Health & Environmental Research Online (HERO)


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2,225 References Were Found:

Technical Report
Technical Report

Application of the criteria for classification of existing chemicals as dangerous for the environment

Authors: Knacker, T; Schallnass H-J; Klaschka, U; Ahlers, J (1995) (179-187). (BIOSIS/96/04508). HERO ID: 1628447

[Less] BIOSIS COPYRIGHT: BIOL ABS. The criteria for classification and labelling of substances as "dangerous . . . [More] BIOSIS COPYRIGHT: BIOL ABS. The criteria for classification and labelling of substances as "dangerous for the environment" agreed upon within the European Union (EU) were applied to two sets of existing chemicals. One set (sample A) consisted of 41 randomly selected compounds listed in the European Inventory of Existing Chemical Substances (EINECS). The other set (sample B) comprised 115 substances listed in Annex I of Directive 67/548 which were classified by the EU Working Group on Classification and Labelling of Existing Chemicals. The aquatic toxicity (fish mortality, Daphnia immobilisation, algal growth inhibition), ready biodegradability and n-octanol/water partition coefficient were measured for sample A by one and the same laboratory. For sample B, the available ecotoxicological data originated from many different sources and therefore was rather heterogeneous. In both samples, algal toxicity was the most sensitive effect parameter for most substances. Furthermore, it was found that, clas

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

An Investigation of Clustering as a Tool in Quantitative Structure-Activity Relationships (QSARS)

Authors: Nouwen, J; Hansen, B (1995) SAR and QSAR in Environmental Research 4:1-10. HERO ID: 4240998

[Less] Abstract By means of clustering, one is able to manage large databases easily. Clustering according . . . [More] Abstract By means of clustering, one is able to manage large databases easily. Clustering according to structure similarity distinguished the several chemical classes that were present in our training set. All the clusters showed correlation of log WS with log K ( OW ) and melting point, except EINECS-cluster 1. This cluster contains only chemicals with melting points below room temperature, resulting in a log WS-log K( OW ), relationship. The observed weak correlation for this cluster is probably due to the insufficient number of available screens. Such a limited amount of screens allows relatively very different chemicals to share the same cluster. Using statistical criteria, our approach resulted in three QSARs with reasonably good predictive capabilities, originating from clusters 1639, 3472, and 5830. The models resulting from the smaller clusters 6873, 8154, and 16424 are characterised by high correlation coefficients which describe the cluster itself very well but, due to our stringent bootstrap criterion, they are close to randomness. Clusters 6815 and 18083 showed rather low correlations. The models originating from clusters 1639, 3472, and 5830 proved their usefulness by external validation. The log WS-values calculated with our QSARs agreed within 1 log-unit to these reported in the literature.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

EFFECT OF UREA ON MICELLE FORMATION OF FLUOROCARBON SURFACTANTS

Authors: Asakawa, T; Hashikawa, M; Amada, K; Miyagishi, S (1995) HERO ID: 3860182

[Less] The effect of urea on micelle formation of fluorocarbon surfactants was investigated by measuring conductivity . . . [More] The effect of urea on micelle formation of fluorocarbon surfactants was investigated by measuring conductivity cmc and fluorescence intensity of probes (1-anilinonaphthalene-8-sulfonate, auramine, and pyrene). We examined various fluorocarbon surfactants which consist of different ionic head groups, i.e., lithium perfluorononanoate (LiPFN), diethylammonium perfluorononanoate (DEAPFN), lithium perfluorooctanesulfonate (LiFOS), and 1H-1H,2H,2H-perfluorodecyl sulfate (LiHFDeS). Significant differences do exist between fluorocarbon and hydrocarbon surfactants; the cmc's of the fluorocarbons slightly decreased with the addition of urea, while those of the hydrocarbons increased as reported previously. The slight decreases in cmc's of fluorocarbon surfactants were confirmed by comparison with LiDS and LiHFDeS which contain the same ionic head group. The counterion dissociation degree of micelles always increased with the addition of urea. The micropolarities of fluorocarbon micelles were almost identical with the polarity of water, and were independent of urea concentration. The microviscosities of DEAPFN micelles decreased with urea concentration. These results suggest the significant differences in micellar characteristics between fluorocarbon and hydrocarbon surfactants.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

CRITICAL DEMICELLIZATION CONCENTRATION OF DIETHYLAMMONIUM PERFLUORONONANOATE AND DIETHYLAMMONIUM TETRADECYL SULFATE MIXTURE IN AQUEOUS-SOLUTION

