bluuebunny/crossref_metadata_2025 huggingface dataset:
Vereinfachtes Berechnungsverfahren nach DIN 1053‐100
Authors: Schlundt Andreas
Published: February 2007

Das vereinfachte Berechnungsverfahren konnte in DIN 1053‐100 in seiner Einfachheit erhalten werden. Mauerwerk kann damit auch nach dem Teilsicherheitskonzept wie bisher mit dem globalen Sicherheitskonzept nach DIN 1053‐1 in der Praxis schnell und mit geringem Aufwand nachgewiesen werden, ohne daß eine aufwendige Schnittgrößenermittlung mit allen maßgebenden Lastfallkombinationen erforderlich wird. Die Anwendungsvoraussetzungen für die vereinfachte Bemessung sind die gleichen wie bisher. Bei der Umstellung auf das Teilsicherheitskonzept wurden die Nachweise modifiziert und auf Kräfte als nachzuweisende Größe anstelle der bisher üblichen Spannungen umgestellt. Auf der Grundlage ausführlicher Parameterstudien und theoretischer Untersuchungen konnte zudem eine Anpassung an den heutigen Stand der Technik vorgenommen werden. Der Beitrag stellt das vereinfachte Berechnungsverfahren insgesamt vor und informiert über neu aufgenommene Regelungen und deren Grundlagen.
Nachweis von Kellerwänden nach DIN 1053‐100
Authors: Vassilev Todor , Jäger Wolfram
Published: February 2007

Mit der Einführung des neuen Sicherheitskonzeptes ist auch der vereinfachte Nachweis für Kellerwände konsequent umgestellt worden. Der Hintergrund der Grenzlastkriterien und die Zusammenhänge werden erläutert. Es folgen Analysen und Hinweise zu statisch‐konstruktiven Maßnahmen, wenn in bestimmten Situationen ein Nachweis nicht geführt werden kann. Zur Frage des Erddruckes wird Stellung genommen, und die bisherigen Grundlagen dazu werden in Erinnerung gebracht.
Seniorengerechtes Bauen als Herausforderung für die Sozial‐ und Wohnungspolitik in der Bundesrepublik Deutschland
Authors: Rast Ronald
Published: February 2007

Insgesamt 23 Verbände der Bau‐ und Wohnungswirtschaft sowie die IG BAU haben sich seit Ende 2005 in der Aktion “Impulse für den Wohnungsbau” zusammengeschlossen. Gemeinsam haben sie ein Positionspapier unter dem Titel “Seniorengerechtes Bauen als Herausforderung für die Sozial‐ und Wohnungspolitik in der Bundesrepublik Deutschland” herausgegeben.
Passivhäuser aus Kalksandstein – energetisch hochwertig
Authors: Schulze Darup Burkhard
Published: February 2007

Experten und Branchenkenner schätzen, daß im Jahr 2010 etwa jedes fünfte Haus in Passivhausbauweise entstehen wird. Zwei Faktoren spielen dabei eine wichtige Rolle: Zum einen wird der Bau energiesparender Gebäude gefördert, zum anderen steigen die Heizkosten und somit die Unterhaltskosten von Jahr zu Jahr weiter an. Ferner ist davon auszugehen, daß die Energiekostensteigerungen in zum Teil schmerzhaften Sprüngen stattfinden werden. Die beste Versicherung dagegen ist frühzeitiges Investieren in Energieeffizienz und regenerative Energieversorgung – zum Beispiel durch den Bau eines massiven Passivhauses aus Kalksandstein.
Metabolic and cardiovascular risk factors in subjects with impaired fasting glucose: the 100 versus 110 mg/dL threshold
Authors: Andreozzi Francesco , Succurro Elena , Mancuso Maria Rosaria , Perticone Maria , Sciacqua Angela , Perticone Francesco , Sesti Giorgio
Published: February 2007

Background

In 2003, the American Diabetes Association (ADA) established a new cutoff for impaired fasting glucose (IFG) by reducing it from 110 to 100 mg/dL. This change was challenged as to its appropriateness. A few studies have examined the impact of the ADA2003 threshold of IFG on metabolic and cardiovascular risk factors.

Methods

We examined whether metabolic and cardiovascular risk factors, including inflammatory biomarkers, differ in subjects with the new ADA2003 threshold of IFG (IGF100) as compared with subjects with the old ADA1997 threshold of IFG (IFG110) in a cohort of 946 nondiabetic Italian Caucasians (fasting plasma glucose < 126 mg/dL).

Results

As compared with normal fasting glucose (NFG), subjects with IFG100 and IFG110 had higher body mass index (BMI), waist circumference, total and low density lipoprotein (LDL) cholesterol, triglyceride, fasting and 2‐h post‐challenge plasma glucose, fasting insulin, systolic blood pressure, and lower levels of high density lipoprotein (HDL) and insulin‐like growth factor I (IGF‐I). In a logistic regression analysis with adjustment for age and gender, IFG110 was associated with higher risk of post‐challenge glucose intolerance as compared with IFG100. As compared with IFG100, subjects with IFG110 have significantly lower levels of circulating IGF‐I. As compared with NFG, IFG110, but not IFG100, showed a significant association with increased levels of inflammatory markers including white blood cell count (WBCC), and C‐reactive protein (CRP). Both CRP and WBCC were correlated with 2‐h plasma glucose but not with fasting plasma glucose (FPG).

