bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, crystal structure and herbicidal activity of mimics of intermediates of the KARI reaction
Authors: Wang Bao‐Lei , Duggleby Ronald G , Li Zheng‐Ming , Wang Jian‐Guo , Li Yong‐Hong , Wang Su‐Hua , Song Hai‐Bin
Published: October 2004

Two mimics of the intermediate in the reaction catalyzed by ketol‐acid reductoisomerase (KARI) were synthesized. Their structures were established on the basis of elemental analyses, IR, 1H NMR and GC/mass detector. The crystal structure of compound 2 was found to be a substituted dioxane, formed by the condensation of two molecules. The two compounds showed some herbicidal activity on the basis of tests using rape root and barnyard grass growth inhibition. However, the herbicidal effect was weaker in greenhouse tests. Copyright © 2004 Society of Chemical Industry
Antifungal activity of limonoids from Khaya ivorensis
Authors: Abdelgaleil Samir AM , Hashinaga Fumio , Nakatani Munehiro
Published: October 2004

Chemical investigation of the diethyl ether extract of the stem bark of Khaya ivorensis A Chev (Meliaceae) afforded ten limonoids of angolensates, ring D‐opened limonoids and mexicanolides. The structures of the limonoids isolated were determined by comparison of their 1H and 13C NMR data with those reported in the literature. These compounds were evaluated for their antifungal activity against the plant pathogenic fungus Botrytis cinerea Pers. Methyl 6‐hydroxyangolensate and 3,7‐dideacetylkhivorin were also tested for their antifungal and antibacterial activities on several fungal and bacterial species. Methyl angolensate and 1,3,7‐trideacetylkhivorin displayed the highest antifungal activity against B cinerea, with respectively 62.8 and 64.0% mycelial growth inhibition at 1000 mg litre−1, and 73.3 and 68.6% mycelial growth inhibition at 1500 mg litre−1. 3,7‐Dideacetylkhivorin showed stronger antifungal and antibacterial activities than methyl 6‐hydroxyangolensate against all of the test fungi and bacteria except Penicillium expansum Link. This is the first report on the antifungal and antibacterial effects of these limonoids. Structure‐antifungal activity relationships of the limonoids isolated are discussed. Copyright © 2004 Society of Chemical Industry
Sorption in reconstituted waxes of homologous series of alcohol ethoxylates and n‐alkyl esters and their effects on the mobility of 2,4‐dichlorophenoxybutyric acid
Authors: Šimáňová Eva , Shi Tuansheng , Schönherr Jörg , Schreiber Lukas
Published: October 2004

Equilibrium sorption of n‐alkyl esters (dimethyl suberate, diethyl suberate, diethyl sebacate, dibutyl suberate and dibutyl sebacate) and monodisperse alcohol ethoxylates (diethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol and octaethylene glycol monododecyl ether) between the reconstituted cuticular waxes of Stephanotis floribunda Brongn (Madagascar jasmine) or Hordeum vulgare L (barley) leaves and an external aqueous receptor solution was determined. Logarithms of the wax/receptor partition coefficient (Kwax/rec) of the n‐alkyl esters increased linearly with the number of C‐atoms. With alcohol ethoxylates, log Kwax/rec decreased linearly with the number of ethylene oxide units. For both groups of compounds, Kwax/rec increased with increasing lipophilicity. The values of Kwax/rec in Stephanotis wax were between 5 and 16 times higher than in barley wax. It is argued that this difference was due to different chemical composition and crystallinity of the waxes. Mobility of [14C]2,4‐dichlorophenoxybutyric acid (2,4‐DB) in reconstituted Stephanotis and barley wax was increased by a factor of 2–8 by both n‐alkyl esters and alcohol ethoxylates. Effects on the mobility of 2,4‐DB were linearly related to the internal concentrations of n‐alkyl esters and alcohol ethoxylates in reconstituted Stephanotis or barley wax. At the same internal concentrations the effect of n‐alkyl esters on the mobility of 2,4‐DB in wax exceeded that of alcohol ethoxylates by between 1 and 2 orders of magnitude. Results are discussed in relation to formulating systemic pesticides. Copyright © 2004 Society of Chemical Industry
Use of promolecular ASA density functions as a general algorithm to obtain starting MO in SCF calculations
Authors: Amat Lluís , Carbó‐Dorca Ramon
Published: October 2004

Atomic shell approximation (ASA) constitutes a way to fit first‐order density functions to a linear combination of spherical functions. The ASA fitting method makes use of positive definite expansion coefficients to ensure appropriate probability distribution features. The ASA electron density is sufficiently accurate for the practical implementation of quantum similarity measures, as was proved in previous published work. Here, a new application of the ASA density formalism is analyzed, and employed to obtain an initial guess of the density matrix for SCF procedures. The number of cycles needed to assess the convergence criterion in electronic energy calculations appears comparable to or less than those obtained by other means. Several molecular structures of different classes, including organic systems and metal complexes, were chosen as representative test cases. In addition, an ASA basis set for atoms Sc‐Kr fitted to an ab initio 6‐311G basis set is also presented. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Hellmann–Feynman theorem near the threshold
Authors: Pupyshev Vladimir I.
Published: October 2004

