bluuebunny/crossref_metadata_2025 huggingface dataset:
Generalized Poincaré-Hopf Theorem for Compact Nonsmooth Regions
Authors: Simsek Alp , Ozdaglar Asuman , Acemoglu Daron
Published: February 2007

This paper presents an extension of the Poincaré-Hopf theorem to generalized critical points of a function on a compact region with nonsmooth boundary, M, defined by a finite number of smooth inequality constraints. Given a function F: M ↦ ℝn, we define the generalized critical points of F over M, define the index for the critical point, and show that the sum of the indices of the critical points is equal to the Euler characteristic of M. We use the generalized Poincaré-Hopf theorem to present sufficient (local) conditions for the uniqueness of solutions to finite-dimensional variational inequalities and the uniqueness of stationary points in nonconvex optimization problems.
Development of a resource protection and waste strategy for water use by the agricultural sector
Authors: Ligthelm M.E. , Ranwedzi R. , Morokane M. , Senne M.
Published: February 2007

The South African Department of Water Affairs and Forestry (DWAF) has started developing a strategy to regulate activities and water uses by the agricultural sector that could impact on the water resource quality. The aim would not be to over-regulate the sector, but to protect the water resource where necessary. Most of these activities constitute diffuse sources of potential pollution. The strategic process will start with investigative discussions with major stakeholders and determining the strategic context and current situation. The latter will consist of a detailed literature and stakeholder survey, and an evaluation of existing agricultural activities. The next steps of determining a vision and the setting of strategic objectives will be done with active participation by the major players. An action plan will be developed to achieve the set objectives.

Important components of the strategy will be to: classify activities according to their risk to the water resource, taking into account the sensitivity of the water resource; set regulatory measures in accordance with the risk posed by the activity (measures could include the promulgation of regulations, general authorisations and/or issuing of licenses); harmonise and link the process with existing relevant processes and guidelines within DWAF and other government departments; review existing guidelines; sign agreements with relevant government departments and the agricultural sector; and provide training, built capacity and raise awareness during and after the process.
Determination of first flush criteria using dynamic EMCs (event mean concentrations) on highway stormwater runoff
Authors: Kim L.-H. , Jeong S.-M. , Ko S.-O.
Published: February 2007

Recently the Ministry of Environment in Korea has developed the total maximum daily load program in accordance with the target pollutant and its concentration goal on four major large rivers. Since the program is largely related to regional development, nonpoint source control is both important and topical. Of the various nonpoint sources, highways are stormwater intensive land uses since they are impervious and have high pollutant mass emissions from vehicular activity. The event mean concentration (EMC) is useful in estimating the loadings to receiving water bodies. However, the EMC does not provide information on the time varying changes in pollutant concentration or mass emissions, which are often important for best management practice development, or understanding shock loads. Therefore, in this study a new concept, the dynamic EMC determination method, will be introduced to clearly verify the relationship between EMC and the first flush effect. Three monitoring sites in Daejeon metropolitan city areas were equipped with an automatic rainfall gauge and a flow meter for accumulating the data such as rainfall and runoff flow. The dynamic EMC method was applied to more than 17 events, and the improved first flush criteria were determined on the ranges of storm duration and accumulated rainfall.
Phase Segregation in Thin Films of Conjugated Polyrotaxane– Poly(ethylene oxide) Blends: A Scanning Force Microscopy Study
Authors: Sardone L. , Williams C. C. , Anderson H. L. , Marletta G. , Cacialli F. , Samorì P.
Published: February 2007

Scanning force microscopy (SFM) is used to study the surface morphology of spin‐coated thin films of the ion‐transport polymer poly(ethylene oxide) (PEO) blended with either cyclodextrin (CD)‐threaded conjugated polyrotaxanes based on poly(4,4′‐diphenylene‐vinylene) (PDV), β‐CD–PDV, or their uninsulated PDV analogues. Both the polyrotaxanes and their blends with PEO are of interest as active materials in light‐emitting devices. The SFM analysis of the blended films supported on mica and on indium tin oxide (ITO) reveals in both cases a morphology that reflects the substrate topography on the (sub‐)micrometer scale and is characterized by an absence of the surface structure that is usually associated with phase segregation. This observation confirms a good miscibility of the two hydrophilic components, when deposited by using spin‐coating, as suggested by the luminescence data on devices and thin films. Clear evidence of phase segregation is instead found when blending PEO with a new organic‐soluble conjugated polymer such as a silylated poly(fluorene)‐alt‐poly(para‐phenylene) based polyrotaxane (THS–β‐CD–PF–PPP). The results obtained are relevant to the understanding of the factors influencing the interfacial and the intermolecular interactions with a view to optimizing the performance of light‐emitting diodes, and light‐emitting electrochemical cells based on supramolecularly engineered organic polymers.
Copper/Polyimide Heterojunctions: Controlling Interfacial Structures Through an Additive‐Based, All‐Wet Chemical Process Using Ion‐Doped Precursors
Authors: Ikeda S. , Yanagimoto H. , Akamatsu K. , Nawafune H.
Published: February 2007