Conclusions

The data show that IFG110 is associated with a worse metabolic and cardiovascular risk profile as compared with IFG100. Copyright © 2007 John Wiley & Sons, Ltd.
BAX contributes to Doppel‐induced apoptosis of prion‐protein–deficient Purkinje cells
Authors: Heitz S. , Lutz Y. , Rodeau J.‐L. , Zanjani H. , Gautheron V. , Bombarde G. , Richard F. , Fuchs J.‐P. , Vogel M. W. , Mariani J. , Bailly Y.
Published: February 2007

Research efforts to deduce the function of the prion protein (PrPc) in knock‐out mouse mutants have revealed that large deletions in the PrPc genome result in the ectopic neuronal expression of the prion‐like protein Doppel (Dpl). In our analysis of one such line of mutant mice, Ngsk Prnp0/0 (NP0/0), we demonstrate that the ectopic expression of Dpl in brain neurons induces significant levels of cerebellar Purkinje cell (PC) death as early as six months after birth. To investigate the involvement of the mitochondrial proapoptotic factor BAX in the Dpl‐induced apoptosis of PCs, we have analyzed the progression of PC death in aging NP0/0:Bax−/− double knockout mutants. Quantitative analysis of cell numbers showed that significantly more PCs survived in NP0/0:Bax−/− double mutants than in the NP0/0:Bax+/+ mutants. However, PC numbers were not restored to wildtype levels or to the increased number of PCs observed in Bax−/− mutants. The partial rescue of NP0/0 PCs suggests that the ectopic expression of Dpl induces both BAX‐dependent and BAX‐independent pathways of cell death. The activation of glial cells that is shown to be associated topographically with Dpl‐induced PC death in the NP0/0:Bax+/+ mutants is abolished by the loss of Bax expression in the double mutant mice, suggesting that chronic inflammation is an indirect consequence of Dpl‐induced PC death. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007.
Consideration of optimum resistance values of MTJ in multilayered MRAM with various detection methods
Authors: Horiguchi Fumio , Yoda Hiroaki , Tahara Shuichi
Published: February 2007

For each case of current and voltage detection in series connections, and current and voltage in parallel connections in the multi‐layered structure of a magnetoresistive random access memory (MRAM) cell having two serially connected magnetic tunnel junction (MTJ) layers, first, we demonstrate the existence of an optimum value for the weighting coefficientkof the resistance, the voltage dependence, and the dependence on the magnetic resistance (MR) of the MTJ. Therefore, to optimize the signal margin in multiple layers, the ability to detect series connections with high sensitivity up to an MR ratio of 1 is demonstrated quantitatively. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(3): 42–48, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20265
Evaluation method of high‐permittivity materials in microwave region using coplanar waveguide
Authors: Tsuji Masatoshi , Tsuda Shotaro , Nishikawa Toshio , Wakino Kikuo , Kitazawa Toshihide
Published: February 2007

This paper proposes a novel evaluation method for dielectric characteristics of ceramic substrates made of high‐permittivity material, (Ba, Sr)TiO3(BST), in the microwave region. The dielectric characteristics are obtained accurately and simply by measuring S‐parameter and by full‐wave analysis for coplanar waveguide (CPW) composed on the substrate. Only the measurement ofS21response of the CPW is required for evaluation. The effective permittivity (εeff) and attenuation constant (α) are calculated from theS21data. Relative permittivity (εr) and tanδ of substrate material are estimated by relating the εeffand α quantitatively with their simulated values calculated by the Extended Spectral Domain Approach (ESDA) taking the thickness effect of the conductor into consideration. Three kinds of BST substrates with different Ba to Sr ratios were measured as test samples. The estimated εr's of Ba0.3Sr0.7TiO3, Ba0.5Sr0.5TiO3, and Ba0.7Sr0.3TiO3were 662, 1650, and 4450, respectively. These εr's decrease slightly as the frequency increases. The estimated errors for the εr's are estimated to be less than 0.3%. This method is useful for the evaluation even of a small variation of dielectric constant in high‐permittivity materials. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(3): 17–25, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20296
Complex‐valued multidirectional associative memory
Authors: Kobayashi Masaki , Yamazaki Haruaki
Published: February 2007

Hopfield model is a representative associative memory. It was improved to Bidirectional Associative Memory (BAM) by Kosko and to Multidirectional Associative Memory (MAM) by Hagiwara. They have two layers or multilayers. Since they have symmetric connections between layers, they ensure convergence. MAM can deal with multiples of many patterns, such as (x1,x2,…), wherexmis the pattern on layerm. Copyright © 2004 Wiley Periodicals, Inc.

Noest, Hirose, and Nemoto proposed complex‐value Hopfield model. Lee proposed complex‐valued Bidirectional Associative Memory. Zemel proved the rotation invariance of complex‐valued Hopfield model. It means that the rotated pattern in also stored.

In this paper, the complex‐valued Multidirectional Associative Memory is proposed. The rotation invariance is also proved. Moreover it is shown by computer simulation that the differences of angles of given patterns are automatically reduced.

At first we define complex‐valued Multidirectional Associative Memory. Then we define the energy function of network. With the energy function, we prove that the network ensures convergence.

Next, we define the learning law and show the characteristic of recall process. The characteristic means that the differences of angles of given patterns are automatically reduced. Especially we prove the following theorem. In the case that only a multiple of patterns is stored, if patterns with different angles are given to each layer, the differences are automatically reduced.