The features of the spectrum structure are considered for situations where some parameter λ of the N‐electron Hamiltonian reaches the threshold value η under which the discrete energy level falls into the continuous spectrum. The electron density properties are also studied. It is proved that for a sequence of the wave functions converging in energy to the lower bound of the continuous spectrum as λ approaches η the corresponding sequence of the electron densities converges to the density of the (N − 1)‐electron ground state. The results generalize the Hellmann–Feynman theorem for the cases where only the one‐side energy derivatives exist or there is no limiting wave function. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
NANOPACK: Parallel codes for semiempirical quantum chemical calculations of large systems in the sp‐ and spd‐basis
Authors: Berzigiyarov Parvaz K. , Zayets Valentin A. , Ginzburg Ilya Ya. , Razumov Vladimir F. , Sheka Elena F.
Published: October 2004

A parallel implementation of the conventionally used NDDO (MNDO, AM1, PM3, CLUSTER‐Z1) and modified NDDO‐WF (CLUSTER‐Z2) techniques for semiempirical quantum chemical calculations of large molecular systems in the sp‐ and spd‐basis, respectively, is described. The atom‐pair distribution of data over processors forms the basis of the parallelization. The technological aspects of designing scalable parallel calculations on supercomputers (using ScaLAPACK and MPI libraries) are discussed. The scaling of individual algorithms and the entire package was carried out for model systems with 894, 1920, and 2014 atomic orbitals. The package speed‐up provided by different multiprocessor systems involving a cluster of Intel PIII processors, Alpha‐21264‐processor‐built machine MBC‐1000M, and Cray‐T3E is analyzed. The effect of computer characteristics on the package performance is discussed. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Unconventional consideration of the symmetry properties—New techniques and computer codes: Application for high‐temperature superconductors
Authors: Liverts E. Z.
Published: October 2004

The conventional technique for solving the equations of quantum chemistry is extended to the structures possessing certain symmetries. This proposal allows the release of unoccupied electronic states located lower than the ground‐state Fermi level of a specific system. Such states can be treated as “spectral holes.” Application of this technique, in particular, when calculating the electronic structure of the high‐temperature superconductor (HTSC) compound YBa2Cu3O7δ (0 ≤ δ ≤ 1) results in the following. For all versions of the examined charge distributions over a crystal lattice, spectral holes of high spatial localization are found. The “spatial spectral holes” are located mainly at the py‐orbitals of the apex oxygens. These orbitals overlap and form linear chains that are parallel to the known Cu(1)O chains, disappearing when δ is close to 1. One can suppose that the linear chains of the overlapping hole states form a “superconducting channel.” Some other parameters closely related to the critical characteristics of HTSC materials are also calculated. The calculations show that the superconducting channel is broken when the oxygen chain atoms O(1) are removed (δ > 0). © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Molecular dynamics of phase transitions in clusters of alkali halides
Authors: Rodrigues Pedro C. R. , Silva Fernandes Fernando M. S.
Published: October 2004

Molecular dynamics simulations of unconstrained alkali halide clusters with 8, 64, 216, 512, 1000, 1728, 2744, 4096, 5832, and 8000 ions have been carried out using the Born–Mayer–Huggins potential. All the clusters exhibit first‐order melting and freezing transitions. The melting temperature increases with the number of ions and approaches the melting temperature of the bulk. Clusters with a number of ions less than approximately 1000 present hysteresis cycles and practically do not have phase coexistence. Clusters with a number of ions over 1000 present phase coexistence during a significant part of the transition region and hysteresis is progressively eliminated as the clusters size increases. It is suggested that hysteresis is an intrinsic characteristic of small clusters. In the transition regions the calculations have been performed by fixing the total energy of the clusters. It is shown that such a technique provides a better way of analyzing the transition mechanism than the usual procedure of fixing the temperature by ad hoc rescaling the velocities or by using canonical molecular dynamics or Monte Carlo. A detailed analysis of the melting transition is presented. The effects of interfaces and impurities are discussed. A method based on the velocity autocorrelation functions is proposed, in order to determine the molar fraction of the ions present in the solid and liquid phases as well as to produce colored snapshots of the phases in coexistence. The overall agreement of the estimated melting points and enthalpies of melting with the experiment is fairly good. The estimated melting point and enthalpy of melting for KCl in particular are in excellent agreement with the experimental values. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 169–180, 2001
Theoretical study of chiral discrimination in the hydrogen bonding complexes of the hydrazine dimer
Authors: Du Dongmei , Fu Aiping , Zhou Zhengyu
Published: October 2004

In this work, the discrimination of different chiral forms of the hydrazine dimer were investigated using Density Functional Theory (DFT) and second‐order Moller–Plesset Perturbation (MP2) theory at basis set levels from 6‐31g to 6‐31++g(d,p). Four chiral structures were studied. The optimized geometric parameters, interaction energies, and chirodiastatic energy for various isomers at different levels were estimated. Finally, the solvent effects on the geometries of the hydrazine dimers were also investigated using self‐consistent reaction‐field (SCRF) calculations at the B3LYP/6‐31++g(d,p) level. The results indicate that the polarity of the solvent has played an important role in the structures and relative stabilities of different isomers. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Density functional theory and quantum similarity
Authors: Geerlings P. , Boon G. , Van Alsenoy C. , De Proft F.
Published: October 2004

