Development and validation of passive samplers for atmospheric monitoring of SO2, NO2, O3 and H2S in tropical areas

Traditionally the monitoring of atmospheric pollutants is aimed at managing accidents and short-term actions for the protection of human health on local and regional scales. These monitoring networks required continuous measurements with high time resolution, involving costly equipment, operation and maintenance. More recent simulations with mathematical models and scenario-building on regional, continental and global scales, as well as studies of environmental personal exposure are demanding three main types of monitoring design, where need for special resolution surpasses the one of temporal resolution: remote places, where no electric power nor trained human resources are available; validation of dispersion simulation by mathematical modeling on regional to larger scales; indoor measurements where people are acting under noise restriction such as residences, school and hospitals. To meet these demands environmental passive samplers for atmospheric gaseous pollutants have been developed and applied for different situations and environments of Brazil. Passive samplers were developed based on molecular diffusion of gas through a static layer of air with fixed filters impregnated with a specific solution for SO₂, NO₂, O₃ and H₂S and used in the following situations: in remote forest area, urban areas with different characteristics - near the sea, with clean ocean air masses coming in and in areas under direct industrial influence. The passive samplers showed good performance when exposed to different types of areas and during different periods: accuracy of measurements, based on standard deviation, were within the recommended limit by the European Union of ± 25% for this type of device and precision below the maximum of 20% cited in the literature, with variation of 2.0 to 16% in the case of these work. The passive devices were able of measuring concentrations very low as those found in the Amazon region (0.58 ± 0.05 µg m^− 3 SO₂ and 1.10 ± 0.07 µg m^− 3 NO₂) and higher concentrations in industrial areas (20.0 ± 1.3 µg m^− 3 SO₂ e 21.0 ± 1.3 µg m^− 3 NO₂).     

Proficiency testing in analytical chemistry, microbiology, and laboratory medicine – working group discussions on current status, problems, and future directions

Working group (WG) discussions on proficiency testing (PT) held at the joint Eurachem/ EQALM workshop, Borås, Sweden, 24–26 September 2000 are summarized. The discussions focused on aspects of PT and accreditation (WG 1), general aspects of PT in analytical chemistry (WG 2), microbiology (WG 3), and laboratory medicine (WG 4), incorporation of measurement uncertainty into PT schemes (WG 5), international harmonization of PT schemes (WG 6), and the role of PT in the international structure of chemical measurement (WG 7). Current status, problems and future directions are identified. Each WG contained a majority of participants experienced in the subject being covered by that WG, and a few participants with different expertise. This was done to promote cross-fertilization of ideas between sectors, a key objective of the workshop. The WG issues reflected the content of the keynote lectures and some issues were covered from different perspectives by more than one group.     

On the Radical Nature of Iron‐Catalyzed Cross‐Coupling Reactions

The radical nature of iron‐catalyzed cross‐coupling between Grignard reagents and alkyl halides has been studied by using a combination of competitive kinetic experiments and DFT calculations. In contrast to the corresponding coupling with aryl halides, which commences through a classical two‐electron oxidative addition/reductive elimination sequence, the presented data suggest that alkyl halides react through an atom‐transfer‐initiated radical pathway. Furthermore, a general iodine‐based quenching methodology was developed to enable the determination of highly accurate concentrations of Grignard reagents, a capability that facilitates and increases the information output of kinetic investigations based on these substrates.     

Cycloaddition of nitrones and α,β-unsaturated sugar lactones

It was found that 1,3-cycloaddition of nitrones 1–3 to α,β-unsaturated sugar carbonyl compounds 4–8 proceeds regiospecifically to give mixtures of stereoisomers. Nitrones 1–3 entered compounds 4–8 in trans-relation to the existing ring substituent.     

Die IR-Spektren einiger Arsenat-Halogen-Apatite

The infrared spectra of orthoarsenates with apatite structure, of the formulaM ₅(AsO₄)₃ X (M=Ca, Sr, Ba, Pb andX=F, Cl,Br) are measured and interpreted on the basis of a site-symmetry analysis. The influence of the different cations on the internal vibrations of the AsO₃ ⁴-ions is discussed.

     

Aggregation of fuzzy preference relations to multicriteria decision making

Weighted aggregation of fuzzy preference relations on the set of alternatives by several criteria in decision-making problems is considered. Pairwise comparisons with respect to importance of the criteria are given in fuzzy preference relation as well. The aggregation procedure uses the composition between each two relations of the alternatives. The membership function of the newly constructed fuzzy preference relation includes t-norms and t-conorms to take into account the relation between the criteria importance. Properties of the composition and new relation, giving a possibility to make a consistent choice or to rank the alternatives, are proved. An illustrative numerical study and comparative examples are presented.     

The influence of structural changes of the N-substituent on liquid crystalline behaviour of ester imides

Several new ester imide derivatives with different N-substituents in the imide ring were synthesized and their mesogenic properties investigated by thermal analysis, optical microscopy and X-ray diffraction. All the esters of N-4-[(4'-decyloxybiphenyl-4-yl)oxycarbonyl]phthalimideacetic acid and aliphatic alcohols exhibited monolayer SmA and SmC phases. In addition, for the ethyl and propyl esters a monotropic hexatic (F or I) phase was observed. The introduction of additional substituents at the carbon atom in the methylenemethoxycarbonyl group (in the vicinity of the nitrogen atom) substantially influenced liquid crystalline properties: the compounds with a flexible chain exhibited monotropic SmA-SmB dimorphism, but liquid crystalline properties vanished for the substituent containing the more rigid phenyl ring.     

Is there a Trade-Off between Quality and Productivity? The Case of Diagnostic Technologies in Portugal

The purpose of this paper is twofold: first, we compute quality-adjusted measures of productivity change for the three most important diagnostic technologies (i.e., the Computerised Tomography Scan, Electrocardiogram and Echocardiogram) in the major Portuguese hospitals. We use the Malmquist–Luenberger index, which allows to measure productivity growth while controlling for the quality of the production. Second, using non-parametric tests, we analyse whether the implementation of the Prospective Payment System may have had a positive impact on the movements of productivity over time. The results show that the PPS has helped hospitals to use these tools more efficiently and to improve their effectiveness.     

Linear and cyclic aminomethanephosphonic acid esters derived from benzaldehyde derivatives, 3‐aminopropanol,and diethyl phosphite

A series of four diethyl {[(3‐hydroxy‐ propyl)amino](aryl)methyl}phosphonates have been prepared and characterized. In one case, the phosphonate was transformed to a seven‐membered 1,4,2‐ oxazaphosphepane heterocycle through a one‐pot intramolecular esterification. The analogous reaction with formaldehyde gave the six‐membered diethyl (1,3‐oxazinan‐3‐ylmethyl)phosphonate, which could be transformed in a posterior reaction to the corresponding aminomethanephosphonic acid. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:75–80, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20178