Finally, we investigate whether the differences of angles influence the noise robustness. It is found to reduce the noise robustness, because the input to each layer becomes small. We show this by computer simulations. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 39–45, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20387
Characteristics of PM synchronous motor drives with a trapezoidal EMF
Authors: Yonezawa Hiroyuki , Taniguchi Katsunori , Morizane Toshimitsu , Kimura Noriyuki
Published: February 2007

A permanent magnet synchronous motor (PMSM) with nonsinusoidal electromotive force (EMF) generates torque ripple even if the sinusoidal PWM inverter drives the PMSM. A new modified trapezoidal modulating signal for PWM inverter suitable for PMSM drive with nonsinusoidal EMF is proposed in this paper. A new modulating signal for the PMSM drive is determined by the condition of reducing torque ripple of the motor with various trapezoidal EMF. When the PWM inverter using modified trapezoidal modulating signal drives the PMSM having a nonsinusoidal EMF, the torque ripple of the motor can be reduced, the DC link voltage utilization is improved, and reduction of switching loss can be obtained. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 62–71, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20441
Synthesis and Reactions of Stannole Anions
Authors: Haga Ryuta , Saito Masaichi , Yoshioka Michikazu
Published: February 2007

The synthesis of stannole anions bearing various substituents on the tin atom is described. The reduction of hexaphenylstannole by the proper amount of lithium gave 1,2,3,4,5‐pentaphenylstannole anion 1. The reaction of 1 with 1,n‐dihaloalkanes (n = 1, 3, 4, 5, 6) gave the corresponding 1,n‐bis(1‐stannacyclopentadien‐1‐yl)alkanes. In contrast, the reaction of 1 with 1,2‐dihaloalkanes gave the 1,1′‐bistannole. The reactions of stannole dianion 3 with an equimolar amount of bulky alkyl, aryl, silyl, and stannyl halides gave the corresponding stannole anions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Molecular Ice with Hybrid Water–Bromide Network around a Cryptand with a Bromide Ion Included in the Cavity to Form a Host‐within‐a‐Host‐Like Structure
Authors: Das Madhab C. , Bharadwaj Parimal K.
Published: February 2007

A new mode of association of water molecules is described. Adamantanoid water clusters bonded to bromide ions as well as other water molecules form a cage within which bromide‐encapsulated aza cryptands reside to form a host‐within‐a‐host‐like structure. The structure of this adamantanoid water decamer is remarkably similar to that of cubic ice (Ic). The average O···O distance is 2.78 Å, which is close to 2.75 Å present in Ic, and the average O···O···O angle of 109.40° is also close to the tetrahedral angle in ice Ic.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Enantioselective Fluorescent Sensors for Chiral Carboxylates Based on Calix[4]arenes Bearing an L‐Tryptophan Unit
Authors: Qing Guang‐yan , He Yong‐bing , Wang Feng , Qin Hai‐juan , Hu Chen‐guang , Yang Xi
Published: February 2007

Two‐armed chiral calix[4]arenes (3a–c) functionalized at the lower ring with L‐tryptophan units have been prepared and the structures of these receptors characterized by IR, MS, 1H, and 13C NMR spectroscopy and elemental analysis. The enantioselective recognition of these receptors has been studied by fluorescence titration and 1H NMR spectroscopy. The receptors exhibited different chiral recognition abilities towards some enantiomers of chiral materials and formed 1:1 complexes between host and guest. Receptor 3a exhibits excellent enantioselective fluorescent recognition ability towards the N‐Boc‐protected alanine anion and 3b reveals good enantioselective recognition ability towards the enantiomers of mandelate.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Crystalline‐State Conformational Analysis of MαNP Esters, Powerful Resolution and Chiral 1H NMR Anisotropy Tools
Authors: Kuwahara Shunsuke , Naito Junpei , Yamamoto Yoko , Kasai Yusuke , Fujita Takuma , Noro Kazutoshi , Shimanuki Kumiko , Akagi Megumi , Watanabe Miwa , Matsumoto Takatoshi , Watanabe Masataka , Ichikawa Akio , Harada Nobuyuki
Published: February 2007

To compare the crystalline‐state conformations of MαNP acid esters with those existing in the solution state, X‐ray crystallographic analyses of 22 MαNP esters and two MαNP acids were carried out. It was found that all 27 conformers observed in the solid state have structures in which the 2‐CH3 group and the 2′‐H of the naphthyl group are synperiplanar and are almost always located in the same plane. In addition, the CH3–O7–C2–C1 moiety in all cases has an antiperiplanar structure within the MαNP plane. From further analyses, 22 conformers adopt the so‐called syn structure, in which the O7–C2–C1–O6 moiety is synperiplanar. On the other hand, the remaining five conformers have the so‐called anti structure. With regard to the rotational conformation around C1″–O5, all conformers have structures similar to the synperiplanar conformation. In the so‐called syn conformers, the interatomic distance d(H8′–O6) is distributed between 2.48 Å and 2.96 Å, while the distance d(H8′–O7) varies between 2.26 Å and 2.56 Å, indicating the weak bifurcated hydrogen bond between O6–H8′–O7 as the intramolecular stabilizing force. The crystalline‐state conformations of MαNP esters are thus similar to those in solution as determined by 1H NMR spectroscopy, implying that the intramolecular forces make a dominant contribution to the conformations of MαNP esters. The X‐ray crystallographic analyses of MαNP acids indicated that the O6–H(acid)–O7 bifurcated hydrogen bond also serves as an intermolecular force to stabilize the so‐called syn conformation. A similar bifurcated hydrogen bond [O6–H(alcohol)–O7] was observed in a MαNP ester containing a tertiary alcohol group. It should be emphasized that despite the existence of the so‐called syn and anti conformations in the crystalline state, the absolute configurations of all MαNP esters determined here by X‐ray crystallography all agree with those obtained by the 1H NMR anisotropy method.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Bending without breaking: examining the role of attitudinal ambivalence in resisting persuasive communication
Authors: Cavazza Nicoletta , Butera Fabrizio
Published: February 2007