Heterojunctions comprising copper thin films and polyimide underlayers are exploited as an important system for generating flexible microelectronic circuit elements. A fully additive‐based chemical method that allows metallization of polyimide films with copper by the in situ reduction of copper ions doped in surface‐modified polyimide precursors is reported. It is shown that dimethylamine borane is a good reducing agent for copper ions initially complexed with carboxylate anions in the hydrolyzed polyimide layers. This reduction allows diffusion of copper ions towards the film surface to form copper thin films, and simultaneously controls the fabrication of interfacial microstructures between the copper and underlying polyimide. The formation of copper thin films and composite layers is elucidated by glow‐discharge optical emission spectrometry depth profiling, scanning electron microscopy, and cross‐sectional transmission electron microscopy studies, and it is shown that the final microstructure at the copper/polyimide interface is dependent upon experimental variables: a larger amount of copper ions incorporated into the modified layers and a higher reduction rate result in the formation of a granular layer containing smaller copper nanoparticles near the film surface. The granular layers thus formed are found to play a critical role in achieving strong adhesion between metal thin films and the substrate, owing to the increased contact area and hence the increased work of adhesion between them. These results have important implications for realizing a novel adhesion scheme between deposited metals and underlying dielectrics based on nanoscale interlocking through metal nanoparticles.
Streaming potential characterization of LBL membranes on porous ceramic supports
Authors: Chen Yiwei , Xiangli Fenjuan , Jin Wanqin , Xu Nanping
Published: February 2007

An in‐situ characterization of the growth of the self‐assembled polyelectrolyte membranes on the porous support was conducted by applying transmembrane streaming potential measurement via surface charge monitoring. The membranes were prepared by layer‐by‐layer alternative deposition of poly (allylamine hydrochloride) and poly (styrenesulfonate) on porous ceramic supports. The surface charge variations of membranes as functions of different top‐assembled materials and numbers of deposited cycles were investigated. Different top‐assembled materials make isoelectric points of the as‐prepared membranes drift in opposite directions and also lead to symmetrical signal changes of zeta‐potential in salt solutions at the isoelectric points of the supports. Ex‐situ characterizations, including scanning electron microscopy, atomic force microscopy, and energy dispersive X‐ray spectroscopy, also confirm the alternative deposition of polyelectrolytes. It is demonstrated that the transmembrane streaming potential measurement is effective in studying the growth of layer‐by‐layer membranes on porous support. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Health-related quality of life after gastric banding
Authors: Mathus-Vliegen E M H , de Wit L T
Published: February 2007

Background

Bariatric surgery ameliorates obesity-associated diseases, resulting in psychological and social benefits. Long-term studies of its effects on quality of life (QOL) assessed with well established instruments are lacking. This prospective study investigated the long-term effects of gastric banding on health-related QOL using an obesity-specific validated measure.

Methods

The Health Related Quality of Life (HRQL) questionnaire was completed by 50 severely obese patients before surgery and at 1, 2·5 and 5 years after gastric banding. Ninety-eight subjects with normal weight, matched for age, sex and education, also completed the HRQL questionnaire as controls.

Results

Surgery was successful in all patients. Mean excess weight loss after 1, 2·5 and 5 years was 42·1, 42·2 and 41·6 per cent respectively. General wellbeing, health distress, depression, perceived attractiveness and self-worth improved significantly over the 5 years and, except for general wellbeing, were still improving after 5 years. There were increases in physical activity and work productivity. Successful weight loss was the main determinant of general wellbeing and health distress, and these were adversely affected by band-related complications. In subjects with a body mass index below 30 kg/m2, scores improved to values for subjects of normal weight.

Conclusion

Bariatric surgery resulted in sustained improvement in health-related QOL even though not all excess weight was lost. Normalization of health-related QOL may necessitate greater weight losses.
Secophnane‐Type Alkaloids from Daphniphyllum oldhami
Authors: Mu Shu‐Zhen , Yang Xian‐Wen , Di Ying‐Tong , He Hong‐Ping , Wang Ye , Wang Yue‐Hu , Li Ling , Hao Xiao‐Jiang
Published: February 2007

Four new alkaloids, daphnioldhanins D–G (1–4, resp.), together with five known alkaloids, daphmacropodine (5), secodaphniphylline (6), deoxycalyciphylline B (7), deoxyisocalyciphylline B (8), and daphmanidin A (9), were isolated from the roots of Daphniphyllum oldhami. Their structures were elucidated on the basis of spectroscopic data and chemical methods. Compound 1 at 2.0 μM showed potent antioxidant activity against H2O2‐induced impairment in PC12 cells.
Selective Synthesis and Reactivity of η5‐Arylcyclohexadienyliron Complexes
Authors: Owen David A. , Malkov Andrei V. , Palotai Ian M. , Roe Caroline , Sandoe Elizabeth J. , Stephenson G. Richard
Published: February 2007

A series of aryl‐substituted cyclohexadienyliron complexes have been prepared by a general procedure that determines regioselectivity by correctly positioning leaving groups in the precursor complexes. The aryl groups at 1‐C or 2‐C have been shown to be ω directing by the study of reactions with a representative range of nucleophiles, and these regioselectivity properties have been related to the spectroscopic properties of the cationic cyclohexadienyliron complexes. A high level of electron‐donating substituents on the arene, or switching between the [Fe(CO)3] and [Fe(CO)2PPh3] series, reduces the minor ipso pathway, improving regiocontrol. Placing opposed directing groups in the arylcyclohexadienyliron complexes reverts reactivity to the ipso pathway with stabilised enolate nucleophiles, and when the additional directing group reinforces the effect of the aryl group, the ipso pathway is stopped.
2,4,5‐Trinitroimidazole‐Based Energetic Salts
Authors: Gao Haixiang , Ye Chengfeng , Gupta Om D. , Xiao Ji‐Chang , Hiskey Michael A. , Twamley Brendan , Shreeve Jean'ne M.
Published: February 2007

