A preliminary study of gross alpha/beta activity concentrations in drinking waters from Albania

A pilot study involving screening measurements of gross alpha/beta activity concentration in drinking water was performed in 12 cities with the highest population density in Albania. The aim of this study was to develop a first insight regarding the radiological quality of drinking and bottled water supplies. The tap and bottled water samples investigated are acceptable for consumption, complying with the WHO recommendations for drinking water. The average gross alpha and beta activity concentrations were \( 36_{ - 18}^{ + 37} \) and \( 269_{ - 150}^{ + 337} \)  mBq/L, respectively in tap waters. While for bottled water the gross alpha and beta activities were respectively \( 39_{ - 23}^{ + 55} \) and \( 220_{ - 132}^{ + 336} \)  mBq/L. The data obtained can provide information for authorities regarding the quality of drinking water and a baseline for future contaminations.     

Effects of Cyclodextrins on Dodecane Biodegradation

Bioremediation of non-chlorinated hydrocarbon-polluted soils is mainly affectedby low bioavailability, due to hydrophobicity of these xenobiotics. In fact, severalmicroorganisms can use hydrocarbons as energy and carbon sources, but theirdegradative activity takes place into the aqueous phase of the soil, where just tracesof hydrocarbons are found because of their low water solubility. So, natural attenuationusually occurs in hydrocarbon-polluted soils, but this process is very slow. It has alreadybeen demonstrated that cyclodextrins increase hydrocarbon solubility and bioavailabilityand accelerate their biodegradation. In this work it was investigated if their efficacy onbiodegradation of a model hydrocarbon (dodecane) is affected by the kind (,-, - and hydroxypropyl--cyclodextrin) and the concentrationof cyclodextrin and by environmental factors such as temperature and composition ofthe microbial indigenous population. The results obtained show that all the testedfactors influence the biodegradation kinetics. The best results were obtained with-cyclodextrin at a concentration near to its water solubility limit; moreover,biodegradation rate increases with temperature and different microbial strains showdifferent degradative activity and metabolic behaviour.     

Diffusion properties of cyclodextrins in aqueous solution at 25°C

Diffusion, density, and viscosity data are collected for the systems -cyclodextrin and -cyclodextrin in water. Frictional coefficients were computed with the help of literature activity data and a qualitative discussion of their concentration dependence was attempted.     

Source apportionment of groundwater pollutants in Apulian agricultural sites using multivariate statistical analyses: case study of Foggia province

Background

Ground waters are an important resource of water supply for human health and activities. Groundwater uses and applications are often related to its composition, which is increasingly influenced by human activities.In fact the water quality of groundwater is affected by many factors including precipitation, surface runoff, groundwater flow, and the characteristics of the catchment area. During the years 2004-2007 the Agricultural and Food Authority of Apulia Region has implemented the project “Expansion of regional agro-meteorological network” in order to assess, monitor and manage of regional groundwater quality. The total wells monitored during this activity amounted to 473, and the water samples analyzed were 1021. This resulted in a huge and complex data matrix comprised of a large number of physical-chemical parameters, which are often difficult to interpret and draw meaningful conclusions. The application of different multivariate statistical techniques such as Cluster Analysis (CA), Principal Component Analysis (PCA), Absolute Principal Component Scores (APCS) for interpretation of the complex databases offers a better understanding of water quality in the study region.

Results

Form results obtained by Principal Component and Cluster Analysis applied to data set of Foggia province it’s evident that some sampling sites investigated show dissimilarities, mostly due to the location of the site, the land use and management techniques and groundwater overuse. By APCS method it’s been possible to identify three pollutant sources: Agricultural pollution 1 due to fertilizer applications, Agricultural pollution 2 due to microelements for agriculture and groundwater overuse and a third source that can be identified as soil run off and rock tracer mining.

Conclusions

Multivariate statistical methods represent a valid tool to understand complex nature of groundwater quality issues, determine priorities in the use of ground waters as irrigation water and suggest interactions between land use and irrigation water quality.

