bluuebunny/crossref_metadata_2025 huggingface dataset:
Origin of the π‐Facial Stereoselectivity in the Addition of Nucleophilic Reagents to Chiral Aliphatic Ketones as Evidenced by High‐Level Ab Initio Molecular‐Orbital Calculations
Authors: Takahashi Osamu , Yamasaki Katsuyoshi , Kohno Yuji , Ueda Kazuyoshi , Suezawa Hiroko , Nishio Motohiro
Published: November 2006

Ab initio molecular‐orbital (MO) calculations were carried out, at the MP2/6‐311++G(d,p)//MP2/6‐31G(d) level, to investigate the conformational Gibbs energy of alkyl 1‐cyclohexylethyl ketones, cyclo‐C6H11CHCH3COR (R=Me, Et, iPr, and tBu). In each case, one of the equatorial conformations was shown to be the most stable. Conformers with the axial CHCH3COR group were also shown to be present in an appreciable concentration. Short CH⋅⋅⋅CO and CH⋅⋅⋅OC distances were found in each stable conformation. The result was interpreted on the grounds of CH⋅⋅⋅π(CO) and CH⋅⋅⋅O hydrogen bonds, which stabilize the geometry of the molecule. The ratio of the diastereomeric secondary alcohols produced in the nucleophilic addition to cyclo‐C6H11CHCH3COR was estimated on the basis of the conformer distribution. The calculated result was consistent with the experimental data previously reported: the gradual increase in the product ratio (major/minor) along the series was followed by a drop at R=tBu. The energy of the diastereomeric transition states in the addition of LiH to cyclo‐C6H11CHCH3COR was also calculated for R=Me and tBu. The product ratio did not differ significantly in going from R=Me to tBu in the case of the aliphatic ketones. This is compatible with the above result calculated on the basis of the conformer distribution. Thus, the mechanism of the π‐facial selection can be explained in terms of the simple premise that the geometry of the transition state resembles the ground‐state conformation of the substrates and that the nucleophilic reagent approaches from the less‐hindered side of the carbonyl π face.
Quantification of intracellular homocysteine by stable isotope dilution liquid chromatography/tandem mass spectrometry
Authors: Huang Yuehua , Lu Zhi‐Yong , Brown Karen S. , Whitehead Alexander S. , Blair Ian A.
Published: November 2006

A precise and accurate stable isotope dilution liquid chromatography/tandem mass spectrometry method for the analysis of intracellular homocysteine has been developed. An internal standard, [2H8]‐homocystine, was added to cell pellets from EA.hy 926 cells grown in culture under low and high folate concentrations. d,l‐dithiothreitol was used to reduce cellular homocystine to homocysteine. Cellular proteins were precipitated by the addition of formic acid in acetonitrile. After centrifugation, a portion of the supernatant was analyzed by liquid chromatography/tandem mass spectrometry. Using a Supelcosil cyano column with an Applied Biosystems API 4000 triple quadrupole mass spectrometer, the SRM transitions for homocysteine (m/z 136 to m/z 90) and [2H4]‐homocysteine (m/z 140 to m/z 94) were monitored. The method was validated by conducting five replicate analyses on three different days at four different concentrations (concentrations at the lower limit of quantitation and expected lower quartile, mid‐range and upper quartile). The limit of detection was 2 ng/106 EA.hy 926 cells. Using this method, the intracellular homocysteine concentration in EA.hy 926 cells ranged from 10 to 36 ng/106 cells. Copyright © 2006 John Wiley & Sons, Ltd.
Thermo‐poro‐mechanical properties of clayey gouge and application to rapid fault shearing
Authors: Sulem J. , Lazar P. , Vardoulakis I.
Published: November 2006

In this paper, the mechanism of fault pressurization in rapid slip events is analysed on the basis of a complete characterization of the thermo‐poro‐mechanical behaviour of a clayey gouge extracted at 760 m depth in Aigion fault in the active seismic zone of the Gulf of Corinth, Greece. It is shown that the thermally collapsible character of this clayey gouge can be responsible for a dramatic reduction of effective stress and a full fluidization of the material. The thickness of the ‘ultra‐localized’ zone of highly strained material is a key parameter that controls the competing phenomena of pore pressure increase leading to fluidization of the fault gouge and temperature increase leading to pore‐fluid vapourization. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of the nitration site of insulin by peroxynitrite
Authors: Chi Quan , Huang Kaixun
Published: November 2006