2,4,5‐Trinitroimidazolate (TNI) salts with “high‐nitrogen” cations tend to be highly hydrogen bonded and have heats of formation ranging up to 616 kJ mol−1. Density, oxygen balance, and thermostability are enhanced by the presence of TNI. Based on theoretical calculations, all of the new salts are potential propellants.
Impact of a 21‐gene RT‐PCR assay on treatment decisions in early‐stage breast cancer
Authors: Lyman Gary H. , Cosler Leon E. , Kuderer Nicole M. , Hornberger John
Published: February 2007

BACKGROUND

The prognostic accuracy for distant recurrence‐free survival using a 21‐gene reverse‐transcriptase polymerase chain reaction (RT‐PCR) assay underwent validation in 668 lymph node‐negative, estrogen receptor‐positive women with early‐stage breast cancer receiving tamoxifen on National Surgical Adjuvant Breast Program (NSABP) B‐14. The predictive accuracy for treatment efficacy also underwent validation in 651 patients randomized on NSABP B‐20 and 645 patients on NSABP B‐14.

METHODS

Patients were classified as high (recurrence score [RS] ≥ 31), intermediate (RS 18–30), or low (RS < 18) risk for distant recurrence at 10 years. Cost‐effectiveness ratios were estimated for RS‐guided treatment compared with either tamoxifen alone or the combined chemotherapy and tamoxifen.

RESULTS

Distant recurrence was reported in RS low‐risk, intermediate‐risk, and high‐risk patients at 10 years in 3.7%, 17.8%, and 38.3% receiving tamoxifen alone and 5.0%, 10.1%, and 11.1% receiving the chemotherapy and tamoxifen. RS‐guided therapy is associated with a gain in individual life expectancy of 2.2 years compared with tamoxifen alone, whereas it is associated with similar life expectancy to that seen with the chemotherapy and tamoxifen strategy. RS‐guided therapy is estimated to provide a net cost savings of $2256 compared with chemotherapy and tamoxifen with an incremental cost‐effectiveness ratio of $1944 per life year saved compared with tamoxifen alone.

CONCLUSIONS

Treatment decisions based on RS‐guided therapy compared with tamoxifen alone are associated with greater efficacy with acceptable cost‐effectiveness ratios, and associated with similar efficacy and lower cost compared with chemotherapy and tamoxifen for patients with lymph node‐negative, estrogen receptor‐positive early‐stage breast cancer. Cancer 2007 © 2007 American Cancer Society.
Mutagenesis studies in transgenic Xenopus intermediate pituitary cells reveal structural elements necessary for correct prion protein biosynthesis
Authors: van Rosmalen Jos W.G. , Martens Gerard J.M.
Published: February 2007

The cellular prion protein (PrPC) is generally accepted to be involved in the development of prion diseases, but its physiological role is still under debate. To obtain more insight into PrPC functioning, we here used stable Xenopus transgenesis in combination with the proopiomelanocortin (POMC) gene promoter to express mutated forms of Xenopus PrPC fused to the C‐terminus of the green fluorescent protein (GFP) specifically in the neuroendocrine Xenopus intermediate pituitary melanotrope cells. Similar to GFP‐PrPC, the newly synthesized GFP‐PrPCK81A mutant protein was stepwise mono‐ and di‐N‐glycosylated to 48‐ and 51‐kDa forms, respectively, and eventually complex glycosylated to yield a 55‐kDa mature form. Unlike GFP‐PrPC, the mature GFP‐PrPCK81A mutant protein was not cleaved, demonstrating the endoproteolytic processing of Xenopus PrPC at lysine residue 81. Surprisingly, removal of the glycosylphosphatidylinositol (GPI) anchor signal sequence or insertion of an octarepeat still allowed N‐linked glycosylation, but the GFP‐PrPCΔGPI and GFP‐PrPCocta mutant proteins were not complex glycosylated and not cleaved, indicating that the GPI/octa mutants did not reach the mid‐Golgi compartment of the secretory pathway. The transgene expression of the mutant proteins did not affect the ultrastructure of the melanotrope cells nor POMC biosynthesis and processing, or POMC‐derived peptide secretion. Together, our findings reveal the evolutionary conservation of the site of metabolic cleavage and the importance of the presence of the GPI anchor and the absence of the octarepeat in Xenopus PrPC for its correct biosynthesis. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007.
Micropatterning of 2D colloidal crystals using area‐selective immobilization of particles by laser beam irradiation onto azopolymer surface
Authors: Kato Takahiro , Tawata Masahiro , Shimoyama Hiroshi , Ikawa Taiji , Watanabe Osamu
Published: February 2007

We proposed a technique which arranges particles in a regular two‐dimensional array on an azopolymer surface, followed by immobilizing them in an arbitrary pattern on the surface, and studied its prospect. Azopolymer has the two properties of being able “to form a surface relief structure” and “to immobilize particles in the surface” by light irradiation. First, the former characteristic was used to form a periodic two‐dimensional relief pattern template on an azopolymer surface by two‐beam interference exposure, and the particles were arranged on the surface. Then the latter characteristic was used to selectively immobilize particles by light irradiation, and unimmobilized particles were removed by washing. As a result, we demonstrated that particles could be arranged in a regular two‐dimensional array in a square structure and a hexagonal structure, and a two‐dimensional photonic crystal waveguide structure could be easily fabricated by the micropatterning of particles. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(3): 1–8, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20307
A force‐reflecting friction‐free bilateral system based on a twin drive control system with torsional vibration suppression
Authors: Ohba Yuzuru , Ohishi Kiyoshi
Published: February 2007