Quantum molecular similarity (QMS), for which the first measures were introduced by Carbó in the early 1980s, has been shown to be an important concept when comparing properties and reactivity of different, albeit mostly related, molecules. In this article we investigate how various subfields of Density Functional Theory (DFT) contribute in their own way to the evaluation and the understanding of QMS, reflecting the combined interest of our group in both domains in recent years. The contribution of computational DFT is easy to pinpoint, as DFT can now be used in the evaluation of electron densities of ever‐increasing quality. When establishing a link between the fundamental(s) of DFT and QMS the role of the shape function turns out to be predominant and an extension of Mezey's Holographic Electron Density Theorem for ρ(r) to the shape function σ(r) is presented. On this basis, similarity in shape is the fundamental issue to be looked at, both globally and locally. As an application, global and local similarity measures were evaluated using the Hirshfeld partitioning technique for the two enantiomers of CHFClBr, giving numerical evidence for the Holographic Electron Density Theorem. As an application of conceptual DFT, similarity indices constructed via DFT based local reactivity descriptors (e.g., local softness) are used to probe the “similarity of reactivity” of a series of peptide isosteres. The use of the autocorrelation function for condensed indices turns out to be a valuable technique to circumvent the orientation‐translation dependence of similarity indices. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
The characteristics of formative assessment in science education
Authors: Bell Beverley , Cowie Bronwen
Published: October 2004

Formative assessment, in this article, is defined as “the process used by teachers and students to recognize and respond to student learning in order to enhance that learning, during the learning.” The findings of a two‐year research project in New Zealand indicate that formative assessment has the following characteristics: responsiveness, sources of evidence, a tacit process, using professional knowledge and experiences, an integral part of teaching and learning, formative assessment is done by both teachers and students, the purposes for formative assessment, the contextualized nature of the process, dilemmas, and student disclosure. © 2001 John Wiley & Sons, Inc. Sci Ed 85:536–553, 2001.
Repeated cocaine administration increases GABAB(1) subunit mRNA in rat brain
Authors: Yamaguchi Mika , Suzuki Toshihito , Abe Shuzo , Baba Atsuomi , Hori Takafumi , Okado Nobuo
Published: October 2004

The effects of a single and repeated administration of cocaine on GABAB receptor subunit mRNA was investigated in rat brain by in situ hybridization. Following a single administration of cocaine, no significant change was observed in any brain regions examined, neither 1 h nor 24 h after administration. During repeated administration of cocaine, behavioral sensitization with increased stereotyped behavior was observed. A significant increase in the level of GABAB(1) mRNA was observed in the nucleus accumbens (11.4%), CA1 field of the hippocampus (16.8%), and thalamus (16.5%) 1 day after repeated administrations of cocaine for 14 consecutive days. The level of mRNA returned to the basal level 1 week after the final injection of repeated cocaine treatment. The observed changes in the mRNA level after the repeated cocaine may imply changes of GABAB(1) subunit in molecular mechanisms which underlie development of behavioral sensitization. Synapse 43:175–180, 2002. © 2002 Wiley‐Liss, Inc.
Studies of the biogenic amine transporters. 10. Characterization of a novel cocaine binding site in brain membranes prepared from dopamine transporter knockout mice
Authors: Rothman Richard B. , Carroll F. Ivy , Morales Marisela , Rowley Daniel L. , Rice Kenner C. , Dersch Christina M. , Donovan David M.
Published: October 2004

Previous work suggested that the cocaine analog [125I]RTI‐55 labels a novel binding site in rat brain membranes, which is not associated with the dopamine (DA), serotonin (5‐HT), or norepinephrine (NE) transporters [Rothman et al. 1995 J Pharmacol Exp Ther 274:385–395]. Here, we tested whether this site is a product of the DA transporter (DAT) gene. We used a T‐antigen knock‐in at the DAT gene that results in an effective DAT knock‐out (KO) confirmed by Southern blot, DAT immunohistochemistry, and [125I]RTI‐55 ligand binding. Brain membranes were prepared from frozen whole brain minus caudate of wild‐type (WT) B6/Sv129, +/+ and −/− (KO) mice. KO mice were used at approximately 23 days of age. Binding surface analysis of [125I]RTI‐55 binding to membranes prepared from the brains of WT mice, with 100 nM citalopram to block binding to the 5‐HT transporter (SERT), revealed two binding sites: the DAT and a second site, replicating previous studies conducted with rat brains. In the absence of the DAT (−/− mice), binding surface analysis demonstrated that [125I]RTI‐55 labeled two sites: the NET and a second site called site “X.” Structure–activity studies of site “X” demonstrated that high‐affinity ligands for the DAT, NET, and SERT have low or negligible affinity for site “X.” The relatively high density of site “X” in brain membranes and the fact that the Ki values of cocaine and cocaethylene for site “X” are in the range achieved in the brain following cocaine administration suggests that site “X” could contribute to the pharmacological or toxicological effects of cocaine. Further progress in delineating the function of site “X” will depend on developing potent and selective agents for this site. Synapse 44:94–105, 2002. Published 2002 Wiley‐Liss, Inc.
Equitable science education in urban middle schools: Do reform efforts make a difference?*
Authors: Hewson Peter W. , Kahle Jane Butler , Scantlebury Kathryn , Davies Darleen
Published: October 2004