Our previous investigation indicated that insulin can be nitrated by peroxynitrite in vitro. In this study, the preferential nitration site of the four tyrosine residues in insulin molecule was confirmed. Mononitrated and dinitrated insulins were purified by RP‐HPLC. Following reduction of insulin disulfide bridges, Native‐PAGE indicated that A‐chain was preferentially nitrated. Combination of enzymatic digestion of mononitrated insulin with endoproteinase Glu‐C, mass spectrometry confirmed that Tyr‐A14 was the preferential nitration site when insulin was treated with peroxynitrite. Tyr‐A19, maybe, was the next preferential nitration site. According to the crystal structure, Tyr‐B26 between the two tyrosine residues in insulin B‐chain was likely easier to be nitrated by peroxynitrite. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Vibrational properties of GaP and GaP1–xNx under hydrostatic pressures up to 30 GPa
Authors: Jackson M. P. , Halsall M. P. , Güngerich M. , Klar P. J. , Heimbrodt W. , Geisz J. F.
Published: November 2006

We report on Raman scattering of the vibrational modes of GaP and the dilute nitride ternary GaP0.979N0.021 under hydrostatic pressures of up to 30 GPa. We measured the pressure induced shift of the TO and LO modes of GaP up to the phase transition (I–II) and determined mode Grüneisen parameters of 1.12 and 0.98. The phase transition was observed near to 24.5 GPa. We have also studied the dependence of the vibrational spectrum of the GaP0.979N0.021 up to 20 GPa. The zincblende optical phonons of the ternary alloy show great similarities to those of binary GaP, with no significant changes to the Grüneisen parameters or the phase transition. The pressure‐induced shift of local nitrogen mode frequency in GaP0.979N0.021 was studied up to 10 GPa and found to be considerably larger than that of the phonon modes in GaN, indicating that the local mode does not show a GaN‐like behaviour under pressure. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Au nanolayers deposited on polyethyleneterephtalate and polytetrafluorethylene degraded by plasma discharge
Authors: Švorčík V. , Siegel J. , Slepička P. , Kotál V. , Švorčíková J. , Špirková M.
Published: November 2006

Polyethyleneterephtalate (PET) and polytetrafluorethylene (PTFE) foils were modified by plasma discharge. The effect of plasma modification on polymer surface wettability and on properties of gold coatings were studied as a function of time from plasma exposure (aging time) and polymer substrate temperature. Thickness, sheet resistance, and surface topology of gold layers were studied. Aging of the plasma‐exposed samples is accompanied by increase in contact angle, which is explained by rearrangement of the polymer segments in the polymer surface monolayer, and a decrease in the concentration of polar groups. The aging also leads to a decline in surface roughness Ra measured by atomic force microscopy (AFM). Under deposition conditions, comparable thicknesses of deposited Au layers were prepared on pristine PET and plasma‐treated PET and PTFE samples. The thinnest Au layers were evaporated onto pristine PTFE. The sheet resistance decreases with increasing thickness of Au layer. Plasma treatment leads to an increase of PTFE surface roughness, which becomes even more pronounced after Au deposition. A higher roughness shows that the PET samples are deposited with the Au layer at temperatures above the glassy transition temperature Tg. Copyright © 2006 John Wiley & Sons, Ltd.
Biology teachers' attitudes toward and use of Indiana's evolution standards
Authors: Donnelly Lisa A. , Boone William J.
Published: November 2006

This study examines the relationship between biology teachers' evolution teaching practices and their regard and use of Indiana state evolution standards. A survey developed by the authors contained five subscales: use of standards; attitude toward standards; attitude toward evolution standards; evolution teaching practices; and demographic information. This survey was administered to 229 Indiana biology teachers. Data were analyzed using the Rasch model to convert Likert rating scale data into ratio data used for parametric analyses. Correlation analysis revealed significant relationships between use of standards and attitude toward standards, attitude toward standards and evolution teaching practices, and attitude toward evolution standards and days teaching evolution. These findings suggest practical relationships between standards use, teachers' regard of standards, and evolution teaching practices. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 236–257, 2007
Sonographic detection of fetal cerebellar cavernous hemangioma with in‐utero hemorrhage leading to cerebellar hemihypoplasia
Authors: Lerner A. , Gilboa Y. , Gerad L. , Malinger G. , Kidron D. , Achiron R.
Published: November 2006

We report the prenatal diagnosis of cerebellar cavernous angioma. Ultrasound examination at 21 weeks' gestation showed a hyperechogenic lesion measuring 12 mm in diameter, occupying most of the right cerebellar hemisphere. At 24 weeks' gestation, significant hypoplasia of the right hemisphere was diagnosed, and the pregnancy was terminated. Pathological evaluation of the lesion revealed extensive hemorrhaging and a rich network of dilated vessels and small capillaries. The right cerebellar lobe was hypoplastic and covered with blood clots. Cerebral cavernous malformation should be considered in the differential diagnosis of hyperechogenic lesions in the fetal cerebellum. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Malignant melanomas of the nasolacrimal duct
Authors: Esteban F , González-Pérez J M , Benaixa J P , Redondo M , Nevado M , López-Garrido J , Piñero A
Published: November 2006

