A comprehensive insight into floc characteristics and their impact on compressibility and settleability of activated sludge

This paper presents a comprehensive study of sludge floc characteristics and their impact on compressibility and settleability of activated sludge in full scale wastewater treatment processes. The sludge flocs were characterised by morphological (floc size distribution, fractal dimension, filament index), physical (flocculating ability, viscosity, hydrophobicity and surface charge) and chemical (polymeric constituents and metal content) parameters. Compressibility and settleability were defined in terms of the sludge volume index (SVI) and zone settling velocity (ZSV). The floc morphological and physical properties had important influence on the sludge compressibility and settleability. Sludges containing large flocs and high quantities of filaments, corresponding to lower values of fractal dimension (D-f), demonstrated poor compressibility and settleability. Sludge flocs with high flocculating ability had lower SVI and higher ZSV, whereas high values of hydrophobicity, negative surface charge and viscosity of the sludge flocs correlated to high SVI and low ZSV. The quantity of the polymeric compounds protein. humic substances and carbohydrate in the sludge and the extracted extracellular polymeric substances (EPS) had significant positive correlations with SVI. The ZSV was quantitatively independent of the polymeric constituents. High concentrations of the extracted EPS were related to poor compressibility and settleability. The cationic ions Ca, Mg, Al and Fe in the sludge improved significantly the sludge compressibility and settleability. (C) 2003 Elsevier Science B.V. All rights reserved.

Insights into the structural basis for zinc inhibition of the glycine receptor

Histidines 107 and 109 in the glycine receptor ( GlyR) alpha(1) subunit have previously been identified as determinants of the inhibitory zinc-binding site. Based on modeling of the GlyR alpha(1) subunit extracellular domain by homology to the acetylcholine-binding protein crystal structure, we hypothesized that inhibitory zinc is bound within the vestibule lumen at subunit interfaces, where it is ligated by His(107) from one subunit and His(109) from an adjacent subunit. This was tested by co-expressing alpha(1) subunits containing the H107A mutation with alpha(1) subunits containing the H109A mutation. Although sensitivity to zinc inhibition is markedly reduced when either mutation is individually incorporated into all five subunits, the GlyRs formed by the co-expression of H107A mutant subunits with H109A mutant subunits exhibited an inhibitory zinc sensitivity similar to that of the wild type alpha(1) homomeric GlyR. This constitutes strong evidence that inhibitory zinc is coordinated at the interface between adjacent alpha(1) subunits. No evidence was found for beta subunit involvement in the coordination of inhibitory zinc, indicating that a maximum of two zinc-binding sites per alpha(1)beta receptor is sufficient for maximal zinc inhibition. Our data also show that two zinc-binding sites are sufficient for significant inhibition of alpha(1) homomers. The binding of zinc at the interface between adjacent alpha(1) subunits could restrict intersubunit movements, providing a feasible mechanism for the inhibition of channel activation by zinc.

Chemical characterisation of deep profile Ferrosols under sugarcane in wet tropical northern Queensland

The chemical properties of deep profile samples ( up to 12 m) of Ferrosols from northern Queensland were investigated to provide an understanding of the accumulation of nitrate ( NO3) within these soil profiles. The influence of other cations and anions present in the soil solution or on the exchange and the charge chemistry of the profiles were examined with respect to the NO3 accumulations. The major ions in the soil solution were Na, NO3, and chloride ( Cl). Distinct regions of anion accumulation were observed; SO4 accumulated in the upper profile of all cores, whereas NO3 and Cl accumulations were restricted to the lower profile of cores with appreciable AEC (> 1 cmol(c)/kg). Gaines-Thomas selectivity coefficients were used to indicate exchange preference for cations and anions, and are as follows: Al > Ca similar to Mg > K > Na and sulfate (SO4) > Cl similar to NO3. The selectivity of SO4 increased and the extractable SO4 decreased in the lower profile of all cores. This has important implications for the adsorption of NO3 and Cl. The NO3 and Cl accumulations were shown to correspond to a region of low SO4 occupancy of the exchange sites in the lower profile. Along with the high SO4 selectivity, this suggests that SO4 may control the positioning of the NO3 accumulations. It was concluded that the NO3 accumulations were relatively stable under current management practices, although the reduction in NO3 inputs would likely see the gradual replacement of NO3 with Cl as a result of their comparable selectivity for exchange sites.