Authors: Asakawa, T; Shiraishi, T; Sunazaki, S; Miyagishi, S (1995) HERO ID: 3860184

[Less] The micellar pseudophase diagram of diethylammonium perfluorononanoate (DEAPFN) and diethylammonium . . . [More] The micellar pseudophase diagram of diethylammonium perfluorononanoate (DEAPFN) and diethylammonium tetradecyl sulfate (DEATS) was determined by both conductivity and fluorescence probe methods. The conductivity measurements gave unusually low dissociation degrees of counter ion for DEAPFN-rich regions in contrast to those for DEATS-rich region. The micelles in a DEAPFN-rich region have high microviscosities, suggesting a micellar growth. The existence of the second cmc indicated the presence of two types of mixed micelles, but the mutual solubility of fluorocarbon and hydrocarbon surfactants in micellar pseudophase showed significant differences between DEAPFN-DEATS and LiPFN-LiTS systems. Third inflection points on both conductivity and fluorescence intensity curves were observed for DEAPFN-DEATS system. This suggests the presence of a critical demicellization concentration (CDC).

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

STRUCTURE OF THE ISOTROPIC, NEMATIC, AND LAMELLAR PHASE OF A SOLUTION OF TETRAMETHYLAMMONIUM PERFLUORONONANOATE IN D2O

Authors: Froba, G; Kalus, J (1995) HERO ID: 3860191

[Less] A 30% by weight solution of tetramethylammonium perfluorononanoate in D2O (TMAHFN; C8F17COON-(CH3)(4)) . . . [More] A 30% by weight solution of tetramethylammonium perfluorononanoate in D2O (TMAHFN; C8F17COON-(CH3)(4)) is in a lamellar state below 33 degrees C. In this state the repeat distance and the thickness of the perfluoronated part of the micellar lamellae are around 7.11 and 2.14 nm, respectively, In the presence of a strong magnetic field of 2.0 T a slow reduction of the sample temperature from 40 degrees C (isotropic phase) via 34 degrees C (nematic phase) down to 25 degrees C gives a strong alignment of the nematic and lamellar liquid crystalline phases. By small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) experiments, an order parameter, the mean scattering length density across the lamellae, the structure factor related to the one-dimensionality of the lamellar phase, and information about the perforation of the lamellae could be extracted. A model taking into account all these effects quantitatively describes the experimental scattering intensity distribution in reciprocal space (($) over right arrow Q space) accessible in our experimental setup. Furthermore, for the nematic phase we can extract detailed data on the anisotropic correlation between neighboring discotic micelles. The scattering intensity distribution of the isotropic phase can be described quite satisfactorily again assuming disklike micelles, where the perfluoronated part of the micelle has a thickness of 2.4 nm and a radius of about 3.0 nm.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

SOLUTION PROPERTIES OF ALKALI METAL PERFLUOROALKANOATES

Authors: Muzzalupo, R; Ranieri, GA; Lamesa, C (1995) HERO ID: 3860203

[Less] Solution properties of perfluorononanoic acid and of its alkali metal salts, volumetric, colligative, . . . [More] Solution properties of perfluorononanoic acid and of its alkali metal salts, volumetric, colligative, emf and electrical conductance experiments and were supported by studies on phase equilibria, performed in close proximity to the CMC. Thermodynamics of micelle formation has been analysed both in terms of a charged-phase model and according to an isodesmic multiple equilibrium approach for counterion effect on micellization and for the cooperativity of micellarization association, respectively.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Implications of council regulation 793/93 on the evaluation and control of existing substances

Author: Mccutcheon, P (1994) Annali dell'Istituto superiore di sanità 30:367-372. HERO ID: 4240999

[Less] The European Union (EU) programme on existing substances makes provision for the delivery by industry . . . [More] The European Union (EU) programme on existing substances makes provision for the delivery by industry of data on substances produced or imported above certain quantities which will be used by the Commission to facilitate selection of priority lists of substances for which risk assessments will be carried out. The substances comprise three subsets of the existing substances listed in the European Inventory of Existing Commercial Chemical Substances (EINECS) according to the respective deadlines for delivery of the data. The risk assessments are performed by the member states according to a commission regulation 1488/94 supported by guidance documents, may require further data delivery or performance of tests by industry and must conclude that the substance is either of no concern, of concern and risk reduction measures are appropriate, or require further data or testing to arrive at one of the other conclusions. The EU programme on existing chemicals is coordinated with the related OECD programme which will allow chemicals evaluated under regulation 793/93 to constitute an EU contribution to OECD and to largely allow the community to avoid investing unnecessary resources in substances being evaluated by non-EC countries.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