The present research aims at showing that ambivalence may serve an adaptive function: to preserve attitudes and to resist persuasion. In two experiments, participants were exposed to a counter‐attitudinal message attributed to an ingroup majority. Results of both experiments showed that individuals high in ambivalence changed toward the source more than individuals low in ambivalence at the direct level, while at the indirect level––where the link between attitudes and the source's message is less apparent––individuals low in ambivalence changed toward the source more than individuals high in ambivalence. Experiment 2 also showed that this effect is particularly true for high self‐monitoring participants, thereby supporting a motivational interpretation of the effect. Copyright © 2007 John Wiley & Sons, Ltd.
Cytogenetic investigation on leukocytes of workers exposed to metallic mercury
Authors: Verschaeve L. , Tassignon J.‐P. , Lefevre M. , De Stoop P. , Susanne C.
Published: February 2007

A cytogenetic analysis was performed in 28 mercury‐exposed subjects as well as eight control subjects from the same chloralkali plant and in 12 healthy controls from the “general population.” No chromosomal effects could be demonstrated in the mercury‐exposed population in comparison with both control groups. Also no effect of smoking was observed. From the study it seems obvious that mercury, although it is capable of producing chromosomal damage even at low exposure levels, will not be harmful in this respect when adequate protection measures are taken.
Substrate‐specificity of uvr excision repair
Authors: Murray Michael L.
Published: February 2007

The substrate specificity of the uvr endonuclease, the product of the uvrA, urvB, and uvrC genes is reviewed. It is suggested that the relatively well‐defined substrate specificity of this repair enzyme is useful as a guide in determining the nature of the DNA‐lesion caused by a given mutagen.
Effects of epoxide hydratase inhibitors in forward and reversion bacterial mutagenesis assay systems
Authors: Guest Derek , Dent John G.
Published: February 2007

Cyclohexene oxide (CCHO) and 1,1,1‐trichloropropene‐2,3‐oxide (TCPO) are inhibitors of epoxide hydratase and have been used in studies of the mechanisms of mutagenesis in bacterial mutagenesis assays. The present studies were designed to investigate the mutagenic activity of CCHO and TCPO in Salmonella typhimurium employing the Ames histidine‐reversion assays (TA98, TA100, TA1535, TA1537, TA1538) and a forward mutation assay that uses 8‐azaguanine resistance in TM677 as the genetic marker. In the reverse mutation assay, TCPO (10−3 M) produced a mutagenic response in strains TA100 and TA1535 in the absence or presence of a rat liver metabolizing system (S9), indicating that TCPO causes base‐pair substitution mutations. CCHO (10−3 M) showed a slight but significant mutagenic effect in strain TA100, with or without S9 and, in strain TA1535, only in the absence of S9. In the forward assay, TCPO was a strong mutagen at concentrations above 5 × 10−5 M and was toxic to the bacteria. The mutagenic and toxic effects of TCPO were slightly reduced in the presence of the S9 preparation, suggesting that the epoxide may be metabolized by the microsomal enzymes. In the forward assay, CCHO showed no mutagenic activity but some toxicity at 3 × 10−3 M. When epoxide hydratase activity was measured under the conditions of the forward mutation assay, 85% inhibition of activity was observed at 10−3 M TCPO, a concentration that caused a 45‐fold increase in the mutation frequency. CCHO (3 × 10−3 M) produced a 55% inhibition of epoxide hydratase activity without exhibiting mutagenic effects in TM677. These results indicate that CCHO should be employed in preference to TCPO when inhibition of epoxide hydratase activity is required in bacterial mutagenesis studies.
Sex‐related differences in cytogenetic effects of benzene in the bone marrow of swiss mice
Authors: Meyne Julianne , Legator M. S.
Published: February 2007

Two routes of administration ‐ intraperitoneal injection and oral gavage ‐ and two methods of analysis ‐ direct metaphase preparations and the micronucleus test ‐ were used to investigate the cytogenetic effects of benzene exposure in the bone marrow of female and male Swiss (CD‐1) mice. The males demonstrated higher mean frequencies of metaphase aberrations and micronuclei after both routes of administration. The frequencies of metaphase aberrations appeared to be sex‐related and independent of the route of exposure, however, while the frequencies of micronuclei appeared to be dependent upon both the sex of the animals and the route of administration.
Mutagenicity of 2‐ and 3‐carbon halogenated compounds in the salmonella/mammalian‐microsome test
Authors: Stolzenberg S. J. , Hine C. H.
Published: February 2007

Short‐chain, 2‐ and 3‐carbon halogenated hydrocarbons were tested for mutagenicity for Salmonella typhimurium strain TA 100 both with and without the presence of S‐9. Without exception, all brominated derivatives were more mutagenic than the chlorinated derivatives, usually by a substantial order of magnitude. 2‐Fluoroethanol, the only fluorinated compound tested, showed little or no mutagenic activity up to 100 μmole per plate concentration. Two highly purified propane derivatives containing a halogen atom on each of the three carbons showed little or no direct mutagenic activity. A third trihalogenated compound with a halogen atom on each carbon atom showed some direct mutagenic activity, probably due to impurities. However, all three trihalogenated compounds were highly active mutagens following S‐9 activation. The presence of a double bond in the case of 1,2,3‐trichloropropene resulted in a higher level of direct mutagenic activity than 1,2,3‐trichloropropane, but activation with S‐9 resulted in a further increase in mutagenic activity with the former compound. On the other hand, S‐9 caused a substantial decrease in mutagenic activity of most compounds containing a double bond. With the presence of an alcoholic group in a compound, the addition of S‐9 caused variable responses, increasing the number of his+ revertant colonies due to 2,3‐dibromopropanol but had little or no effect with five other compounds containing an alcoholic group. Evidence is also presented that the position of a double bond in relation to the halogen atoms may influence mutagenic activity.
Ii. Comparative extraction of houston air particulates with cyclohexane or a mixture of benzene, methanol, and dichloromethane
Authors: Preidecker Barbara Lee Borns
Published: February 2007