This paper proposes a new friction‐free bilateral system based on twin drive control system considering resonant frequency for bilateral systems. The twin drive system consists of two motors which are coupled by the differential gear. The output torque becomes a different torque of both motors. The nonlinear friction torque of the twin drive system can be easily compensated. However, the resonant frequency and the antiresonant frequency caused by the tensional vibration exist. This paper proposes a new two‐mass model of twin drive system that supresses torsional vibration by state feedback. The proposed control method is applied to the bilateral robot, and the effectiveness of the control method is confirmed by the experimental results. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 72–79, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20355
Numerical electromagnetic analysis on current distribution in building directly hit by lightning
Authors: Miyazaki Satoru , Ishii Masaru
Published: February 2007

Lightning current distribution in a directly hit building is studied by using a simple equivalent circuit and an electromagnetic model. The Numerical Electromagnetics Code (NEC‐4) is employed for numerical electromagnetic analysis. The error in the shunt ratio of lightning current entering wiring, which is calculated using the electromagnetic model, is estimated to be less than 4%. The shunt ratios for lightning current entering the wiring on the top floor and the first floor are largest. Although they are larger for a higher building, they are almost constant if the building struck has more than five floors. They are smaller when there are more vertical conductors, or the length of the wiring is longer. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 9–16, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20449
Dimeric Orsellinic Acid Derivatives: Valuable Intermediates for Natural Product Synthesis
Authors: Drochner Daniel , Hüttel Wolfgang , Bode Silke E. , Müller Michael , Karl Ulrich , Nieger Martin , Steglich Wolfgang
Published: February 2007

Herein we report on the synthesis of dimeric orsellinates by the Ullmann reaction as well as by biomimetic oxidative phenolic coupling. The Ullmann reaction gives the 5,5′‐ and 3,3′‐coupled dimeric orsellinates 9 and 10 regioselectively. Oxidative phenolic coupling reaction of methyl 2‐hydroxy‐4‐methoxy‐6‐methylbenzoate (2) affords the regioisomeric dimeric orsellinates 11 (3,3′), 12 (5,5′) and 13 (3,5′) simultaneously, which can be separated easily by column chromatography. The atropisomers of the 5,5′‐ and 3,3′‐coupled dimers 9 and 10 were partially resolved using chiral column chromatography. Additionally, the enantiomers of 3,3′‐dimeric biaryl 11 could be obtained in pure form by derivatizing racemic 11 with chiral auxiliaries, separating the diastereomers by column chromatography and cleaving the auxiliary groups. Thereby the absolute configuration of the biaryl axis in camphanate ester (M)‐18 could be determined by X‐ray structure analysis. The dimeric orsellinates rac‐10 and (P)‐10 were used for the synthesis of the dimeric dihydroanthracenones 21a–b by a tandem Michael–Dieckmann reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Ethylene oxide: Evidence of human chromosomal effects
Authors: Garry Vincent F. , Hozier John , Jacobs Donald , Wade Richard L , Gray David G.
Published: February 2007

Ethylene oxide is a known mutagen as indicated by short‐term testing in vitro and in vivo. Occupational exposure can occur during ethylene oxide gas sterilization of materials for hospital and other use. To study the problem in a hospital sterilization facility where occupational exposure was suspected, epidemiologic, analytic, and bioassay tools were employed. All persons whose work activities involved some aspect of the sterilization process were considered exposed to the gas. Within this group of symptomatic and asymptomatic individuals, chronic and incidental exposure was documented by clinical history. Sister chromatid exchanges were studied in lymphocytes cultured from exposed individuals as well as comparable controls. Four chronically exposed persons who reported upper respiratory and neurologic symptoms were studied in some detail. This group showed significantly increased sister chromatid exchange at three weeks and again at eight weeks after the last known exposure. Another group of eight persons with fewer complaints studied as late as the ninth week showed significantly increased exchanges. Incidental exposure may also increase sister chromatid exchange. The measured maximum concentration of ethylene oxide in the sterilizer room was 36 ppm (within standards set by the Occupational Safety and Health Administration).
I. Bacterial mutagenicity of particulates from houston air
Authors: Preidecker Barbara Lee Borns
Published: February 2007

This study was designed to examine suspended air particulates from the Houston atmosphere. Airborne particulates were collected using either a hi‐vol sampler (one stage from 0.01 to 25 μm) or an Anderson Cascade Impactor, the five stages of which roughly resemble the human respiratory tract. After organic extraction, the Ames assay was used to determine the mutagenic content of extracts, and the ability to induce prophage was assessed. Also DNA‐repair‐deficient cells were employed to see if the extracts caused DNA damage and what portion of the premutational lesions was repaired in normal cells.