A central commitment of current reforms in science education is that all students, regardless of culture, gender, race, and/ or socioeconomic status, are capable of understanding and doing science. The study “Bridging the Gap: Equity in Systemic Reform” assessed equity in systemic reform using a nested research design that drew on both qualitative and quantitative methodologies. As part of the study, case studies were conducted in two urban middle schools in large Ohio cities. The purpose of the case studies was to identify factors affecting equity in urban science education reform. Data were analyzed using Kahle's (1998) equity metric. That model allowed us to assess progress toward equity using a range of research‐based indicators grouped into three categories critical for equitable education: access to, retention in, and achievement in quality science education. In addition, a fourth category was defined for systemic indicators of equity. Analyses indicated that the culture and climate of the case study schools differentially affected their progress toward equitable reform in science education. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 1130–1144, 2001
Connecting school and community with science learning: Real world problems and school–community partnerships as contextual scaffolds*
Authors: Bouillion Lisa M. , Gomez Louis M.
Published: October 2004

A challenge facing many schools, especially those in urban settings that serve culturally and linguistically diverse populations, is a disconnection between schools and students' home communities, which can have both cognitive and affective implications for students. In this article we explore a form of “connected science,” in which real‐world problems and school‐community partnerships are used as contextual scaffolds for bridging students' community‐based knowledge and school‐based knowledge, as a way to provide all students opportunities for meaningful and intellectually challenging science learning. The potential of these scaffolds for connected science is examined through a case study in which a team of fifth‐grade teachers used the student‐identified problem of pollution along a nearby river as an interdisciplinary anchor for teaching science, math, language arts, and civics. Our analysis makes visible how diverse forms of knowledge were able to support project activities, examines the consequences for student learning, and identifies the features of real‐world problems and school–community partnerships that created these bridging opportunities. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 878–898, 2001
Vitamins C and E improve rat embryonic antioxidant defense mechanism in diabetic culture medium
Authors: Zaken Varda , Kohen Ron , Ornoy Asher
Published: October 2004

Background

Diabetes teratogenicity seems to be related to embryonic oxidative stress and the extent of the embryonic damage can apparently be reduced by antioxidants. We have studied the mechanism by which antioxidants, such as vitamins C and E, reduce diabetes‐induced embryonic damage. We therefore compared the antioxidant capacity of 10.5‐day‐old rat embryos and their yolk sacs cultured for 28h in diabetic culture medium with or without vitamins C and E.

Methods

The embryos were cultured in 90% rat serum to which 2mg/ml glucose, 2mg/ml beta hydroxy butyrate (BHOB) and 10μg/ml of acetoacetate were added. Rat embryos were also cultured in a diabetic medium with 25μg/ml of vitamin E and 50μg/ml of vitamin C. Control embryos were cultured in normal rat serum with or without vitamins C and E.

Results

Decreased activity of Cu/Zn superoxide dismutase (SOD) and of catalase (CAT) in the “diabetic” embryos and their yolk sacs, and reduced concentrations of low molecular weight antioxidant (LMWA) were found. Under these conditions we also found a decrease in vitamin C and vitamin E concentrations in the embryos, as measured by HPLC. In situ hybridization for SOD mRNA showed a marked reduction of SOD mRNA in the brain, spinal cord, heart and liver of embryos cultured in diabetic medium in comparison to controls. Following the addition of vitamins C and E to the diabetic culture medium, SOD and CAT activity, the concentrations of LMWA, the levels of vitamin C and E and the expression of SOD mRNA in the embryos and yolk sacs returned to normal.

Conclusions

Diabetic metabolic factors seem to have a direct effect on embryonic SOD gene and perhaps genes of other antioxidant enzymes, reducing embryonic endogenous antioxidant defense mechanism. This in turn may cause a depletion of the LMWA, such as vitamins C and E. The addition of these vitamins normalizes the embryonic antioxidant defense mechanism, reducing the damage caused by the diabetic environment. Teratology 64:33–44, 2001. © 2001 Wiley‐Liss, Inc.
Think international manager, think male: Why are women not selected for international management assignments?
Authors: Harris Hilary
Published: October 2004

Studies of women in international management originating primarily from North America consistently highlight
the lack of women in such positions. This trend continues despite the need for growing numbers of expatriates.
Explanations for this phenomenon have centered on women's personal characteristics, home/family
circumstances, organizational support, and host country nationals' attitudes. This study examines the status
of women in international management from a United Kingdom (UK) perspective. A key finding arising from
the study is the critical influence of selection systems for international assignments where the predominant use
of closed, informal selection processes for international assignments was seen to create unintended gender bias
in recruitment. © 2002 Wiley Periodicals, Inc.
Venezuela
Authors: Otero Isabella , Bastidas Rigoberto
Published: October 2004

