related to abortion made by political stakeholders. Conclusions: The Catholic Church has a strong position within the Ugandan society and their stance on abortion tends to have great influence on the way other actors and their activities are presented within the media, as well as how stakeholders choose to convey their message, or choose not to publicly debate the issue in question at all. To decrease the number of maternal deaths, we highlight the need for a more inclusive and varied debate that problematizes the current situation, especially from a gender perspective.

Use of microprojectile bombardment in transient expression assays to analyze protochlorophyllide reductase gene expression in greening maize seedling leaf cells

In young cells of leaf meristems the progenitors of chloroplasts are small organelles known as proplastids, which divide and differentiate into chloroplasts. However, in the absence of light, proplastids undergo a different sequence of development and become etioplasts. When light is supplied to etiolated plants during the "greening" process, etioplasts differentiate into chloroplasts containing chlorophyll. An important light dependent step in chlorophyll biosynthesis is the photoreduction of protochlorophyllide to chlorophyllide by the NADPH:protochlorophyllide reductase (PCR) enzyme. This enzyme is present at high activity only in etiolated tissue and during early stages of light-induced chlorophyll synthesis. The enzyme and its corresponding mRNAs decrease dramatically with prolonged exposure to light. We have investigated the light-dependent transcriptional regulation of a PCR gene in greening maize leaf cells using a transient expression assay based on microprojectile bombardment. The promoter region was isolated and cloned into a ?-glucuronidase (GUS) reporter gene expression plasmid. We have used this chimeric plasmid in tungsten particle bombardment of both etiolated and greening maize seedling leaves to determine whether the cloned promoter region contains regulatory sequences that control light-responsive PCR gene expression.

Protective effect of simvastatin in the cyclophosphamide-induced hemohrragic cystitis in rats

Cyclophosphamide (CYP) is an antineoplastic agent used for the treatment of many neoplastic and inflammatory diseases. Hemorrhagic cystitis is a frequent side effect of CYP. Several studies show that simvastatin has important pleiotropic (anti-inflammatory and immunomodulatory) effects. The purpose of the study was to investigate the effect of simvastatin on bladder, ureter and kidney injury caused by CYP. Methods: Adult male Wistar rats were randomly divided into three groups. The CYP/SIM group received simvastatin microemulsion by gavage during 7 days (10 mg/kg body wt) before the administration of CYP and the CYP/SAL group rats received saline 0.9%. The control rats were not treated. After that, all rats were treated with a single dose of CYP 200 mg/kg body wt intraperitoneally. The rats were killed 24 h after CYP administration. Plasma cytokines (TNF-a, IL-1b, IL-6) were measured by ELISA. Macro and light microscopic study was performed in the bladder, kidney and ureter. Results: In the bladders of CYP/SIMV treated rats edema of lamina propria with epithelial and sub-epithelial hemorrhage were lower than in CYP/SAL treated rats. The scores for macroscopic and microscopic evaluation of bladder and ureter were significantly lower in CYP/SIMV rats than in CYP/SAL rats. The kidney was not affected. The expression of TNF-a, IL-1b and IL-6 was significatly lower in CF/SINV rats (164.8±22, 44.8±8 and 52.4±13) than in CF/SAL rats (378.5±66, 122.9±26 e 123.6±18), respectively. Conclusion: The results of the current study suggest that simvastatin pretreatment attenuated CYP-induced urotelium inflammation and decreased the activities of cytokines

On the interaction of bovine serum albumin with ionic surfactants: Temperature induced EPR changes of a maleimide nitroxide reflect local protein dynamics and probe solvent accessibility

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Molecular mapping of the viral determinants of systemic wilting induced by a Lettuce mosaic virus (LMV) isolate in some lettuce cultivars

The isolate AF199 of Lettuce mosaic virus (LMV, genus Potyvirus) causes local lesions followed by systemic wilting and plant death in the lettuce cultivars Ithaca and Vanguard 75. Analysis of the phenotype of virus chimeras revealed that a region within the PI protein coding region (nucleotides 112-386 in the viral genome) and/or another one within the CI protein coding region (nucleoticles 5496-5855) are sufficient together to cause the lethal wilting in Ithaca, but not in Vanguard 75. This indicates that the determinants of this particular symptom are different in these two lettuce cultivars. The wilting phenotype was not directly correlated with differences in the deduced amino acid sequence of these two regions. Furthermore, transient expression of the LMV-AF 199 proteins, separately or in combination, did not induce local necrosis or any other visible reaction in the plants. Together, these results Suggest that the systemic wilting reaction might be Clue to RNA rather than protein sequences. (c) 2004 Elsevier B.V. All rights reserved.

Voltammetric performance and application of a sensor for sodium ions constructed with layered birnessite-type manganese oxide

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Physical Vapor Deposited Thin Films of Lignins Extracted from Sugar Cane Bagasse: Morphology, Electrical Properties, and Sensing Applications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Matemal separation affects cocaine-induced locomotion and response to novelty in adolescent, but not in adult rats

Maternal separation is known to exert long-term effects on both behavior and the neuroendocrine system. We investigated cocaine-induced locomotor activation as well as the locomotor and corticosterone response to forced novelty in maternally separated adolescent and adult rats. Maternal separation consisted of separating litters from their darns daily during 5 h from postnatal days 2 to 6. Control animals were subjected only to regular cage changes. Cocaine- (10 mg/kg, i.p.) and novelty-induced locomotion were recorded in an activity cage. After the animals were tested for behavioral response to novelty, trunk blood samples were collected and plasma corticosterone levels were determined by radioimmunoassay. Adolescent rats exposed to maternal separation exhibited an increased locomotor response to novelty and cocaine; corticosterone levels were lower in these adolescent animals, after exposure to the novel environment. These effects of materrial separation were not observed in rats that were tested as adults. Thus the maternal separation protocol produced enduring but transient changes in the behavioral response to cocaine and in the stress response to novelty. (C) 2004 Elsevier B.V. All rights reserved.

Comparative effects of acute and subacute lycopene administration on chromosomal aberrations induced by cisplatin in male rats

Lycopene is a natural carotenoid, free radical scavenger, and presents protective effects by inhibiting oxidative DNA damage. The objective of the current study was to investigate the cytogenetic effects of a single acute and four daily gavage administrations of lycopene, and to examine possible protective effects on chromosomal damage induced by the antitumor drug cisplatin (cDDP) in rat bone marrow cells. The animals were divided into treatment groups, with three lycopene doses in the acute treatment (2, 4, and 6 mg/kg b.w.), three lycopene doses in the subacute treatment (0.5, 1.0, and 1.5 mg/kg b.w.) with and without cDDP (5 mg/kg b.w. i.p.), and respective controls. The results indicated that lycopene is neither cytotoxic nor clastogenic when compared with the negative controls (P > 0.01). cDDP-treated animals submitted to acute and subacute treatments with different lycopene doses showed a significant reduction (p < 0.01) in the number of abnormal metaphases when compared with the animals treated only with cDDP. The protective effects of lycopene on cDDP-induced chromosomal damage may be attributed to its antioxidant activity. These results suggest that this carotenoid may prove useful in reducing some of the toxic effects associated with certain classes of chemotherapeutic agents. (c) 2006 Elsevier Ltd. All rights reserved.

Structural Properties Induced by the Composition of Biocompatible Phospholipid-Based Microemulsion and Amphotericin B Association

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)