Produtos naturais da ascídia Botrylloides giganteum, das esponjas Verongula gigantea, Ircinia felix, Cliona delitrix e do nudibrânquio Tambja eliora, da costa do Brasil

Two new marine metabolites, 3Z, 6Z, 9Z-dodecatrien-1-ol (1) from the ascidian Botrylloides giganteum and 4H-pyran-2ol acetate from the sponge Ircinia felix (4) are herein reported. The known bromotyrosine compounds, 2-(3,5-dibromo-4-methoxyphenyl)-N,N,N-dimethylethanammonium (2) and 2,6-dibromo-4-(2-(trimethylammonium)ethyl)phenol (3), have been isolated from the sponge Verongula gigantea. Serotonin (5) is reported for the first time from the sponge Cliona delitrix, and tambjamines A (15) and D (16) isolated as their respective salts from the nudibranch Tambja eliora. Only tambjamine D presented cytotoxicity against CEM (IC50 12.2 µg/mL) and HL60 (IC50 13.2 µg/mL) human leukemya cells, MCF-7 breast cancer cells (IC50 13.2 µg/mL), colon HCT-8 cancer cells (IC50 10.1 µg/mL) and murine melanoma B16 cancer cells (IC50 6.7 µg/mL).

Composição química da precipitação atmosférica no sul do Brasil: estudo preliminar

The present work is a preliminary study of total and wet precipitation in the Candiota region, RS. The samples were collected from January to June 2001 at four different sites. The following variables were analysed: pH, conductivity, alkalinity, Cl-, NO3-, F-, SO4(2-), Na+, K+, Mg2+, NH4+, Ca2+ and Zn, Cu, Fe, Al, Mn. The results showed slightly acidic precipitation and higher concentrations of NH4+, Na+, Cl- and SO4(2-). Factor analysis applied to the variables studied allowed identifying the major sources. Na+, Cl- and Mg2+ have their origin in sea salts and NH4+, Ca2+, K+, SO4(2-) and NO3- are from local anthropogenic sources.

Determinação indireta de N-acetil-L-cisteína por injeção em fluxo empregando Ce(IV) e ferroína

An indirect flow injection spectrophotometric procedure is proposed for the determination of N-acetyl-L-cysteine in pharmaceutical formulations. In this system, ferroin ([Fe(II)-(fen)2]2+) in excess, with a strong absorption at 500 nm, is oxidized by cerium(IV) yielding cerium(III) and [Fe(III)-(fen)2]3+ (colorless), thus producing a baseline. When N-acetyl-L-cysteine solution is introduced into the flow injection system, it reacts with cerium(IV) increasing the analytical signal in proportion to the drug concentration. Under optimal experimental conditions, the linearity of the analytical curve for N-acetyl-L-cysteine ranged from 6.5x10-6 to 1.3x10-4 mol L-1. The detection limit was 5.0x10-6 mol L-1and recoveries between 98.0 and 106% were obtained. The sampling frequency was 60 determinations per hour and the RSD was smaller than 1.4% for 2.2x10-5 mol L-1 N-acetyl-L-cysteine.

Sistema aquoso bifásico: uma alternativa eficiente para extração de íons

Solvent extraction has been successfully applied to metal ion preconcentration and often meant the use of toxic organic diluents. However, regulatory pressure is increasingly focusing on the use and disposal of organic solvents, and thus the development of nonhazardous alternatives is important. In this review, we examine the application of aqueous biphasic systems (ABS) to extraction of ions, analyzing their potential and limitations and suggest that ABSs could be an efficient substitute for oil/water biphasic systems. ABSs are formed by mixing certain inorganic salts and water-soluble polymers, or by mixing two water-soluble polymers.