Venezuela is entering the year 2002 with a new political and economic context characterized by an almost
complete control of power by the elected President Hugo Chavez and a new national constitution approved in
December 15, 1999. This article gives a brief description of the Venezuelan political, economic, financial, legal,
and regulatory systems and it examines the extent to which the changes brought about by this new political context
affect foriegn investment and business practices in the country. © 2002 Wiley Periodicals, Inc.
Development of the recruitment value proposition for geocentric staffing
Authors: Gowan Mary A.
Published: October 2004

Organizations wanting to use a geocentric staffing strategy need to develop and communicate a value proposition that will attract the most qualified employees. This article provides a framework for understanding how culture affects the value proposition offered. The framework proposes that cultural differences will impact the perception of job and work characteristics, total rewards, and corporate image—the three main components of a recruitment value proposition. International experience is proposed as a moderator of the relationship between cultural differences and these components. Recommendations for organizations based on the framework and for future research are provided. © 2004 Wiley Periodicals, Inc.
Staffing architecture for expatriate assignments to support subsidiary cooperation
Authors: Novicevic Milorad M. , Harvey Michael
Published: October 2004

The purpose of this article is to develop a theory‐based explanation of expatriate staffing system (architecture) supporting subsidiary cooperation in multinational organizations. First, an overview of the factors driving the need for this system to provide a rationale for the use of role theory in the development of four specific expatriate role categories in different assignments is presented. Second, we examine how the associated issues of expatriate dependability and competence are related to this categorization. Third, we outline how the design of appropriate expatriate staffing architecture can help resolve specific conflicting issues in subsidiary cooperation. In conclusion, we discuss specific implications of the proposed framework. © 2004 Wiley Periodicals, Inc.
International knowledge transfers through expatriates
Authors: Riusala Kimmo , Suutari Vesa
Published: October 2004

International knowledge transfer processes and related internal stickiness factors have recently been targets of increasing research interest. However, the role of expatriate managers in these international knowledge transfers is not well understood. The objectives of the present study were (1) to analyze what kind of knowledge is transferred within MNCs and what is the role of expatriates in these transfer processes and (2) develop a theoretical framework on internal stickiness factors faced by the expatriates involved in the knowledge transfer processes on the basis of the literature, and test it empirically. The findings indicate that the role of expatriate managers was very central in the transfer processes. Furthermore, support was received for the theoretical framework of internal stickiness factors. © 2004 Wiley Periodicals, Inc.
Structure–activity relationships for gene activation oestrogenicity: Evaluation of a diverse set of aromatic chemicals
Authors: Schultz T. Wayne , Sinks Glendon D. , Cronin Mark T. D.
Published: October 2004

Structure–activity relationships for oestrogenicity were developed based on 120 aromatic chemicals evaluated in the Saccharomyces cerevisiae‐based Lac‐Z reporter assay. Relative gene activation was compared to 17β‐estradiol and varied over eight orders of magnitude. Analysis of the data compared to 17β‐estradiol identified three structural criteria that were related to xenoestrogen activity and potency: (1) the hydrogen‐bonding ability of the phenolic ring mimicking the A‐ring, (2) a hydrophobic centre similar in size and shape to the B‐ and C‐rings, and (3) a hydrogen‐bond donor mimicking the 17β‐hydroxyl moiety of the D‐ring, especially with an oxygen‐to‐oxygen distance similar to that between the 3‐ and 17β‐hydroxyl groups of 17β‐estradiol. Binding data were segregated into activity clusters including strong, moderate, weak, and detectable gene expression, and those compounds that were inactive. The hydrogen‐bonding ability of hydroxy group in the 3‐position on 17β‐estradiol was observed to be essential for gene activation. Compounds with a 4‐hydroxyl substituted benzene ring and a hydrophobic moiety of size and shape equivalent to the B‐ring of 17β‐estradiol were generally observed to be weakly active compounds. Moderately active compounds have a 4‐hydroxyl substituted benzene ring with a hydrophobic moiety equivalent in size and shape to the B‐ and C‐ring of 17β‐estradiol, or have a high hydrogen‐bond donor capacity owing to the presence of halogens on a nonphenolic ring. Strongly active compounds, similar to 4,4′‐diethylethylene bisphenol (DES), possess the same hydrophobic ring structure as described for moderately active compounds and an additional hydroxyl group with an oxygen‐to‐oxygen distance close to that exhibited by the 3‐ and 17‐hydroxyl groups of 17β‐estradiol. © 2002 by Wiley Periodicals, Inc. Environ Toxicol 17: 14–23, 2002
Factors affecting women's preference for type of prenatal screening test for chromosomal anomalies
Authors: Spencer K. , Aitken D.
Published: October 2004

Objective

To ascertain, by means of a questionnaire, women's preferences for four different approaches to prenatal screening for Down syndrome.