A recent study (see preceding article) was conducted to evaluate bacterial mutagenicity of extracted particulates collected from air in Houston, Texas. Initially the solvent system used to extract these particulates was the 1:1:1 v/v mixture of benzene, methanol, and dichloromethane used by Pitts et al [1] in a similar study in California. Because of recent concern about the genetic toxicity of benzene, efforts are being made, where possible, to substitute other solvents, and a suggestion was made to try cyclohexane.

The recent National Institute for Occupational Safety and Health (NIOSH) documents on exposure to coal tar [2] and to asphalt fumes [3] have recommended use of cyclohexane to extract air samples from occupationally exposed air filters. In addition, recent publications [4–6] have used cyclohexane to extract polyaromatic hydrocarbons (PAH) and aliphatic hydrocarbons from particulate air samples. A study done by Stanley et al [7] found cyclohexane almost 100% efficient at extracting benzo(a)pyrene. The present study was designed to examine the difference in efficiency of extraction between cyclohexane and a 1:1:1 mixture of benzene, methanol, and dichloromethane, using the Ames assay as a test for mutagenicity.
X irradiation and sister chromatid exchange in cultured human lymphocytes
Authors: Morgan William F. , Crossen Peter E.
Published: February 2007

Sister chromatid exchange (SCE) frequency was not increased in G0 lymphocytes following irradiation up to 400 rads. Lymphocytes irradiated after 42 or 60 hours of culture showed a dose‐dependent increase in exchange frequency at 100 and 200 rads. SCE was not increased in cells irradiated in G2 (68.5 hours).

Lymphocytes maintained in a 5‐Bromodeoxyuridine (BrdUrd) free medium and irradiated 42 hours after culture initiation showed an increase in SCE if BrdUrd was added immediately after irradiation, but no increase was found if there was a 5 hour holding period prior to the addition of BrdUrd.

The effect on induced SCE frequency of heightened radiosensitivity due to increased amounts of BrdUrd was also investigated. When the BrdUrd concentration was increased from 10 μg/ml to 50 μg/ml, the percent increase in X‐ray‐induced SCE was lower at 50 μg/ml. In addition, increased BrdUrd concentration only slightly increased the sensitivity of the SCE technique to irradiation doses of 50 rads.
Sunlight‐induced mutagenesis and toxicity in L5178Y mouse cells: Determination and comparison with other light sources
Authors: Krell Kenneth , Jacobson Elizabeth D.
Published: February 2007

Compared on the basis of equal exposure, in joules per square meter (J/m2) the mutagenic and toxic effects in L5178Y mouse lymphoma cells of radiation emitted by some fluorescent lamps and a sunlamp are quantitatively similar to solar radiation effects at the earth's surface. When the relative intensities of radiation are taken into account, the artificial light sources range from 8 to 1 /222 times as mutagenic and 4.1 to < 1 /99 times as toxic as sunlight.
Clastogen‐induced micronuclei in peripheral blood erythrocytes: The basis of an improved micronucleus test
Authors: MacGregor James T. , Wehr Carol M. , Gould Daniel H.
Published: February 2007

Micronuclei induced in bone marrow erythroblasts by clastogenic chemicals are easily detected in peripheral blood. In mice treated with nitrogen mustard, 7,12 dimethylbenz(a)anthracene, or cyclophosphamide, the peak incidence of micronucleated polychromatic erythrocytes in peripheral blood was at least as great as the maximum incidence in bone marrow. In each case the peak incidence in blood occurred on the day following the peak incidence observed in bone marrow. Thus, for general genetic screening purposes, monitoring micronuclei in peripheral blood rather than in bone marrow smears provides at least equal sensitivity, offers greater simplicity in sample preparation and scoring, permits multiple sampling of treated animals, and may also facilitate automated scoring and human cytogenetic monitoring.
The evaluation of the epoxide diluent, n‐butylglycidyl ether, in a series of mutagenicity assays
Authors: Connor T. H. , Ward J. B. , Meyne J. , Pullin T. G. , Legator M. S.
Published: February 2007

The epoxide diluent, n‐butylglycidyl ether (n‐BGE), was tested in vitro for mutagenicity using Salmonella typhimurium and for transforming ability in mouse embryo cells (Balb/3T3‐A31‐1‐13). The n‐BGE produced base‐pair type mutations in S typhimurium strains TA1535 and TA100. However, it failed to transform mouse embryo cells when assayed up to toxic levels. The mutagenic activity could not be detected in the urine of mice, although several doses, routes of administrations, and lengths of exposure were examined. Orally adminsitered n‐BGE did not produce any increase in micronuclei in mice, but when the diluent was administered intraperitoneally, either one or two times, dose‐related increases in the number of micronuclei were observed.
Chemically‐induced unscheduled DNA synthesis in primary rat hepatocyte cultures: A comparison with bacterial mutagenicity using 218 compounds
Authors: Probst Gregory S. , McMahon Robert E. , Hill L. E. , Thompson Christina Z. , Epp J. K. , Neal S. B.
Published: February 2007