Results indicate that extracts of particulates from Houston air cause a significant number of mutations in bacteria and that the highest frequency of reversions is associated with the smallest particulates. An excision repair system is operative in bacteria which is able to assuage damage done to DNA by these extracts. The extracts did not cause prophage induction.
Mutagenicity of effluents from an experimental fluidized bed coal combustor
Authors: Clark Charles R. , Hobbs Charles H.
Published: February 2007

The fluidized bed combustion of coal, a low‐temperature process capable of utilizing high sulfur and/or low‐grade fuels, may be a viable alternative to conventional coal combustion to meet future energy needs. Studies of an experimental 18‐inch atmospheric fluidized bed combustor (FBC) are aimed at determining potential health risks and environmental acceptability of FBC effluents as compared to effluents from the conventional combustion of coal. Salmonella (Ames) mutagenicity bioassays provide a convenient method for detecting potential mutagens in the process stream, at different locations in the cleanup system, and for evaluating changes in mutagenicity associated with the use of different fuel types and operating conditions. Samples evaluated for mutagenicity include: methylene‐chloride extracts of fly ash collected in bag filters and on high volume filters; methylene‐chloride extracts of size‐selected (respirable) fly ash collected by cascade impactors in the stack breech, and gaseous hydrocarbons collected on Tenax® adsorbent and Soxhlet extracted with n‐pentane. Dose‐dependent mutagenicity in at least three tester strains was detected in six of the nine bag‐filter, fly‐ash extracts; the addition of a metabolic activating system (rat liver S9) either increased, decreased or did not change the direct mutagenicity observed, depending upon the tester strain and extract used. Mutagenicity of respirable fly ash (< 10 μm) increased as the particle size decreased. No mutagenicity was detected in vapor phase hydrocarbons collected from four different positions in the process stream. Mutagenicity was detected in five of seven bag‐filter ash samples obtained from the combustion of Montana Rosebud subbituminous coal. Combustion temperature and other operating conditions which may influence mutagenicity of the fly ash are discussed.
Increases in morphologically abnormal sperm in rats exposed to Co60 irradiation
Authors: Lock L. F. , Soares E. R.
Published: February 2007

We have investigated the effects of testicular exposure to different doses of Co60 radiation on sperm morphology in F‐344 rats. The results indicate that from 150rad to 500 rad gamma irradiation causes statistically significant, dose‐related increases in 1) the percent of morphologically aberrant sperm and 2) the frequency of tailless sperm. Both of these effects were detectable in sperm which were derived from treated spermatid, spermatocytes, and spermatogonial cells. These data indicate that the development of a sperm morphology assay in rats is feasible.
Mutagenicity of pesticides evaluated by means of gene‐conversion in saccharomyces cerevisiae and in aspergillus nidulans
Authors: De Bertoldi M. , Griselli M. , Giovannetti M. , Barale R.
Published: February 2007

Nine pesticides, Afugan, Atrazine, Benomyl, Captan, Daconil, Melthaumittel, Plantvax, Saprol, and Wepsin were tested for the induction of mitotic geneconversion in two different eucaryotic microorganisms, Saccharomyces cerevisae and Aspergillus nidulans. In S cerevisiae the pesticides were also tested after mouse liver microsomal activation; in A nidulans all tests were performed using both resting and germinating conidia. Among the tested pesticides, only Captan revealed a consistent genetic activity, three times greater than that observed with the standard mutagen methylmethansulphonate. This genetic activity of Captan is suppressed after mammalian metabolic conversion. The use of germinating conidia in A nidulans for scoring the induction of mitotic gene‐conversion did not give any further information on the activity of the tested pesticides.
Effect of N‐alkyl chain length on the mutagenicity of N‐nitrosated 1‐naphthyl N‐alkylcarbamates
Authors: Eya Sryan K. , Talcott Ronald E.
Published: February 2007

1‐Naphthyl N‐alkylcarbamates (alkyl = methyl, ethyl, n‐propyl and n‐butyl) were synthesized and then nitrosated with a dichloromethane extract of nitrous acid. The respective N‐nitrosated carbamates were purified and tested for mutagenicity using Salmonella typhimurium LT2 strain TA98 and TA100, and Saccharomyces cerevisiae strain D3. The reactivity of the four nitrosocarbamates toward 4‐(p‐nitrobenzyl)‐pyridine (NBP) was measured in order to assess their strengths as alkylating agents. Bioassay results indicated an inverse relationship between the length of the N‐alkyl chain and the mutagenicity of the N‐nitrosonaphthylcarbamates. The NBP test results indicated an inverse relationship between chemical reactivity and N‐alkyl chain length.
A comparison of the ability of frog and rat S‐9 to activate promutagens in the Ames test
Authors: Cheh Albert M. , Hooper Alan B. , Skochdopole Jill , Henke Craig A. , McKinnell Robert G.
Published: February 2007

A mutagenesis assay employing the frog, Rana pipiens. is currently under development [McKinnell et al, 1979]. A question that must be answered is whether the frog is metaboiically capable of activating a large number of promutagens. The Ames assay offers a simple means of comparing the metabolism of mutagens by different animal species. The Ames response obtained with frog‐liver S‐9 was compared to the response with rat‐liver S‐9, using the following compounds: Benzo(a)pyrene, 7,12‐dimethylbenz(a)anthracene, 2‐aminofluorene, azobenzene, Sudan II, dibutylnitrosamine, hydrazine sulfate, hydroxyethylhydrazine, cyclophosphamide, 1,2‐dichloroethane, tris(2,3‐dibromopropyl)phosphate, diallate, quinoline, quercetin, aflatoxin B 1, emodin, and safrole. Of these compounds, activation by rat S‐9 was observed for all except hydrazine sulfate and safrole. All except Sudan II, 1,2‐dichloroethane, quinoline, and safrole gave positive Ames responses with frog S‐9. In general, the responses with frog S‐9 were quantitatively lower than those obtained with Aroclor‐induced rat S‐9; however, the optimum procedure for frog‐liver induction has not been determined. The response to dichloroethane is very sensitive to the amount of activating enzyme present; it might be positive with optimally induced frog S‐9. Thus, only two of the 15 compounds positive with rat S‐9 were definitely missed when tested with frog S‐9. We feel that the frog assay appears to be promising from the standpoint of false‐negatives.
Use of a rat/hamster S‐9 mixture in the ames mutagenicity assay
Authors: Weinstein David , Katz Marion , Kazmer Sonja
Published: February 2007