Geometric isomers of chloro(6-methyl-1,4,8,11-tetraazacyclotetradecane-6-amine)cobalt(III) tetrachlorozincate(II)

The crystal structures of a pair of cis and trans isomers of the macrocyclic chloropentaamine title complex, as their tetrachlorozincate(II) salts, [CoCl(C11H27N5)][ZnCl4], are reported. The two distinct isomeric forms lead to significant variations in the Co-N bond lengths and, furthermore, hydrogen bonding between the complex ions is influenced by the folded (cis) or planar (trans) conformations of the coordinated ligand.

Potential for early involvement of CYP isoforms in aspects of human cadmium toxicity

This paper investigates the possible link between non-workplace cadmium (Cd) exposure, cytochrome P450 expression and hypertension. We present results of our investigation into the relationships between liver and kidney Cd burdens and the abundance of the CYP isoform 4A11. Our data show associations between non-workplace Cd exposure and changes in the abundance of hepatic and renal cortical CYP4A11. In liver the levels of immunochemically detectable CYP4A11 were positively correlated with tissue Cd content while in contrast CYP4A11 abundance was inversely correlated with kidney Cd burden. These differences are most likely related to the different Cd burden of the tissues. These observations suggest the potential for involvement of Cd as a mediator of CYP4A11 expression in kidney cortex and indicate that elevations in kidney Cd content may be involved in hypertension via alteration of the expression of this particular isoform. Potential mechanisms by which Cd may alter CYP4A11 expression are discussed briefly. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Structural variations and formation constants of first-row transition metal complexes of biologically active aroylhydrazones

Iron chelators of the 2-pyridinecarbaldehyde isonicotinoylhydrazone (HPCIH) class show high potential for the treatment of iron overload diseases. In the present study, selected first-row transition metal (from Mn to Zn) complexes with HPCIH and 2-pyridinecarbaldehyde (4'-aminobenzoyl)hydrazone (HPCAH) were synthesised and characterised. Crystallography reveals that HPCAH exclusively forms bis complexes with divalent transition metals, with each ligand coordinating meridionally through its pyridine-N, imine-N and carbonyl-O atoms, forming distorted octahedral cis-MN4O2 complexes. Complexes of HPCIH were more varied and unpredictable, with metal/ligand ratios of 1:1, 1:2, 2:2 and 3:2 obtained with different metal ions. The isonicotinoyl ring N-atom in HPCIH was found to be an effective ligand, and this resulted in the varied metal/ligand ratios observed. The formation constants of divalent metal complexes with HPCIH were determined by potentiometric titrations and the values obtained were consistent with similar tridentate ligands and with the Irving-Williams order. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

Identifica����o Qu��mica em N��vel Molecular de Amostras de Maconha por ESI-FT-ICR MS

mais consumida no pa��s, e proscrita pela Lei n�� 11.343 de 23 de agosto de 2006 (chamada de ���nova lei de droga���), onde todos os is��meros, sais, ��teres e ��steres do ���9-Tetrahidrocannabinol (THC), princ��pio ativo, foram proscritos. O m��todo utilizado pela Pol��cia Civil do Estado do Esp��rito Santo para a identifica����o de cannabin��ides �� o teste colorim��trico, por meio de solu����o b��sica de Salt Fast Blue B, o qual apresenta resultados falsos negativos e falsos positivos. A t��cnica de espectrometria de massas de alt��ssima resolu����o e exatid��o de massas (ESI(-)FTICR MS), permite detectar os principais cannabin��ides na forma de mol��cula desprotonada, ��on [M-H]-. Alguns ��ons que podem ser identificados s��o: [CBN - H]- de m/z 309 (CBN = cannabinol); [THC - H]- de m/z 313 (THC = tetrahidrocannabinol) e [CBD - H]- de m/z 313; [CBC - H]- de m/z 327 (CBC = cannabicromeno); [CBEA - H]- de m/z 345 (CBEA = ��cido cannabiels��ico); [CBNA - H]- de m/z 353 (CBNA = ��cido cannabin��lico); [THCA - H]- de m/z 357 (THCA = ��cido tetrahidrocannabin��lico); [8��, 11-Bis-hydroxy-���9-THC-A - H]- de m/z 389); [���9-THCA +C2H2O - H]- de m/z 357; e d��meros com m/z de 637, 653, 673, 681, 685 e 717. Foram encontrados adulterantes identificados como [M + N + H]+ : 491; [2M + N + H]+ : 819 e [3M + N + H]+ : 1147, onde M = OTHC (328Da C21H28O3) e N = Nicotina (162Da C10H14N2), al��m de lidoca��na e coca��na. Ainda foram identificados alguns noncannabin��ides como Cannflavino A e B e ��cidos graxos como palm��tico, oleico, linol��nico e gama-linol��nico nos extratos de sementes de Cannabis. Este estudo tem o objetivo de identificar o perfil qu��mico de amostras de maconha, apreendidas pela Pol��cia Civil do Estado do Esp��rito Santo, por ESI(��)-FT-ICR MS.