The autoradiographic identification of unscheduled DNA synthesis (UDS) in primary cultures of adult rat hepatocytes (HPC) has been proposed as a predictive test for mutagens/carcinogens. To assess the predictive value of this test, results in the hepatocyte UDS assay were compared with data for bacterial mutagenicity using a modified Ames test. Over 200 compounds representing a variety of chemical classes consisting of procarcinogens, ultimate carcinogens, and noncarcinogens were tested in each system. The accurate discrimination of many carcinogens/noncarcinogens was demonstrated by both systems. The induction of UDS in hepatocytes showed an excellent correlation with bacterial mutagenesis in response to polycyclic aromatic hydrocarbons, aromatic amines, biphenyls, nitrosamines, carbamates, azo‐compounds, acridines, halogenated compounds, nitrosureas, quinolines, pyridines, purines, pyrimidines, esters and carbamates. Nitrocompounds, although active in bacteria, were poor inducers of UDS. The results support the complementary and confirmatory nature of these tests for genotoxic chemicals and indicate the usefulness of the hepatocyte UDS system as a component in a battery of short‐term predictive tests for mutagens/carcinogens.
Induction of sister chromatid exchanges in human diploid fibroblasts by mutagens with and without rat liver microsomal activation
Authors: Yang D. P. , Graupensperger F. , Minecci L. C. , Rubin B. A.
Published: February 2007

The frequency of sister chromatid exchange (SCE) in WI‐38 cells was estimated by the 5‐bromodeoxyuridine (BrdUrd)‐dye technique after one hour's exposure to cyclophosphamide (CY), N‐methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG), 4‐nitroquinoline‐1‐oxide (4NQO), and maleic hydrazide (MH) with and without the addition of rat liver microsomal suspension (S‐9) fraction with co‐factors (S‐9 mix). CY at concentrations from 1 × 10−5M to 1 × 10−3M with S‐9 mix increased the number of SCEs per cell in a dose‐dependent manner. Without S‐9 mix, CY at concentrations below 1 × 10−3M failed to produce more SCEs than the controls. MNNG at 1 × 10−8M and 4NQO at 1 × 10−7M without S‐9 produced significant increases in SCEs per cell. Addition of S‐9 during treatment slightly decreased the effects of MNNG and 4NQO in the formation of SCEs. MH was tested at pH 6.4 and pH 7.6. At pH 7.6, MH at 1 × 10−3M without S‐9 mix inhibited cell multiplication, but did not cause a significant increase of SCEs per cell. There were no interactions between MH (2 × 10−4M) and S‐9 mix nor between MH and the pH levels tested. These results indicate that in the presence of metabolic activation, SCE formation in human diploid fibroblasts in vitro may be used as a potential assay for mutagenicity.
Perspectives in mutagenesis
Authors: Malling Heinrich V.
Published: February 2007

I would first like to thank the Environmental Mutagen Society for honoring me with its 1980 award; I also would like to take this opportunity to acknowledge all the people who have worked with me and helped me since I started my work in mutagenesis in 1953. I feel especially indebted to my wife, Martha, whose support has been absolutely essential for my career.

I would now like to explore some important problems in environmental mutagenesis. Obviously, I cannot touch upon new developments in all aspects of environmental mutagenesis ‐ a field that has become increasingly broad in recent years. As in the past, there continue to be major advances in understanding mechanisms of mutagenesis, developing short‐term tests, characterizing mutations, elucidating the relationship between mutagenesis and carcinogenesis, understanding the metabolism of mutagens, and many other areas. Many of these advances are reflected in the contents of the papers, symposia, and poster sessions of this meeting. In the years that I have been involved in mutation research and environmental mutagenesis, my interests and research activity have spanned a number of these areas; and I am pleased by the recent progress that I see taking place in them. In this talk, however, I would like to direct my comments toward a rather new dimension in environmental mutagenesis in which I have become increasingly interested: The monitoring of mutations in the human population.

In the monitoring of the human population there are two choices: We can monitor the progeny of an exposed population or we can consider exposed persons as populations of cells and measure the mutant frequency in individual cells in these persons. Technical developments are advancing rapidly in both of these approaches. The pioneering work of James Neel in measuring germinal effects of mutagens in the human population is well known [Neel, 1970]. Methods for measuring mutation frequencies in single cells in vivo also are beginning to be available. For instance, Strauss and Albertini [1979] are developing a system to detect HGPRT mutants in human lymphocytes. Of course, there are still difficult problems to be resolved in this system; and we do not know with certainty.
Evaluation of the release of mutagens from diesel particles in the presence of physiological fluids
Authors: King Leon C. , Kohan Mike J. , Austin Ann C. , Claxton Larry D. , Huisingh J. Lewtas
Published: February 2007

The Ames Salmonella typhimurium plate incorporation assay was used to evaluate the mutagenicity of organics extracted from diesel exhaust particles. Organic solvents were more efficient than physiological fluids in removing mutagens from diesel particles, with dichloromethane extracts having the greatest mutagenic activity of the solvents examined. Serum and lung cytosol were more effective than acellular lung lavage fluid in releasing mutagenic activity from diesel particles. The mutagenic activity of diesel particle organics preextracted with dichloromethane is greatly reduced upon the addition of serum and lung cytosol to organics. Subsequently, incubation of protease with serum and lung cytosol‐bound diesel organics increases the mutagenic activity. Fluorescence intensity was quantitated and found to correlate with mutagenic activity in the organic and serum extracts, but not the lung cytosol extracts. These studies suggest that substantial mutagenic activity is released from diesel particles upon incubation with serum and lung cytosol.
Cytotoxic and mutagenic properties of shale oil byproducts I. Activation of retort process waters with near ultraviolet light
Authors: Strniste Gary F. , Chen David J.
Published: February 2007