Based on the findings of Nagao et al [1978] that phenacetin is negative in the standard Ames test with Aroclor induced rat S‐9 and positive with hamster S‐9, the test was performed with a mixture of rat/hamster S‐9. Phenacetin was mutagenic with the mixture. The activity of the mixture was compared to the rat S‐9 alone with low concentrations of 2‐aminoanthracene (a strong promutagen for Salmonella typhimurium TA 1535, TA 100, TA 1537, and TA 98), nitrosopiperidine (a weak promutagen), and 1, 2 epoxybutane (a weak, directacting mutagen). Except for an increased mutagenic activation by the mixture with nitrosopiperidine the mixture was comparable to the rat S‐9 alone, indicating that replacing rat S‐9 with a rat/hamster S‐9 mixture in the standard Ames test could increase the sensitivity of the test without interfering with rat S‐9 activity.
Genetic analysis of ad‐3 mutants induced by AF‐2 and two other nitrofurans in neurospora crassa
Authors: Ong Tong‐Man , de Serres F. J.
Published: February 2007

Our previous studies have shown that the nitrofurans AF‐2, SQ18506, and FANFT are potent mutagens in Neurospora crassa. The genetic damage produced by these chemicals at the ad‐3 region in N crassa has been characterized by a series of genetic tests. The results of these tests indicate that all three agents induce a high frequency of point mutations and probably a low frequency of multilocus deletions. A comparison of the complementation patterns among the AF‐2‐induced ad‐3B mutants and those induced by other chemical agents indicates that the spectra of intragenic alterations induced by AF‐2 in N crassa are similar to those induced by monofunctional alkylating agents.
Mutagenicity of products from coal gasification and liquefaction in the salmonella/microsome assay
Authors: Schoeny Rita , Warshawsky David , Hollingsworth Lois , Hund Mary , Moore George
Published: February 2007

As a first step in the assessment of their possible bio‐effects, coal‐related materials were tested for mutagenicity in the Salmonella/microsome assay. Of three coal gasification by‐products tested, only a tar was mutagenic for any of four Salmonella strains. The following liquefaction materials were mutagenic for strains TA1538, TA98, and/or TA100: A liquefaction vehicle oil and coal hydrogenation filtered liquid, separated bottoms, vacuum overhead, and vacuum bottoms. Neither powdered coal nor water produced as a by‐product of the hydrogenation process was positive in the Salmonella test. No coal‐related material was mutagenic for the missense mutant TA1535 or for any strain in the absence of metabolic activation provided by rat hepatic homogenates (S9). In all but one instance Aroclor 1254‐induced S9 provided the maximum activation for mutagenesis. Fractionation of all samples was undertaken by serial extraction with organic solvents of increasing polarity (hexane, toluene, methylene chloride, acetonitrile). Highly mutagenic materials were found in fractions of the hydrogenation filtered liquid, vacuum overhead, and vacuum bottoms. Thus far non‐mutagenic samples have not yielded mutagenic components upon fractionation.
Metal mutagens and carcinogens effectively displace acridine orange from DNA as measured by fluorescence polarization
Authors: Richardson Carol L. , Verna James , Schulman Gail E. , Shipp Kevin , Grant Ava D.
Published: February 2007

Several metals are known mutagens and carcinogens. These metals effectively displace acridine orange from DNA when measured by fluorescence polarization. Displacement of 50% of the acridine orange is obtained with less than 0.5 mM concentrations of lead, manganese, cobalt, zinc, cadmium, nickel, iron, copper, and cis‐platinum. In contrast, greater than 80 mM concentrations of lithium, sodium, and potassium are required to displace an equivalent amount of acridine orange from calf thymus DNA. Although cis‐platinum shows the best DNA reactivity in this assay, the interaction between this metal and DNA does not occur immediately, as it does for the other metals tested. These results indicate that the acridine orange displacement assay provides a relative measure of the interaction of metals with DNA, and this DNA reactivity shows a positive correlation with mutagenic/carcinogenic potential.
Chromosome loss induced by procarbazine and diethylnitrosamine in drosophila from matings of treated males with repair‐deficient mei‐9a, mei‐41d5, mus101, and mus104 females
Authors: Zimmering S.
Published: February 2007

Excision repair‐deficient mei‐9a females of Drosophila melanogaster strongly potentiate complete and partial sex chromosome loss induced in the paternal genome by procarbazine and diethylnitrosamine (DEN). Repair‐proficient and postreplication repair‐deficient mei‐41D5, mus101, and mus104 females fail to enhance the frequency of procarbazine‐induced chromosome loss. Whereas mus101 produces a more modest but significantly higher frequency of complete but not partial loss induced by DEN, results are negative for both categories of loss with mei‐41D5, mus104, and repair‐proficient females.
Activity of nitro‐polynuclear aromatic hydrocarbons in the sister chromatid exchange assay with and without metabolic activation
Authors: Nachtman Joseph P. , Wolff Sheldon
Published: February 2007