An��lise de Parafinas por APCI-FT-ICR MS : Uma An��lise R��pida e Simples na Identifica����o de Hidrocarbonetos Saturados, C��clicos e Poliarom��ticos

A an��lise de hidrocarbonetos por t��cnicas de ioniza����o a press��o atmosf��rica ou ambiente continua a ser um desafio na espectrometria de massas. Normalmente, a ioniza����o ocorre atrav��s de mecanismos de protona����o e desprotona����o. Para isso, as mol��culas de interesse devem apresentar um grupo b��sico ou ��cido que proporcionem a gera����o de ��ons [M+H]+ ou [M-H]-. Para superar essa limita����o, um m��todo anal��tico simples, f��cil, r��pido e poderoso foi desenvolvido com sucesso, adaptado a partir da literatura, para ionizar saturado e insaturado, linear, ramificado, e hidrocarbonetos c��clicos, bem como hidrocarbonetos poliarom��ticos e heteroarom��ticos presentes em fra����es de hidrocarbonetos e de misturas de parafina/petr��leo bruto utilizando ioniza����o qu��mica �� press��o atmosf��rica (APCI), favorecido pela utiliza����o de solventes alif��ticos de cadeia curta em um espectr��metro de massas FT-ICR. Entre os reagentes alif��ticos estudados, isoctano proporcionou os melhores resultados quando comparado com outros solventes. Al��m disso, foram estudados outros interferentes do processo de ioniza����o, como concentra����o da solu����o injetada e misturas parafina/��leo, que influenciavam desde o perfil dos espectros at�� as principais classes de compostos identificados. O m��todo torna poss��vel a ioniza����o de hidrocarbonetos pela produ����o de ��ons [M -H]+ sem ocorr��ncia de fragmenta����o.

Influ��ncia de temperatura, luz e giberelina na germina����o de sementes de Thlaspi caerulescens J. Presl & C. Presl (Brassicaceae)

Thlaspi caerulescens �� esp��cie hiperacumuladora de metais como Cd2+, Ni2+ e Zn2+, considerada como uma plantamodelo para estudar a acumula����o e toler��ncia a metais pesados. No entanto, a baixa produ����o de sementes em nossas condi����es clim��ticas tornam necess��ria a determina����o de condi����es que possam maximizar a germina����o e o vigor de suas sementes. Para identificar as melhores condi����es para a germina����o, sementes de T. caerulescens foram colocadas na presen��a (15 mmol.m-2.s-1, 8 h luz/16 h escuro) ou aus��ncia de luz nas temperaturas de 10, 15, 20 e 25 ��C, em papel germitest previamente umedecido com solu����o de ��cido giber��lico (GA3) a 0,05% ou ��gua destilada. Foram avaliados a porcentagem de germina����o (%G) e o ��ndice de velocidade de germina����o (IVG). Maior porcentagem de germina����o (66%) foi observada nos tratamentos com GA3 e temperaturas de 15 e 20 ��C, na presen��a de luz. Maiores valores do IVG foram obtidos com a utiliza����o de GA3 nas temperaturas de 15 e 20 ��C, tanto na presen��a quanto na aus��ncia de luz. Maiores germina����o e IVG de T. caerulescens foram observados com uso de GA3 na presen��a de luz nas temperaturas de 15 e 20 ��C.