Methods

Women attending antenatal clinics at six UK maternity units were asked to put in order of preference four different approaches to screening for Down syndrome all of which had the same false positive rate of 5%. The options were: (1) first‐trimester testing, 90% detection of Down syndrome with results available in 1 h at one‐stop clinics for the assessment of risk (OSCAR); (2) first‐trimester testing, 90% detection and results available within 2–3 days (combined screening); (3) first‐trimester testing plus second‐trimester testing, 93% detection and results available within 2–3 days of second test (integrated testing); (4) second‐trimester testing, 75% detection and results available within 2–3 days.

Results

Over 1100 women attending antenatal clinics at six maternity units across the UK returned the questionnaire. A total of 75% of women selected a first‐trimester test (option 1 or option 2) as their first choice with 68.2% expressing a preference for the OSCAR approach and a further 6.8% for combined screening. Twenty‐four percent of women opted for integrated testing as their first choice with only 1% expressing a preference for second‐trimester screening.

Conclusions

A first‐trimester test is preferred by the majority of women over a test with marginally higher detection rate that delivers results later in pregnancy. Timing and rapid reporting of results appear to influence women's choice of test. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Sterilisation of intellectually disabled women
Authors: Servais L. , Leach R. , Jacques D. , Roussaux J.P.
Published: October 2004

Objective

To point out the proportion of intellectually disabled women (IDW) who are sterilised, and the medical and social factors associated with an increased probability to be sterilised.

Study design

A population-based study among 97% of IDW aged 18–46, attending government-accredited institutions in the region of Brussels-Capital and the province of Walloon Brabant (Belgium).

Results

Among the IDW included in this study, 22.2% are sterilised, which is superior to the 7% in the general Belgian population. Factors associated with an increased probability to be sterilised are: living in an institution, having a higher intellectual quotient (IQ), being enrolled in an institution where sexual intercourse is authorised and attending an institution where contraception is required. The last three factors are significant only among women living in institutions and the last two, only in women with severe disability. Among IDW using contraception, no factor was associated with a greater probability to be sterilised.

Conclusion

The prevalence of sterilisation among IDW is three times higher than that in the Belgian population and it is mainly correlated with factors related to the institution where these women live, especially the severely disabled.
Forest edge in the Brazilian Atlantic forest: drastic changes in tree species assemblages
Authors: Oliveira Marcondes A. , Grillo Alexandre S. , Tabarelli Marcelo
Published: October 2004

In this study we surveyed all trees ≥10 cm diameter at breast height within 20 0.1 ha plots in a 3,500 ha forest fragment, surrounded by sugar cane fields, of the Brazilian Atlantic forest to compare tree species assemblages at the forest edge (0–100 m into forest) vs forest interior (>200 m). Plots were perpendicular to the margin. The mean number of tree species was significantly higher in the forest interior (35.4 ± SD 7.1 vs 18.4 ± SD 4.4). In addition, forest edge differed from interior in the proportion of shade-tolerant, emergent, large/very large-fruited species, and large-seeded tree species. Among the 134 tree species recorded, 24% were exclusive to the forest edge and 57% to the forest interior. Our results suggest that both the current system of protected areas and archipelagos of small fragments (1) tend to retain only a subset of the original flora, (2) will converge in terms of floristic and ecological composition (biotic simplification and homogenization), and (3) will lose rare and threatened tree species.
Does selective wood exploitation affect amphibian diversity? The case of An'Ala, a tropical rainforest in eastern Madagascar
Authors: Vallan Denis , Andreone Franco , Raherisoa Vola H. , Dolch Rainer
Published: October 2004

The diversity of amphibians before and after low-level forest exploitation in An'Ala forest in central-eastern Madagascar was compared over the course of 4 years. Neither abundance nor diversity of amphibians generally were significantly affected by low-level selective logging, although the abundance of individual species differed. Mantelline anurans were the most sensitive, in contrast to the tree frogs of the subfamily Boophinae (Mantellidae) and Cophylinae (Microhylidae). The abundance of Mantellinae anurans decreased by 15.8% after logging, whereas Boophinae and Microhylidae anurans increased by 12.1% and 3.7%, respectively. In general, species strongly tied to rainforest habitat showed a non-significant 10.1% decrease in abundance after logging. It appears therefore that amphibians are relatively resilient to a low-level of forest exploitation and their diversity is apparently not affected, at least in the short-term. This and other studies have, however, shown that logging commonly results in a shift in species composition, with species typical of pristine rainforests being replaced by species adapted to secondary habitats.
Hunting of large mammals and pheasants in the Indian western Himalaya
Authors: Kaul Rahul , Hilaluddin  , Jandrotia J.S. , McGowan Philip J.K.
Published: October 2004

We conducted a survey in the western Himalaya of India to assess animal extraction patterns. Data on animal species and their extraction patterns, their importance to the respondents, and reasons and methods of hunting were collected using structured questionnaires. Twenty-three species of large mammals and Galliformes were present in the area, 18 of which were hunted around at least one village. Of special concern were several threatened species that were hunted around most villages were they occurred, although the impact of removal on wild populations is not clear. The main reason for hunting was to supplement animal protein, although some animals were also killed for sale of meat and their parts. The establishment of community-managed forests has not had an impact on extraction rates. Assessment of the impact of hunting on the threatened species in particular is urgently required.
The current status of the Hainan black-crested gibbon Nomascus sp. cf. nasutus hainanus in Bawangling National Nature Reserve, Hainan, China
Authors: Wei Wu , Wang Xiaoming , Claro Francoise , Ding Youzhong , Souris Anne-Camille , Wang Chundong , Wang Changhe , Berzins Rachel
Published: October 2004