Nitro‐polynuclear aromatic hydrocarbons are found in diesel particulates. These compounds are potent mutagens in the Ames test. To determine whether nitro‐polynuclear aromatic hydrocarbons are active in a mammalian cell assay, 1‐nitropyrene, 1,8‐dinitropyrene, 2‐nitrofluorene, and 4‐nitrobiphenyl were incubated with cultures of Chinese hamster ovary cells. The frequency of sister chromatid exchange (SCE) was measured in the presence and absence of rat liver S‐9 mix. The addition of S‐9 mix resulted in a large increase in the SCEs induced by all four compounds.
Mutagenicity of HPLC fractions from extracts of aatrex‐treated corn
Authors: Singh I. , Lusby A. F. , McGuire P. M.
Published: February 2007

Crude extracts from maize plants treated with varying concentrations of AAtrex, an s‐triazine herbicide, were tested for the induction of gene conversion in a diploid strain of Saccharomyces cerevisiae heteroallelic at two loci. These extracts were then subjected to analysis by high pressure liquid chromatography (HPLC), and the fractions collected in water, 50% methanol, and 100% methanol were similarly tested. Dose‐dependent convertogenic activity observed in the 50% methanol fractions suggested that the mutagen(s) is recovered in this fraction.
12‐O‐tetradecanoyl‐phorbol‐13‐acetate and its relationship to SCE induction in syrian and chinese hamster cells
Authors: Popescu N. C. , Amsbaugh S. C. , Larramendy M. L. , Dipaolo J. A.
Published: February 2007

12‐O‐Tetradecanoyl‐phorbol‐13‐acetate (TPA) in conditions that produce enhancement of ultraviolet light (UV) and x‐irradiation Syrian hamster embryo cell (HEC) transformation did not cause further increase in the sister chromatid exchange (SCE) frequency induced by UV and x‐irradiation, two physical carcinogens that differ in their mode of DNA interaction and efficiency of SCE induction. Several factors which might influence SCE induction by TPA were studied on HEC and Chinese hamster V79‐4 cells. Heat‐inactivated serum was used because of the possibility that a serum component may interfere with TPA ability to cause SCE. TPA effect on SCE was determined at the first and second division post treatment on cells exposed to different 5‐bromodeoxyuridine (BrdUrd) concentrations. Independent of BrdUrd concentration (1‐10μg/ml medium) and the number of cell divisions post treatment, TPA (0.01‐2μg/ml medium) was ineffective in inducing SCE in exponentially and stationary HEC cultures cultivated in medium supplemented with heat‐inactivated serum. Also, TPA did not increase the SCE frequency in V79‐4 Chinese hamster cells cultured in heat‐inactivated or noninactivated serum. Although SCE induction, a cellular response to carcinogen‐induced DNA damage, may be important for the induction of transformation by environmental agents, the enhancement of transformation frequency caused by TPA occurs without further DNA alterations involved in SCE formation.
Quantitation of the spiral plating technique for use with the salmonella/mammalian microsome assay
Authors: Couse Nancy L , King Jeannette W.
Published: February 2007

Quantitative dose‐response data were obtained using spiral plating in conjunction with the Salmonella/mammalian microsome test. This plating method provides data comparable to that obtained with standard methods. It requires significantly less time and material and generates more information than standard methods.
Effect of ozonation on the mutagenicity of carcinogens in aqueous solution
Authors: Burleson Gary R. , Chambers Thomas M.
Published: February 2007

Ozone is a very strong oxidizing agent that may be used in water purification. The effect of ozonation on the mutagenicity of mutagens and/or carcinogens of diverse chemical structures was evaluated as measured by the Salmonella/microsome assay. The effect of ozonation of 36 mutagens and/or carcinogens has been evaluated and the results of 15 reported here. The mutagenicity of polycyclic aromatic hydrocarbons and aromatic amines was inactivated by ozone treatment, while alkylating agents, nitro aromatics, and nitroso compounds were not affected. Ozonation of hydrazines produced mutagenic intermediates that may be susceptible to base‐catalyzed hydrolysis. Therefore, depending on the chemical present, ozonation may be useful in the treatment of waters containing organic carcinogens, including drinking water, waste‐water effluents, and other aqueous waste materials containing carcinogens.
Studies of the mutagenic response of salmonella typhimurium TA98 to size‐fractionated air particles: Comparison of the fluctuation and plate incorporation tests
Authors: Sorenson W. G. , Whong Wen‐Zong , Simpson Janet P. , Hearl Frank J. , Ong Tong‐Man
Published: February 2007

The high‐volume Andersen sampler was used to study the mutagenic activity of size‐fractionated airborne particles from ambient air in Morgantown, West Virginia. Mutagenicity was studied by the Ames Salmonella assay and the bacterial fluctuation test and was dependent on particle size in both systems, ie, the greatest activity was associated with the smallest particles. Comparison of the two systems was based on identical aliquots of each extract, cells prepared under identical conditions at the same time, and on mutagenic response at a predetermined level of statistical significance (P < 0.05). The results suggest a slight advantage in sensitivity for the Ames test for the air samples under study.
Mutagenic response to ultraviolet light and X‐rays at five independent genetic loci in chinese hamster ovary cells
Authors: Singh Bhag , Gupta Radhey S.
Published: February 2007