COMPLEX-FORMATION IN BINARY-SOLUTIONS OF ANIONIC SURFACTANTS WITH POLYSACCHARIDES

Authors: Alekseeva, YI; Simakova, GA; Soloveva, TS (1994) HERO ID: 3860143

[Less] In water solutions of mixtures of polysaccharides with potassium oleate or ammonium salt of perfluoropelargonic . . . [More] In water solutions of mixtures of polysaccharides with potassium oleate or ammonium salt of perfluoropelargonic acid, interaction of the components takes place and is accompanied by complex formation. The establishment of adsorption equilibrium in such cases is controlled by diffusion and is connected with the relaxation processes of the reorientation of surfactant-polysaccharide complexes.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

FURTHER INVESTIGATION OF THE PREPARATION PROCESS OF POLY(P-PHENYLENEVINYLENE) LANGMUIR-BLODGETT-FILMS

Authors: Wu, AP; Yokoyama, S; Watanabe, S; Kakimoto, M; Imai, Y; Araki, T; Iriyama, K (1994) HERO ID: 3860154

[Less] The Langmuir-Blodgett (LB) films of conducting poly(p-phenylenevinylene) (PPV) were prepared by thermal . . . [More] The Langmuir-Blodgett (LB) films of conducting poly(p-phenylenevinylene) (PPV) were prepared by thermal treatment (250-degrees-C, 1 Torr) of the LB film of the PPV precursor, amphiphilic poly(p-xylylene-alpha-diethylsulphonium) salt with perfluorononanoate counterion. The formation of the pi-conjugated PPV structure varied with the thermal annealing time and was studied by means of UV spectroscopy. The elimination of the sulphide and fluorinated fatty acid during the thermal treatment was determined quantitatively by X-ray photoelectron spectroscopy. Both results indicated that extension of the pi-conjugated structure could be realized and conversion from the PPV precursor to PPV could be completed within 10 min under these conditions. Furthermore, transmission electron microscopy examination revealed a gradual change in the surface image from heterogeneous to homogeneous during the thermal treatment, which indicated that a smooth surface of the PPV LB film was gradually formed by the thermal conversion.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

DISTINCTIVE BEHAVIOR OF THE ESR CORRELATION TIMES OF DOXYL SPIN PROBES IN MIXED MICELLAR SOLUTIONS OF HYDROCARBON AND FLUOROCARBON SURFACTANTS

Authors: Kamogawa, K; Tajima, K (1993) The Journal of Physical Chemistry 97:9506-9512. HERO ID: 3767606

[Less] The ESR correlation time tau(c) of DOXYL stearic acid nitroxide spin probes was measured to clarify . . . [More] The ESR correlation time tau(c) of DOXYL stearic acid nitroxide spin probes was measured to clarify the micellar miscibility of perfluorocarbon and hydrocarbon surfactants in an aqueous solution. In one group, named type I micelles, tau(c) was found to increase on mixing at first and then decrease at a particular composition. An invariant region separated such a change in tau(c) for another group, named type II micelles. The two types were consistent with the freely miscible, and the partially immiscible, micelles following Shinoda's theory (J. Phys. Chem. 1980, 84, 365-369). Sodium perfluorooctanoate and sodium dodecyl sulfate at 45-100 mM concentration formed type I micelles. The tau(c) profile converted to type II behavior in the presence of 0.1 M NaCl. Ammonium perfluorononanoate and ammonium dodecyl sulfate also exhibited type II behavior at 25-degrees-C, accompanied by a discontinuous jump in tau(c) at X(HC) = 0.65. The invariant region disappeared at 50-degrees-C leading to type I profile, as predicted theoretically. Prior to this conversion, the jump of tau(c) disappeared at 40-degrees-C. In an Arrhenius plot, the logarithm Of tau(c)-1 for X(HC) = 0.7 and 1 both gave parallel, monotonic decreases with T-1, though that for X(HC) = 0. 5 coincided first with the line for X(HC) = 0. 7 but appeared a transition at 40-degrees-C to the X(HC) = 1 line. These characteristics were discussed in relation to standard 2-micelle models and a new 1-micelle model.