The Hainan black-crested gibbon Nomascus sp. cf. nasutus hainanus is on the verge of extinction. Following studies in the late 1980s and early 1990s only limited observations were made of the remaining population in the Bawangling National Nature Reserve on Hainan Island, China, and the most optimistic estimation of the population size was 23 individuals. To determine the present status of this gibbon, we surveyed the western part of the Reserve, from where the gibbons were previously known, using transects (November–December 2001), listening post (February–April 2002) and interviews with reserve staff (November–December 2001 and February–April 2002). Three groups of gibbons were sighted comprising at least 10–12 individuals including juveniles and infants. A fourth group, possibly comprising 2–7 individuals, was heard but not seen. Compared to an unpublished survey by reserve staff in 2000, the population appears to have decreased. Surveying of this gibbon population will continue, in particular to determine the composition of the one group that was heard but not seen and to carry out a survey of the eastern part of the Reserve to determine whether or not any gibbons survive there. The Forestry Bureau of Hainan is applying to the Central Government for an enlargement of the area of the reserve and more staff to help prevent illegal poaching and logging.
Divine providence, simple foreknowledge, and the ‘Metaphysical Principle’
Authors: ROBINSON MICHAEL D.
Published: October 2004

In this essay, I challenge David P. Hunt's defence of the utility of simple foreknowledge for divine providence against the ‘Metaphysical Principle’. This principle asserts that circular causal loops are impossible. Hunt agrees with this principle but maintains that so long as the deity does not use simple foreknowledge in such a way that causal loops unfold, the Metaphysical Principle in not violated. I argue that Hunt's position still allows for the possibility of such causal loops and this itself is a breach of the Metaphysical Principle.
FUNCTIONAL PEARL Functional chart parsing of context-free grammars
Authors: LJUNGLÖF PETER
Published: October 2004

This paper implements a simple and elegant version of bottom-up Kilbury chart parsing (Kilbury, 1985; Wirén, 1992). This is one of the many chart parsing variants, which are all based on the data structure of charts. The chart parsing process uses inference rules to add new edges to the chart, and parsing is complete when no further edges can be added. One novel aspect of this implementation is that it doesn't have to rely on a global state for the implementation of the chart. This makes the code clean, elegant and declarative, while still having the same space and time complexity as the standard imperative implementations.
FUNCTIONAL PEARL On tiling a chessboard
Authors: BIRD RICHARD S.
Published: October 2004

Teacher: Good morning class. Today I would like you to construct a program for finding out how many ways a chessboard can be tiled with dominoes. For those who don't play games, a chessboard is a 8×8 board divided into 64 squares, and a domino is a 2×1 tile which can cover two squares of the board either vertically or horizontally. For example, a 2×2 board can be covered with two dominoes in exactly two ways, with both dominoes horizontal or both vertical.
FUNCTIONAL PEARL Type-safe cast
Authors: WEIRICH STEPHANIE
Published: October 2004

Comparing two types for equality is an essential ingredient for an implementation of dynamic types. Once equality has been established, it is safe to cast a value from one type to another. In a language with run-time type analysis, implementing such a procedure is fairly straightforward. Unfortunately, this naive implementation destructs and rebuilds the argument while iterating over its type structure. However, by using higher-order polymorphism, a casting function can treat its argument parametrically. We demonstrate this solution in two frameworks for ad-hoc polymorphism: intensional type analysis and Haskell type classes.
Lateral neuron–glia interactions steer the response of axons to the Robo code
Authors: KINRADE EDWARD F.V. , HIDALGO ALICIA
Published: October 2004

Glia are required for axon pathfinding along longitudinal trajectories, but it is unknown how this relates to the molecular paradigm of axon guidance across the midline. Most interneuron axons in bilateral organisms cross the midline only once. Preventing them from recrossing the midline requires the expression of Robo receptors on the axons. These sense the repulsive signal Slit, which is produced by the midline. The lateral positioning of longitudinal axons depends on the response to Slit by the combination of Robo receptors expressed by the axons, on selective fasciculation, and on longitudinal (lateral) glia. Here, we analyse how longitudinal glia influence reading of the ‘Robo code’ by axons. We show that whereas loss of robo1 alone only affects the most medial axons, loss of both glial cells missing (gcm) and robo1 causes a severe midline collapse of longitudinal axons, similar to that caused by the loss of multiple Robo receptors. Furthermore, whereas ectopic expression of robo2 is sufficient to displace the medial MP2 axons along a more lateral trajectory, this does not occur in gcm–robo1 double-mutant embryos, where axons either do not extend at all or they misroute exiting the CNS. Hence, lateral neuron–glia interactions steer the response of axons to the Robo code.
Overexpression of c-MYC promotes an undifferentiated phenotype in cultured astrocytes and allows elevated Ras and Akt signaling to induce gliomas from GFAP-expressing cells in mice
Authors: LASSMAN ANDREW B. , DAI CHENGKAI , FULLER GREGORY N. , VICKERS ANDREW J. , HOLLAND ERIC C.
Published: October 2004