Cultured Chinese hamster ovary (CHO) cells were exposed to dilutions of shale oil retort process waters obtained from three different retorting processes located in the Green River oil shale formations in the western part of the United States. Although the intensity of the response was dictated by the process water used, all induced a cytotoxic (reduction in colony‐forming ability) and mutagenic (induced at the hypoxanthine‐guanine phosphoribosyl transferase (HGPRT) locus) response in cells pretreated with dilutions of the waters and subsequent exposure to near ultraviolet light (NUV). Combinations of process water plus NUV yielded mutation frequencies as great as 50% that witnessed for the mutation frequency induced by the potent carcinogen far ultraviolet light. NUV alone was nontoxic and nonmutagenic at the doses of radiation used. Exposure of CHO cells in the dark to nontoxic dilutions of the process waters resulted in small but significant increases in 6‐thioguanine resistant mutants (1–2 times background rates). The biological consequences resulting from the disposal of retort process waters into the delicate environment present in this oil shale region could be further complicated by this photoactivating process.
Cytotoxicity and mutagenicity of the fungicides captan and folpet in cultured mammalian cells (CHO/HGPRT system)
Authors: O'neill J. Patrick , Forbes Nancy L. , Hsie Abraham W.
Published: February 2007

The cytotoxicity and mutagenicity of the fungicides captan and folpet were determined in the CHO/HGPRT system which utilizes Chinese hamster ovary cells and resistance to 6‐thioguanine to estimate mutation induction at the hypoxanthine‐guanine phosphoribosyl transferase locus. Treatment of cultures with each compound for 5 hr in serum‐free medium resulted in reproducible, significant, concentration‐dependent increases in the frequency of 6‐thioguanine‐resistant mutants.
Anaphase aberrations: A measure of genotoxicity in mutagen‐treated fish cells
Authors: Kocan R. M. , Landolt M. L. , Sabo K. M.
Published: February 2007

Rainbow trout gonad cells (RTG‐2) were cultured for various lengths of time in the presence of several classes of known mutagenic chemicals and several related compounds that possessed no known mutagenic/carcinogenic activity. During the course of exposure the cells were examined for the presence of abnormalities in the chromosome arrangement of anaphase figures during mitosis. Untreated and solvent‐treated (dimethylsulfoxide‐treated) cells exhibited a background abnormality rate of 12% with only minor chromosomal defects being observed. This was also true for those cells exposed to naphthol and anthracene, two chemicals with no proven mutagenic or carcinogenic activity. Conversely, significant increases in the frequency of anaphase aberrations were produced in cells treated with N‐methyl‐N′‐nitro‐N‐nitrosoguanidine, benzo(a)pyrene, 9‐aminoacridine and mitomycin‐C. These abnormalities were also far more complex and extensive than those observed in the control and nonmutagen‐treated cells. Many species of fish have extremely small and numerous chromosomes, making resolution of chromosome defects such as sister chromatid exchange and deletions more difficult than in most mammalian diploid cells, which generally have larger and fewer chromosomes. Examination of cells during anaphase eliminates the need to observe each chromosome separately as well as the need to produce well‐spread metaphase chromosomes. Since the sensitivity of anaphase aberrations to known mutagenic/carcinogenic compounds appears to be quite high in trout cells and since hundreds of suitable cells are available for analysis, this may be an appropriate alternative or addition to some of the more standard chromsosome macrolesion tests developed in mammalian systems.
Effect of diesel exhaust emissions, particulates, and extract on sister chromatid exchange in transplacentally exposed fetal hamster liver
Authors: Pereira Michael A. , McMillan Lofton , Kaur P. , Gulati D. K. , Sabharwal P. S.
Published: February 2007

The genotoxic activity of diesel exhaust emissions, particulate matter, and an organic extract of the particulate matter was evaluated in transplacentally exposed Syrian hamster fetal liver cells. The frequency of sister chromatid exchange (SCE) was determined on day 13 of gestation. The extract of diesel particulate matter caused a dose‐dependent increase in the frequency of SCE with a doubling in the incidence above 320mg/kg. The diesel particulate matter and diesel exhaust emissions did not alter the frequency of SCE. The extract and particulate matter did cause a dose‐dependent decrease in the mitotic activity of the fetal liver. The in utero SCE analysis was demonstrated to be a sensitive assay for determination of the genotoxic activity of a complex mixture in transplacentally exposed fetuses.
Comparison of microsomal inducer pretreatment on the in vitro α‐hydroxylation and mutagenicity of N‐nitrosopyrrolidine in rat and hamster liver
Authors: McCoy G. David , Hecht Stephen S. , McCoy Elena C.
Published: February 2007