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Optimizing piezoelectric inkjet printing of silica sols for biosensor production

The effects of selected process conditions for the sol-gel encapsulation of laccase enzymatic extract, obtained from Coriolus hirsutus, were investigated. Screening trials were carried out to identify the parameters having the most pertinent effects on the encapsulation efficiency (EE) and the residual laccase activity. These parameters included water/silane molar ratio (r), HCl content and protein loading, for the pre-gel silica sol as well as the required time for gel drying and for aging, for the sol-gel process. The experimental findings indicated that a sol-gel drying time of over 6?h resulted in a complete loss of laccase catalytic activity, while an increase in the gel aging time led to an enhancement of the residual enzyme activity. Except for r, the investigated parameters demonstrated no significant effect on the EE of the sol-gel encapsulated enzymatic extract. Overall, the encapsulation of laccase extract in the sol-gel matrix resulted in an enhancement of its catalytic activity, where its highest residual activity (349%) was obtained with an r-value of 4, an HCl content of 4?µmol and a protein loading of 1?mg/mL, using 6 and 24?h of drying and aging times, respectively.

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Release of137Cs from anoxic lacustrine sediment measurement and formulation

Low level measurements of¹³⁷Cx in lacustrine sediment and its pore water are possible to activity as low as 10 mBq. From this data, the flux of¹³⁷Cs through the sediment and to the bottom water can be estimated. The value of the diffusion coefficient in the pore water follows from separate radiotracer experiments.     

Seasonal variation of activity ratios for natural uranium in surface waters

The uranium concentration, and²³⁴U/²³⁸U and²³⁵U/²³⁸U activity ratios were measured by alpha spectrometry of surface water from the neighbourhood of the uranium mines El Lobo and El Pedregal (Badajoz, Spain) before and after the rainy season. Changes were observed in all the three parameters studied. Leaching and dilution are the probable mechanisms for the seasonal changes in the concentration and in the²³⁴U/²³⁸U activity ratio as measured in open and dynamic systems (rivers).     

A highly selective colorimetric sulfide assay based on the inhibition of the peroxidase-like activity of copper nanoclusters

The authors report that sulfide ions are capable of inhibiting the peroxidase-like activity of copper nanoclusters (CuNCs). The catalytic activity of CuNCs toward the oxidation of the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine by H₂O₂ is remarkably decreased in the presence of sulfide. Based on this finding, a colorimetric assay was developed for the rapid determination of sulfide. Best operated at a wavelength of 652 nm, it has a 0.5 μM detection limit. The method is highly selective and has been successfully applied to the quantification of sulfide in environmental water samples.

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Graphical abstract The catalytic activity of CuNCs toward the oxidation of 3,3′,5,5′-tetramethylbenzidine by H₂O₂ is remarkably decreased in the presence of sulfide ions. This finding has been applied to design a method for colorimetric quantification of sulfide ions in environmental samples.

     

Transference Numbers of NaCl in Aqueous Mixtures with Organic Solvents of Moderate to Low Permittivities

Electromotive forces (emf) were measured in the transference cells: AgAgCl- Nacl (m₂) in Z NaCl (m₁) in ZAgClAg and Na_xHg_1-xNaCl (m₁) in Z NaCl (m₂) in ZNa_xHg_1-x (where Na_xHg_1-x denotes a flowing Na–amalgam electrode and Z an aqueous-organic solvent mixture) at various molalities m ₂ > m₁ of NaCl in Z = (ethylene glycol + water), (acetonitrile + water) and (1,4-dioxane + water), with mass fractions of the organic components 0.8. The transference number of Na⁺ in (ethylene glycol + water) and (1,4-dioxane + water) varies little with respect to that in pure water medium, whereas in (acetonitrile + water) it increases remarkably with increasing proportion of acetonitrile so as to approach equitransference, behavior similar to that previously found in (methanol + water) and in (ethanol + water). At acetonitrile mass fraction 0.6 NaCl is sufficiently close to equitransference to emerge as a useful salt bridge, nearly at the same level as the popular aqueous KCl.     