Solubilization of diabase and phonolite dust by filamentous fungus

The objective of this study was to evaluate the effect of the fungus Aspergillus niger strain CCT4355 in the release of nutrients contained in two types of rock powder (diabase and phonolite) by means of in vitro solubilization trials. The experimental design was completely randomized in a 5 x 4 factorial design with three replications. It was evaluated five treatments (phonolite dust + culture medium; phonolite dust + fungus + culture medium; diabase powder + culture medium; diabase powder + fungus + culture medium and fungus + culture medium) and four sampling dates (0, 10, 20 and 30 days). Rock dust (0.4% w/v) was added to 125 mL Erlenmeyer flasks containing 50 mL of liquid culture medium adapted to A. niger. The flasks were incubated at 30��C for 30 days, and analysis of pH (in water), titratable acidity, and concentrations of soluble potassium, calcium, magnesium, zinc, iron and manganese were made. The fungus A. niger was able to produce organic acids that solubilized ions. This result indicates its potential to alter minerals contained in rock dust, with the ability to interact in different ways with the nutrients. A significant increase in the amount of K was found in the treatment with phonolite dust in the presence of the fungus. The strain CCT4355 of A. niger can solubilize minerals contained in these rocks dust.

Cristaliza����o de Biomateriais Vitrocer��micos e Mineraliza����o em Meio Fisiol��gico Simulado

We propose new theoretical models, which generalize the classical Avrami-Nakamura models. These models are suitable to describe the kinetics of nucleation and growth in transient regime, and/or with overlapping of nucleation and growth. Simulations and predictions were performed for lithium disilicate based on data reported in the literature. One re-examined the limitations of the models currently used to interpret DTA or DSC results, and to extract the relevant kinetic parameters. Glasses and glass-ceramics with molar formulation 0.45SiO2? (0.45-x)MgO?xK2O?0.1(3CaO.P2O5) (0?x?0.090) were prepared, crystallized and studied as potential materials for biomedical applications. Substitution of K+ for Mg2+ were used to prevent devritification on cooling, to adjust the kinetics of crystallization and to modify the in vitro behaviour of resulting biomaterials. The crystallization of the glass frits was studied by DTA, XRD and SEM. Exothermic peaks were detected corresponding to bulk crystallization of whitlockite-type phosphate, Ca9MgK(PO4)7, at approximately 900��C, and surface crystallization of a predominant forsterite phase (Mg2SiO4) at higher temperatures. XRD also revealed the presence of diopside (CaMgSi2O6 in some samples. The predominant microstructure of the phosphate phase is of the plate-type, seemingly crystallizing by a 2-dimensional growth mechanism. Impedance spectroscopy revealed significant changes in electrical behaviour, associated to crystallization of the phosphate phase. This showed that electrical measurements can be used to study the kinetics of crystallization for cases when DTA or DSC experiments reveal limitations, and to extract estimates of relevant parameters from the dependence of crystallization peak temperature, and its width at half height. In vitro studies of glasses and glass-ceramics in acelular SBF media showed bioactivity and the development of apatite layers The morphology, composition and adhesion of the apatite layer could be changed by substitution of Mg2+ by K+. Apatite layers were deposited on the surface of glass-ceramics of the nominal compositions with x=0 and 0.09, in contact with SBF at 37��C. The adhesion of the apatite layer was quantified by the scratch test technique, having been related with SBF?s immersion time, with composition and structure of the glass phase, and with the morphology of the crystalline phase of the glass-ceramics. The structure of three glasses (x=0, 0.045 and 0.090) were investigated by MAS-NMR ( 29Si and 31P), showing that the fraction of Q3 structural units increases with the contents of Mg, and that the structure of these glasses includes orthophosphate groups (PO43-) preferentially connected to Ca2+ ions. Mg2+ ions show preference towards the silicate network. Substitution of Mg2+ by K+ allowed one to change the bioactivity. FTIR data revealed octacalcium phosphate precipitation (Ca8H2(PO4)6.5H2O) in the glass without K, while the morphology of the layer acquires the shape of partially superimposed hemispheres, spread over the surface. The glasses with K present a layer of acicular hidroxyapatite, whose crystallinity and needles thickness tend to increase along with K content.