The c-MYC protooncogene is overexpressed in the most malignant primary brain tumor, glioblastoma multiforme (GBM), and has been correlated with the undifferentiated character of several cell types. However, the role of Myc activity in the generation of GBMs is not known. In this report, we show that gene transfer of c-MYC to GFAP-expressing astrocytes in vitro promotes the outgrowth of GFAP-negative, nestin-expressing cells with progenitor-like morphology, growth characteristics and gene-expression pattern. In addition, gene transfer of c-MYC to GFAP-expressing astrocytes in vivo induces GBMs when co-expressed with activated Ras and Akt. Without c-MYC, Ras+Akt induces GBMs from nestin-expressing CNS progenitors but is insufficient in GFAP-expressing differentiated astrocytes. The ability of Myc activity to enhance the oncogenic effects of Ras+Akt appears to be limited to GFAP-expressing astrocytes because nestin-expressing progenitors show no increase in GBM formation with the addition of MYC to Ras+Akt. These studies indicate that one role of MYC activity in the formation of gliomas might be to either promote or reinforce an undifferentiated phenotype required for glioma cells to respond to the oncogenic effects of elevated Ras and Akt activity.
The natural history of neuroglia: an agenda for comparative studies
Authors: BULLOCK THEODORE HOLMES
Published: October 2004

Neuroglia, which are the non-neuronal cells of the nervous system, except for meninges and vasculature with its endothelium, blood vessel walls and relatively rare smooth muscle cells, have received much attention in mammalian investigations and occupy a voluminous literature.
Prostaglandin E2 metabolism is activated in Schwann cell lines derived from human NF1 malignant peripheral nerve sheath tumors
Authors: DEADWYLER GAIL D. , DANG IAN , NELSON JULIE , SRIKANTH MAYA , DE VRIES GEORGE H.
Published: October 2004

Malignant peripheral nerve sheath tumors (MPNSTs) are characteristic of Neurofibromatosis type 1 (NF1), a human genetic disorder affecting approximately 1 in 3000 individuals. The absence of neurofibromin in Schwann cells results in hyperactivation of Ras, which contributes to Schwann cell hyperplasia. However, additional intracellular abnormalities in Schwann cells might contribute to the malignancy. We now report that cell lines derived from MPNSTs secrete elevated levels of prostaglandin E2 (PGE2), express higher levels of phosphorylated mitogen-activated protein kinase (MAPK), phosphorylated cytosolic phospholipase A2 (cPLA2) and cyclooxygenase 2 (COX-2) when compared to normal adult human Schwann cells (nhSCs). PCR analysis reveals that NF1 MPNST cell lines express mRNA for both EP2 and EP4 prostaglandin E2 receptors, whereas nhSCs express only the EP4 receptor. COX-2 inhibitors and PGE2 receptor antagonists decrease the proliferation of MPNST cell lines. These results indicate that prostaglandin metabolism is activated in MPNSTs and might contribute to tumor growth in NF1.
Phase partitioning and solubility of iron in natural seawater controlled by dissolved organic matter
Authors: Chen Min , Wang Wen‐Xiong , Guo Laodong
Published: October 2004

The phase partitioning and solubility of Fe as well as its relationship with marine dissolved organic matter (DOM) in different natural seawater and phytoplankton cultures were examined using radiotracer and ultrafiltration techniques to better understand Fe biogeochemical cycling and its biological availability in the ocean. Fe solubility in seawaters was related to the filter's cutoff, with the Fe solubility in the <3 × 103 amu fraction being about one third of that in the <10 × 103 amu filtrate. The Fe solubility decreased from estuarine to coastal to oceanic seawater and then to DOM‐free seawater. There was a significant linear relationship between Fe solubility or [FeL] concentration and the dissolved organic carbon concentration for the seawater of different origins tested, suggesting that Fe solubility was largely controlled by the amount of dissolved organic matter. In addition, Fe solubility was significantly enhanced by the presence of fresh phytoplankton exudates, indicating that the nature of organic ligands also plays an important role in controlling the Fe solubility in seawater. Most of the Fe‐bound organic ligands were in the size fraction <10 × 103 amu and decreased from the estuarine to the coastal and then to the oceanic seawater. Among the standard macromolecular organic compounds examined, siderophores (deferoxamine mesylate and ferrichrome) showed the highest binding capacity for Fe, and carrageenan (a high molecular weight–sulfated acid polysaccharide) also slightly increased Fe solubility. Complexation of organic ligands with Fe appeared to be Fe‐specific or Fe preferential. Our results highlight quantitatively the importance of DOM in controlling Fe solubility in seawater. Further studies are needed to elucidate the interrelationship between the biogeochemical cycles of Fe and the chemistry of DOM in the ocean.