Paineviemärissä muodostuvan rikkivedyn vähentäminen kemikaloimalla

Anaerobisissa olosuhteissa muodostuva rikkivetykaasu on tyypillinen ongelma etenkin pitkillä paineviemäriosuuksilla. Sille ominainen epämiellyttävä haju aiheuttaa jätevedenkäsittelyverkostoissa ja viemärilinjojen lähialueilla merkittäviä hajuongelmia. Lisäksi rikkivedyn hapettuessa rikkihapoksi viemäri joutuu alttiiksi korroosiolle. Helsingin Etelä rannassa sijaitsevaan Munkkisaareen päätyy 4,4 km pitkä paineviemäri. Viemärin tuuletusputken kautta leviävä rikkivety on aiheuttanut hajuongelmia alueella. Korkeimmat mitatut rikkivetypitoisuudet tuuletusputken läheisyydessä olivat jopa 300 ppm. Tutkimuksessa tehtiin koeajoja erilaisilla hajunpoistokemikaaleilla rikkivetyongelman ratkaisemiseksi. Viemäriin annosteltiin sen alkupäässä jatkuvatoimisesti ferrosulfaattia ja ferrinitraattisulfaattia, sekä shokki-käsittelyllä natriumhydroksidia (lipeää). Munkkisaaressa mitatut rikkivetypitoisuudet osoittivat käytettyjen kemikaalien tehokkuuden rikkivedyn poistossa. Rikkivedyn saostamiseen tarkoitetut rautasuolat (ferrosulfaatti ja ferrinitraattisulfaatti) vähensivät 100 - 150 g annoksilla rikkivetyä yli 90 prosenttia. Natriumhydroksin annoksella 3600 g/m³ viemärin mikrobiologinen toiminta voitiin estää keskimäärin kymmeneksi päiväksi, mutta tehokas rikkivedyn muodostumisen esto vaatisi käsittelyn uusimisen noin 5 päivän välein. Normaaleissa viemärin olosuhteissa rikkivetyä muodostui vuorokauden aikana yhtä neliömetriä kohden noin 10 g. Kemikaalikäsittelyjen avulla muodostuminen aleni parhaimmillaan kymmenesosaan alkuperäisestä. Tulosten perusteella kemikaalien käytöllä viemärissä voisi välttyä kalliilta saneeraukselta Munkkisaaressa sekä muissa korroosiolle alttiiksi joutuvissa viemäreissä. Kemikalointikustannukset rautasuoloilla olivat noin 11 000 - 34 000 € ja lipeällä noin 7 000 € vuodessa.

Processamento de pilhas Li/MnO2 usadas

This work presents two recycling processes for spent Li/MnO2 batteries. After removal of the solvent under vacuum the cathode + anode + electrolyte was submitted to one of the following procedures: (a) it was calcined (500 ºC, 5 h) and the calcined solid was submitted to solvent extraction with water in order to recover lithium salts. The residual solid was treated with sulfuric acid containing hydrogen peroxide. Manganese was recovered as sulfate; (b) the solid was treated with potassium hydrogeno sulfate (500 ºC, 5 h). The solid was dissolved in water and the resulting solution was added dropwise to sodium hydroxide. Manganese was recovered as dioxide. The residual solution was treated with potassium fluoride in order to precipitate lithium fluoride.

Recuperação de cobalto e de lítio de baterias íon-lítio usadas

The "active mass" (cathode + anode + electrolyte) of spent Li-ion batteries was submitted to one of the following procedures: (a) it was calcined (500 ºC) and submitted to extraction with water to recover lithium salts. The residual solid was treated with sulfuric acid containing hydrogen peroxide. Cobalt was recovered as sulfate; (b) the "active mass" was treated with potassium hydrogen sulfate (500 ºC) and dissolved in water. Cobalt was precipitated together with copper after addition of sodium hydroxide. Lithium was partially recovered as lithium fluoride. Co-processing of other battery components (aluminum and copper foils) affected negatively the behavior of the recovery procedures. Previous segregation of battery components is essential for an efficient and economical processing of the "active mass".