Interaction of aminoquinolines with unsaturated carboxylic acids. 1. Synthesis of N-quinolyl-β-alanines and their biological activity

N-Quinolyl--alanines, and -methyl- and-methyl-N-quinolyl--alanines were prepared by reaction of aminoquinolines and acrylic, methacrylic, and crotonic acids. The corresponding hydrazides and benzylidenehydrazides were obtained. 4-Aminoquinoline with unsaturated acids in water gave betaines. The biological activity of sodium salts of -alanines was investigated.Kaunas University of Technology, Kaunas LT-3028, Lithuania; Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 504–511, April, 2000.     

The influence of the water content on the adsorption properties of γ-Al2O3

Summary One of the most important parameters which decide the peaks resolution in HPLC with the nonmodified adsorbents, is the amount of water which is present on the adsorbent surface. This article tries to show that the change in the adsorption properties of -Al₂O₃ is dependent on the amount of adsorbed water. These changes are shown with the help of adsorption isotherms, isosteric heats of adsorption and adsorption energy distributions. The data is analysed on the bases of Jovanovic equations. It was also found that a relationship exists between the Brockman activity scale and the adsorption isotherm of water on -Al₂O₃.     

Thermodynamics of the Solubility of Water in 1-Hexanol, 1-Octanol, 1-Decanol, and Cyclohexanol

Summary. The solubility of water in 1-hexanol, 1-octanol, 1-decanol, and cyclohexanol was determined as a function of water activity by the isopiestic method at 298.2K. The solubility of water in the alcohol was expressed by a Setchenov type of equation and the correlation coefficients were related to the virial coefficients of the McMillan-Mayer theory of solution. From the solubility data both the activities and the osmotic coefficients of the alcohols were calculated. The Henrys law constants for the solubility of water in the alcohols are given. They depend linearly on the Gibbs energy of hydration. The excess Gibbs energy of mixing of water and alcohols is positive as a consequence of the strong intermolecular interactions of the two pure components of the mixture.     

Study of amorphous Ni-La-B/g-Al2O3 catalysts for the production of hydrogen peroxide from carbon monoxide, water and oxygen

Summary Novel amorphous Ni-La-B/-Al₂O₃ catalysts have been developed for the production of hydrogen peroxide from carbon monoxide, water and oxygen. The experimental investigation confirmed that the catalyst dried at 120ºC in air shows the best initial activity. The deactivation of amorphous Ni-La-B/-Al₂O₃ catalysts was also studied.     

Effects of Some Hydrotropic Agents on the Formation of Indomethacin/β-Cyclodextrin Inclusion Compounds

The influence of the water structure promoters, mannitol and sucrose, on the indomethacin/-cyclodextrin inclusion process at different pH values was evaluated using the phase solubility method and circular dichroism spectroscopy. The effect of mannitol and sucrose on the total solubilizing activity of -cyclodextrin as well as on the stabilization of the complex was moderate, and depended strongly on the pH value of the medium. The most pronounced effect on the association constant of the indomethacin inclusion compound was observed in KCl/HCl buffer of pH 1.6, because mannitol and sucrose, in the absence of -cyclodextrin, approximately double the indomethacin solubility so that the constant value decreases. On the other hand, a very strong complex formation between indomethacin and -cyclodextrin was observed in acid medium (KCl/HCl buffer, pH = 1.6), a fact not much discussed in the literature. The apparent association constant of the inclusion compound formed in the absence of mannitol or sucrose was found to be of the same order of magnitude as for the complex formed at pH 6.8. Changes in the optical activity of the indomethacin/-cyclodextrin inclusion complex were registered in the presence of sucrose, which interacts more strongly than mannitol with water molecules, and could probably adhere to the surface of the inclusion complex, thus changing its configuration and environment.     