The effect of modifiers of liver mixed function oxidase activity on the in vitro α‐hydroxylation and mutagenicity of N‐nitrosopyrrolidine (NPYR) has been examined in rats and hamsters. Hamster post‐mitochondrial supernatants were able to convert NPYR to a mutagen more efficiently than rat preparations under all conditions studied. Aroclor 1254 pretreatment caused the greatest increase in mutagenic activity in both species while phenobarbital and 3‐methylcholanthrene pretreatment gave intermediate values when compared to uninduced preparations. Microsomal α‐hydroxylation of NPYR was induced by Aroclor 1254 pretreatment in both species. Pretreatment with 3‐methylcholanthrene increased α‐hydroxylation in hamsters but decreased it in rats. Phenobarbital pretreatment only slightly increased microsomal α‐hydroxylation in either species. When microsomal α‐hydroxylation rates were expressed per gram wet weight of liver, better agreement between rates of α‐hydroxylation and mutagenicity in phenobarbital pretreated animals was obtained since inducer associated changes in total microsomal protein content were taken into account. An example of differential induction of an activation pathway (α‐hydroxylation) and a degradative pathway (aldehyde dehydrogenase) is presented to illustrate a potential source of error in the interpretation of metabolic data obtained from post‐microsomal supernatants and whole animal studies.
Sister chromatid exchange induced by short‐lived monoadducts produced by the bifunctional agents mitomycin C and 8‐methoxypsoralen
Authors: Linnainmaa Kaija , Wolff Sheldon
Published: February 2007

To see if DNA crosslinks are involved in the induction of sister chromatid exchange (SCE), Chinese hamster ovary cells were exposed to two bifunctional alkylating agents, mitomycin C and 8‐methoxypsoralen, and their monofunctional derivatives, decarbamoyl mitomycin C and angelicin. The data indicate that monoadducts, rather than crosslinks, are responsible for SCE formation. Furthermore, all agents but angelicin produced short‐lived lesions that led to SCEs in the first period of DNA replication after treatment (twin SCEs), but not in the second (single SCEs). In contrast, angelicin, like methyl methanesulfonate and N‐acetoxyacetylaminofluorene, produced lesions that lasted more than one cycle, indicating that several different types of DNA lesions are capable of SCE induction.
Neuroblast of the grasshopper embryo as a new mutagen test system. Ii. Chromosome breakage induced by in vitro exposure of embryos to the direct‐acting mutagens 4NQO, MNNG, adriamycin, and bleomycin
Authors: Liang Jan C. , Gaulden Mary Esther
Published: February 2007

The dose‐response for the induction of acentric chromosome fragments was determined in neuroblasts of the grasshopper embryo (Chortophaga viridifasciata De Geer, Orthoptera: Acrididae) exposed in vitro to four direct‐acting chemicals known to be mutagenic, clastogenic, and carcinogenic: 4‐nitroquinoline‐1‐oxide (4NQO), N‐methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG), Adriamycin (ADM), and bleomycin (BLM). After a 1‐hr exposure followed by a 3‐hr recovery period (untreated cell cycle time is 4 hr), acentric fragments were observed at doses down to 1 μM 4NQO, 1.25 μM M MNNG, and 0.125 μM ADM and BLM. After an 8‐hr continuous exposure, acentric fragments were induced by 4NQO at a dose as low as 0.125 μM. These low concentrations also reduced the number of dividing cells. No chromosome aberrations or mitotic effects were observed in untreated embryos or in those exposed only to the solvent dimethyl sulfoxide.

Because of the short cell cycle and the sensitivity of the neuroblast to the induction of acentric chromosome fragments by chemical clastogens, a minimum of time is needed to perform the test. From a comparison with the prominent clastogen test systems currently used, it is concluded that the grasshopper neuroblast test is the fastest and that it detects some agents that some systems do not. Grasshoppers have a worldwide distribution. If neuroblasts of other species prove to be as sensitive to mutagens as those of Chortophaga, investigators in many countries would have available a eukaryotic mutagen test system that is simple, fast, reproducible, and inexpensive.
Phenotypic expression time of mutagen‐induced 6‐thioguanine resistance in Chinese hamster ovary cells (CHO/HGPRT system): Expression in division‐arrested cell cultures
Authors: O'Neill J. Patrick , Machanoff Richard , Hsie Abraham W.
Published: February 2007

The phenotypic expression time of ethyl methanesulfonate (EMS) induced 6‐thioguanine‐resistant mutants was studied with Chinese hamster ovary cells in culture (CHO/HGPRT system). After mutagen treatment of exponential phase cultures, the cells were maintained either in the exponential phase through subculture in medium containing 5% dialyzed fetal bovine serum (FBS) or in a nondividing viable state by use of medium containing 0–1 % dialyzed FBS. The time course of expression of the 6‐thioguanine‐resistant phenotype was similar with both exponential phase and division‐arrested cultures showing maximum expression by 9 days after mutagen treatment, and both methods of expression also yielded similar mutant frequencies over a range of EMS concentrations. This study shows that once the mutagenic event is fixed, the expression of the mutant phenotype does not require continued cell division since it occurs in division‐arrested cultures. These results also suggest that both dilution of pre‐existing hypoxanthine‐guanine phosphoribosyl transferase (HGPRT) enzyme by cell division and turnover by protein degradation are involved in the phenotypic expression. Both processes occur in exponential cultures, but only protein turnover in arrested cultures. Consistent with this was the demonstration that the rates of total cell protein turnover increased in division‐arrested cultures maintained in serum‐free medium. These results separate genetic damage and phenotypic expression in a temporal sense, and point out the need to consider the mechanisms responsible for each process involved in the induction and expression of mutations.
Studies of cytogenetic effects of sodium arsenicals on mammalian cells in vitro
Authors: Wan Bojian , Christian Robert T. , Soukup S. W.
Published: February 2007

The cytotoxic and cytogenetic effect of sodium arsenite and sodium arsenate on Chinese hamster ovary (CHO) cells is reported. Chromosome aberrations were induced with both arsenic compounds. Trivalent arsenic was more clastogenic than pentavalent arsenic. Sodium arsenite was also shown to produce increased sister chromatid exchange in CHO cells and increased chromosome breakage in human lymphocytes.