Antimycobacterial and cytotoxicity activity of synthetic and natural compounds

Antimycobacterial and cytotoxicity activity of synthetic and natural compounds. Secondary metabolites from Curvularia eragrostidis and Drechslera dematioidea, Clusia sp. floral resin, alkaloids from Pilocarpus alatus, salicylideneanilines, piperidine amides, the amine 1-cinnamylpiperazine and chiral pyridinium salts were assayed on Mycobacterium tuberculosis H37Rv. N-(salicylidene)-2-hydroxyaniline was the most effective compound with a minimal inhibitory concentration (MIC) of 8 µmol/L. Dihydrocurvularin was moderately effective with a MIC of 40 µmol/L. Clusia sp. floral resin and a gallocatechin-epigallocatechin mixture showed MIC of 0.02 g/L and 38 µmol/L, respectively. The cytotoxicity was evaluated for N-(salicylidene)-2-hydroxyaniline, curvularin, dihydrocurvularin and Clusia sp. floral resin, and the selectivity indexes were > 125, 0.47, 0.75 and 5, respectively.

Cério: propriedades catalíticas, aplicações tecnológicas e ambientais

Cerium based-compounds have great importance in a wide range of technological applications, such as: fuel cell devices development; metallurgic processes, petroleum refining; glass and ceramic production. Recently, its catalytic properties have been also explored for environmental applications, especially those to prevent or to control atmospheric and water pollution. Subjects covered in this work include a brief description of the fundaments of cerium catalytic properties and some relevant technological applications. Special attention is given to its photocatalytic activity and its ability to degrade pollutants. Recent results and future prospect about these applications are also evaluated.

Influence of the temperature and type of salt on the phase equilibrium of peg 1500 + potassium phosphate and peg 1500 + sodium citrate aqueous two-phase systems

The present work analyzed the effect of the temperature and type of salt on the phase equilibrium of aqueous two-phase systems (ATPS) formed by poly (ethylene glycol) (PEG) 1500 + potassium phosphate, from (278.15 to 318.15) K, and PEG 1500 + sodium citrate, from (278.15 to 298.15) K. The rise of the temperature normally increased the slope of the tie line (STL). With respect to the influence of the type of salt, sodium citrate showed better capability to induce phase separation, when compared to potassium phosphate.

Treatment of oily wastewater by ultrafiltration: The effect of different operating and solution conditions

In many industries, such as petroleum production, and the petrochemical, metal, food and cosmetics industries, wastewaters containing an emulsion of oil in water are often produced. The emulsions consist of water (up to 90%), oils (mineral, animal, vegetable and synthetic), surfactants and other contaminates. In view of its toxic nature and its deleterious effects on the surrounding environment (soil, water) such wastewater needs to be treated before release into natural water ways. Membrane-based processes have successfully been applied in industrial applications and are considered as possible candidates for the treatment of oily wastewaters. Easy operation, lower cost, and in some cases, the ability to reduce contaminants below existing pollution limits are the main advantages of these systems. The main drawback of membranes is flux decline due tofouling and concentration polarisation. The complexity of oil-containing systems demands complementary studies on issues related to the mitigation of fouling and concentration polarisation in membranebased ultrafiltration. In this thesis the effect of different operating conditions (factors) on ultrafiltration of oily water is studied. Important factors are normally correlated and, therefore, their effect should be studied simultaneously. This work uses a novel approach to study different operating conditions, like pressure, flow velocity, and temperature, and solution properties, like oil concentration (cutting oil, diesel, kerosene), pH, and salt concentration (CaCl2 and NaCl)) in the ultrafiltration of oily water, simultaneously and in a systematic way using an experimental design approach. A hypothesis is developed to describe the interaction between the oil drops, salt and the membrane surface. The optimum conditions for ultrafiltration and the contribution of each factor in the ultrafiltration of oily water are evaluated. It is found that the effect on permeate flux of the various factors studied strongly depended on the type of oil, the type of membrane and the amount of salts. The thesis demonstrates that a system containing oil is very complex, and that fouling and flux decline can be observed even at very low pressures. This means that only the weak form of the critical flux exists for such systems. The cleaning of the fouled membranes and the influence of different parameters (flow velocity, temperature, time, pressure, and chemical concentration (SDS, NaOH)) were evaluated in this study. It was observed that fouling, and consequently cleaning, behaved differently for the studied membranes. Of the membranes studied, the membrane with the lowest propensity for fouling and the most easily cleaned was the regenerated cellulose membrane (C100H). In order to get more information about the interaction between the membrane and the components of the emulsion, a streaming potential study was performed on the membrane. The experiments were carried out at different pH and oil concentration. It was seen that oily water changed the surface charge of the membrane significantly. The surface charge and the streaming potential during different stages of filtration were measured and analysed being a new method for fouling of oil in this thesis. The surface charge varied in different stages of filtration. It was found that the surface charge of a cleaned membrane was not the same as initially; however, the permeability was equal to that of a virgin membrane. The effect of filtration mode was studied by performing the filtration in both cross-flow and deadend mode. The effect of salt on performance was considered in both studies. It was found that salt decreased the permeate flux even at low concentration. To test the effect of hydrophilicity change, the commercial membranes used in this thesis were modified by grafting (PNIPAAm) on their surfaces. A new technique (corona treatment) was used for this modification. The effect of modification on permeate flux and retention was evaluated. The modified membranes changed their pore size around 33oC resulting in different retention and permeability. The obtained results in this thesis can be applied to optimise the operation of a membrane plant under normal or shock conditions or to modify the process such that it becomes more efficient or effective.