The nature of colloidal platinum in aqueous solution: features of catalytic reactions

The specific features of the catalytic reduction of methylviologen by dihydrogen in water in the presence of platinum colloids synthesized by various methods are studied. The colloids prepared by the radiation-chemical reduction of PtCl₄ ^2– in the presence of polyacrylate or polyphosphate as stabilizers and colloids prepared by the reduction with dihydrogen efficiently catalyze the reaction. The citrate colloids synthesized by the reduction of PtCl₆ ^2– with citric acid are characterized by a prolonged induction period after which these colloids also gain the catalytic activity. We assume that the citrate platinum colloids are giant clusters with the close-packed metal core containing the magic number of platinum atoms (Pt₅₆₁), which are coordinated by the ligand molecules blocking the surface of the metal particle. In the presence of H₂, the ligand molecules are decomposed or removed from the surface, which is accompanied by the appearance of the catalytic activity.     

Stabilities in water and transfer activity coefficients from water to nonaqueous solvents of 15-crown-5 and 16-crown-5-metal ion complexes

Stability constants of 1 : 1 16-crown-5 (16C5)-metal ion complexes were determined in water at 25°C by conductometry and potentiometry with ion-selective electrodes. The selectivity sequences of 16C5 in water for univalent and bivalent metal ions are Ag⁺ > Na⁺ Tl⁺ > K⁺ and Sr²⁺ > Ba²⁺ Pb²⁺, respectively. The stability of a given 16C5-metal ion complex in water is much lower than might be expected on the basis of the solvation power (i.e. relative solubility of the metal ion) of water for the metal ion. The same tendency is observed for the cases of 15-crown-5 (15C5) -metal ion complexes. Transfer activity coefficients () of 15C5 and 16C5 for tetradecane (TD)/water, TD/methanol, TD/acetonitrile, and propylene carbonate/water systems were determined at 25°C. From these data, contributions of a methylene group and an ether oxygen atom to the log value of a crown ether were then obtained. The values from water to acetonitrile, propylene carbonate, and methanol of 15C5- and 16C5-univalent metal ion complexes were calculated, s, M⁺, and L being a solvent, a univalent metal ion, and a crown ether, respectively. The log value is greater than the corresponding log value. The log values are negative. This indicates that, although the M^- ions are more soluble in water than in the nonaqueous solvents, when the crown ether forms a complex with the M⁺ ion, the complex becomes more soluble in the nonaqueous solvents than in water, compared with the free crown ether. It was concluded from this finding that the unexpectedly low stability of the crown ether-M⁺ complex in water is attributed to strong hydrogen bonding between ether oxygen atoms of the free crown ether and water.     

The inclusion of rhodium(II)α-methyl-cinnamate in β-cyclodextrin

The preparation and characterization of the 1:1 inclusion compound of rhodium(II) -methyl cinnamate in -cyclodextrin is reported. Evidence of inclusion was obtained from X-ray powder diffraction results, Raman, IR and UV-Vis spectroscopic studies and thermal analysis. Given the potential antitumor activity of the rhodium(II) carboxylate and its virtual insolubility in water, its inclusion in -cyclodextrin opens the possibility for its transference to the aqueous phase.     

The catalatic and peroxidatic activity of irradiated dilute aqueous solutions of catalase

The influence of -irradiation on both catalatic and peroxidatic activity of bovine liver catalase in dilute aqueous solutions has been studied. An attempt to find correlations between radiation-induced conformational changes of the enzyme molecule and the loss of enzymatic activity has been undertaken. The role of radicals of water radiolysis on the radiosensitivity of the enzyme and on post-radiation recovery of enzyme activity has been also investigated.     

Chromatographic retention data of N-alkylamides of benzomorpholine-2-carboxylic acid in the study of structure-activity relationships

Summary The adrenolytic activity of N-alkylamides of benzomorpholine-2-carboxylic acid was correlated to their log k and R_M values determined by reversed-phase liquid chromatography and thin-layer chromatography. Mixtures of water with several organic modifiers were used as the mobile phase.