Burn wood influence on outdoor air quality in a small village: Foros de Arr��o, Portugal

One Plus Sequential Air Sampler���Partisol was placed in a small village (Foros de Arr��o) in central Portugal to collect PM10 (particles with an aerodynamic diameter below 10 ��m), during the winter period for 3 months (December 2009���March 2010). Particles masses were gravimetrically determined and the filters were analyzed by instrumental neutron activation analysis to assess their chemical composition. The water-soluble ion compositions of the collected particles were determined by Ion-exchange Chromatography. Principal component analysis was applied to the data set of chemical elements and soluble ions to assess the main sources of the air pollutants. The use of both analytical techniques provided information about elemental solubility, such as for potassium, which was important to differentiate sources.

Desenfumagem em edif��cios: parque de estacionamento coberto (retail - Oeiras parque)

Os parques de estacionamento surgiram da necessidade de disponibiliza����o de espa��o de parqueamento de ve��culos que fazem parte do quotidiano do Homem, no entanto devido ao facto de poderem ser confinados ou subterr��neos requerem a instala����o de ventila����o for��ada (ventiladores axiais e ventiladores de impulso). Este trabalho tem como objectivo a an��lise, utilizando m��todos de simula����o num��rica da ventila����o for��ada criada pelos ventiladores de impulso e pelos ventiladores axiais instalados num parque de estacionamento subterr��neo. V��o ser comparadas v��rias simula����es com situa����es diferentes em termos de condi����es de fronteira, obstru����es ao escoamento, etc., por forma a tirar conclus��es sobre o comportamento do parque numa situa����o de emerg��ncia, ou seja, num inc��ndio. Este comportamento vai ter em conta a efici��ncia de evacua����o dos gases libertados, as temperaturas no parque que permitem verificar onde est��o localizados os gases mais quentes e os campos de velocidade do ar que permitem uma visualiza����o do escoamento e at�� certo ponto a turbul��ncia do mesmo. No final pretende-se concluir por meio de compara����o com outros documentos consultados, a ���confiabilidade��� do software usado (FDS-Fire Dynamics Simulator) e adicionalmente tirar conclus��es sobre o projecto do parque, nomeadamente sobre a necessidade de introdu����o de altera����es.

Stability of extemporaneously prepared captopril oral liquid formulation for paediatric patients

Captopril, an inhibitor of angiotensin converting enzyme (ACE), is used to treat medical conditions like hypertension and heart failure, and it is usually administered in tablet form for adults. Since this dosage form is not recommended for infants and children up to 6 years, hospital pharmacies have to prepare liquid formulations for oral administration of captopril. Traditionally, concentration of captopril used in the formulations is 1mg/ml. The problem is that captopril is prone to oxidation, and its stability in solution is affected by pH, concentration of captopril, the presence of oxygen or metal ions. The influence of different formulation ingredients on the properties of physical and chemical stability of captopril in liquid preparations has been evaluated. Main of the study: to evaluate the stability of captopril for 30 days when formulated in a 1 mg/ml suspension adjuvanted with citric acid.

Chromatographic behaviour of monoclonal antibodies against wild-type amidase from Pseudomonasaeruginosa on immobilized metal chelates

The aim of this work was to devise a one-step purification procedure for monoclonal antibodies (MAbs) of IgG class by immobilized metal affinity chromatography (IMAC). Therefore, several stationary phases were prepared containing immobilized metal chelates in order to study the chromatographic behaviour of MAbs against wild-type amidase from Pseudomonas aeruginosa. Such MAbs adsorbed to Cu(II), Ni(II), Zn(II) and Co(II)-IDA agarose columns. The increase in ligand concentration and the use of longer spacer arms and higher pH values resulted in higher adsorption of MAbs into immobilized metal chelates. The dynamic binding capacity and the maximum binding capacity were 1.33 +/- 0.015 and 3.214 +/- 0.021 mg IgG/mL of sedimented commercial matrix, respectively. A K(D) of 4.53 x 10(-7) M was obtained from batch isotherm measurements. The combination of tailor-made stationary phases of IMAC and the correct selection of adsorption conditions permitted a one-step purification procedure to be devised for MAbs of IgG class. Culture supernatants containing MAbs were purified by IMAC on commercial-Zn(II) and EPI-30-IDA-Zn(II) Sepharose 6B columns and by affinity chromatography on Protein A-Sepharose CL-4B. This MAb preparation revealed on SDS-PAGE two protein bands with M(r) of 50 and 22 kDa corresponding to the heavy and light chains, respectively. Copyright (C) 2011 John Wiley & Sons, Ltd.