Ciclização do lapachol induzida por sais de tálio III

This work describes the cyclization of lapachol (1) induced by thallium triacetate (TTA) and thallium trinitrate (TTN) in several solvents using magnetic stirring and under microwave irradiation. alpha-Xyloidone (2) - dehydro-alpha-lapachone - was obtained as the main product in these reactions in 20 75% yield. However, rhinacanthin-A (4) was isolated as main product in a 40% yield, using TTA and acetic anhydride:water (1:1) as solvent, and dehydro-iso-alpha-lapachone (3) in 21% yield, using TTA and dichloromethane as solvent. The reaction time decreased drastically under microwave conditions, but the yields of these reactions were not the expected.

Entalpía de disolución de sulfacetamida sódica en agua: comparación entre la calorimetría isoperibólica de solución y el método de van't Hoff

The dissolution enthalpy (ΔH0soln) of sodium sulfacetamide in water was determined by means of isoperibolic solution calorimetry. It was found that ΔH0soln diminishes as the drug concentration increases. Otherwise, the calorimetric values obtained as a function of the drug concentration were significantly different than those predicted by the van't Hoff method. It was demonstrated that the later is not a fully reliable method for the determination of ΔH0soln values in the specific case of highly soluble sodium salts. The observed phenomenon could be explained by the presence of strong solute-solute interactions at high salt concentrations, in addition to solute-solvent and solvent-solvent interactions.

Estudos termoanalíticos de sais de sódio e potássio de ditiocarbamatos em atmosfera oxidante

Thermoanalytical behavior of sodium and potassium salts of pyrrolidinedithiocarbamate (pyr), piperidineditiocarbamate (pip), morpholinedithiocarbamate (mor), hexametileneiminedithiocarbamate (hex), were investigated. In a first step the salts were synthesized and characterized by infrared spectroscopy (FTIR), ¹H and 13C nuclear magnetic resonance (NMR) and elementar analysis. Finally, thermal analytical (TG/DTG and DSC) studies were performed in order to evaluate the thermal stability, as well as the pathways of the thermal decomposition based in the intermediate and final decomposition products.

Síntese, caracterização e análise térmica dos sais de lítio, sódio e potássio do ácido palmítico e do seu éster etílico

Alkaline salts of the palmitic acid were synthesized and characterized from aqueous and ethanolic medium. The salts were characterized by elemental analysis (EA) and infrared spectroscopy (IR). EA and IR, being its synthesis comproved, also characterized the ethyl palmitate. All the salts and the ester were submitted to thermal analysis using thermogravimetry (TG), and differential thermal analysis (DTA) in the temperature ranging from room to 700 ºC under air dynamic atmosphere. Differential scanning calorimetry (DSC) measurements were taken from -90 ºC up to temperatures close to the starting of the decomposition temperature, determined by thermogravimetry, using heating and cooling cycles.