The mutagenic response to ultraviolet light and X‐irradiation at a number of well characterized independent genetic loci, viz those conferring resistance to 6‐thioguanine, ouabain, emetine, methylglyoxal (bis) guanylhydrazone (MGBG), and 5,6‐dichlororibofuranosyl benzimidazole (DRB), has been determined. Upon exposure of cells to UV light in the range of 70 to 180 ergs/mm2, the frequency of mutants at all of the above genetic loci increased in a linear dose‐dependent manner. However, some genetic‐locus‐specific differences in response to UV light were observed in these studies. In contrast to UV light, exposure of cells to X‐rays caused a linear dose‐dependent increase in the frequency of mutants at only the thioguanine‐resistant (Thgr) locus, which affects the purine salvage pathway enzyme hypoxanthine‐guanine phosphoribosyltransferase, that is not essential for growth under these conditions. The other genetic loci that affect essential cellular functions (and hence should detect only specific base substitution types of mutations), however, showed no increase in the frequencies of mutants upon X‐irradiation of cells. These results are in accordance with the nature of the genetic lesions which are caused by these agents and the properties of these genetic markers.
Selection of fetal bovine serum for use in the C3H/10T1/2 CL8 cell transformation assay system
Authors: Oshiro Y. , Balwierz P. S. , Piper C. E.
Published: February 2007

The purpose of this communication is to report our experience concerning the variation in cloning efficiency and transformation frequency utilizing C3H/10T1/2 CL8 cells with 23 different lots of fetal bovine sera. These sera were purchased from five different commercial sources. The standard cell transformation assay using 1,000 cells per dish and 3‐methylcholanthrene (7.5 μg/ml) as the transforming agent was performed. The chemical exposure period was 3 days. The cloning efficiency was determined in parallel toxicity tests using 200 cells per dish. Only three out of 23 serum lots supported a strong response in cell transformation. The results indicated that variation in the ability of sera to support cell transformation was not supplier dependent. In addition, our results showed that serum lots exhibiting the best cloning efficiencies did not necessarily support cell transformation. It is apparent that reliance on cloning efficiency alone would be inadequate as a means of selecting a serum lot. We therefore recommend that a complete cell transformation assay be performed when selecting fetal bovine serum for use in this assay.
Genetic effects of 1,2‐dibromo‐3‐chloropropane (DBCP) in drosophila
Authors: Kale P. G. , Baum J. W.
Published: February 2007

Induction of sex‐linked recessive lethal mutations, heritable translocations and genetic crossing‐over were studied in Drosophila melanogaster males treated as adults and as embryos with different concentrations of gaseous DBCP. Adults exposed to 30 ppm/hr of the compound did not produce a significant number of sex‐linked recessive lethal mutations in treated spermatozoa, spermatids, or spermato‐cytes. However, at an exposure of 17.7 ppm/hr, a weak mutagenic effect was observed in embryonic spermatogonia. No translocation was scored in 4032 tested chromosomes from adults treated with 150 ppm/hr. However, a significant number of spermatocytial crossovers were induced after an exposure of 120 ppm/hr.
Complex effects of retinol on the metabolic activation of 2‐aminofluorene
Authors: Balbinder Elias , Stick Sally M. , Sharma Opendra K.
Published: February 2007

It has been reported that vitamin A alcohol (retinol) inhibits the mutagenicity of certain carcinogenic agents requiring metabolic activation by mammalian microsomal enzymes in the Ames Salmonella assay. We have found that the effect of retinol on the mutagenicity of 2‐aminofluorene (2AF), a carcinogen requiring metabolic activation, is complex and dependent both on the ratio of retinol (μg per plate) to S9 (μg of protein per plate), as well as the absolute concentration of retinol. Retinol had no effect on the mutagenicity of 4‐nitro‐o‐phenylenediamine (4NPDA), a direct‐acting mutagen. However, the mutagenicity of 4NPDA was inhibited by S9 and this inhibition was not affected by retinol.
Pesticide‐induced complete and partial chromosome loss in screens with repair‐defective females of drosophila melanogaster
Authors: Woodruff R. C. , Phillips J. P. , Irwin D.
Published: February 2007

Commercial preparation of fungicides (captan and maneb), herbicides (bromacil, paraquat, picloram, and 2,4‐D), and insecticides (carbaryl, chlorpyrifos, dimethoate, DDT, diazinon, carbofuran, and permethrin) were tested for their ability to induce complete and partial chromosome losses in Drosophila melanogaster males. In an attempt to identify the mutagenic activity of pesticides that are toxic in low concentrations in Drosophila, these males were mated with mus‐302 repair‐defective females. The rationale for this mating scheme is based on the repair of genetic damage in Drosophila sperm by maternal enzymes in the zygote, and on the reports that there may be increases in the frequency of recovery of chemically induced chromosome losses in crosses of treated males with mus‐302 females. Verification of the sensitivity of this screen in this study came from significant increases in the frequency of chromosome loss induced by low concentrations of the positive controls. N‐nitrosodimethylamine and methyl methanesulfonate. Of the 13 pesticides, the insecticide chlorpyrifos induced a significant amount of ring‐X chromosome loss. No pesticide induced a significant increase in partial chromosome loss. These results are discussed in relation to the usefulness of repair‐defective mutants in screens for genetic damage in Drosophila and other higher eukaryotes by chemicals that are toxic or cause sterility at low concentrations.