Two patients with a history of epistaxis who were both found to have a nasolacrimal duct melanoma are presented. A literature review revealed that no previous cases of primary nasolacrimal duct melanoma have been reported. Current therapeutic modalities are discussed.
Multiply antibiotic-resistantVibrio choleraeO1 biotype El Tor strains emerge during cholera outbreaks in Zambia
Authors: MWANSA J. C. L. , MWABA J. , LUKWESA C. , BHUIYAN N. A. , ANSARUZZAMAN M. , RAMAMURTHY T. , ALAM M. , BALAKRISH NAIR G.
Published: November 2006

Antibiotic resistance data, made available from laboratory records during eight cholera outbreaks between 1990 and 2004 showedVibrio choleraeserogroup O1 to have a low level of resistance (2–3%) to tetracycline during 1990–1991. Resistance increased for tetracycline (95%), chloramphenicol (78%), doxycycline (70%) and trimethoprim–sulphamethoxazole (97%) in subsequent outbreaks. A significant drop in resistance to tetracycline and chloramphenicol followed the adoption of a national policy to replace tetracycline with erythromycin for treating cholera. Sixty-nine strains from cholera outbreaks in Zambia between 1996 and 2004, were examined for antibiotic resistance and basic molecular traits. A 140 MDa conjugative, multidrug-resistant plasmid was found to encode tetracycline resistance in strains from 1996/1997 whereas strains from 2003/2004 were resistant to furazolidone, but susceptible to tetracycline, and lacked this plasmid. PCR revealed 25 of 27 strains from 1996/1997 harboured theintl1class 1 integron but lacked SXT, a conjugative transposon element. Similar screening of 42 strains from 2003/2004 revealed all carried SXT but not theintl1class 1 integron. All 69 strains, except two, one lackingctxAand the otherrstRand thus presumably truncated in the CTX prophage region, were positive for important epidemic markers namelyrfbO1,ctxA,rstR2, andtcpAof El Tor biotype. Effective cholera management is dependent on updated reports on culture and sensitivity to inform the choice of antibiotic. Since the emergence of antibiotic resistance may significantly influence strategies for controlling cholera, continuous monitoring of epidemic strains is crucial.
Preparation of the Central Tryptophan Moiety of the Celogentin/Moroidin Family of Anti-Mitotic Cyclic Peptides
Authors: Yuen Alexander K. L. , Jolliffe Katrina A. , Hutton Craig A.
Published: November 2006

The central functionalized tryptophan core of the celogentin/moroidin family of cyclic peptides has been prepared. The strategy incorporates a novel preparation of 4-iodobenzaldehyde and employs a Larock annulation as the key step.
Inference for nonlinear dynamical systems
Authors: Ionides E. L. , Bretó C. , King A. A.
Published: November 2006

Nonlinear stochastic dynamical systems are widely used to model systems across the sciences and engineering. Such models are natural to formulate and can be analyzed mathematically and numerically. However, difficulties associated with inference from time-series data about unknown parameters in these models have been a constraint on their application. We present a new method that makes maximum likelihood estimation feasible for partially-observed nonlinear stochastic dynamical systems (also known as state-space models) where this was not previously the case. The method is based on a sequence of filtering operations which are shown to converge to a maximum likelihood parameter estimate. We make use of recent advances in nonlinear filtering in the implementation of the algorithm. We apply the method to the study of cholera in Bangladesh. We construct confidence intervals, perform residual analysis, and apply other diagnostics. Our analysis, based upon a model capturing the intrinsic nonlinear dynamics of the system, reveals some effects overlooked by previous studies.
Hypoxia facilitates Alzheimer's disease pathogenesis by up-regulating
BACE1
gene expression
Authors: Sun Xiulian , He Guiqiong , Qing Hong , Zhou Weihui , Dobie Frederick , Cai Fang , Staufenbiel Matthias , Huang L. Eric , Song Weihong
Published: November 2006

The molecular mechanism underlying the pathogenesis of the majority of cases of sporadic Alzheimer's disease (AD) is unknown. A history of stroke was found to be associated with development of some AD cases, especially in the presence of vascular risk factors. Reduced cerebral perfusion is a common vascular component among AD risk factors, and hypoxia is a direct consequence of hypoperfusion. Previously we showed that expression of the β-site β-amyloid precursor protein (APP) cleavage enzyme 1 (BACE1) gene
BACE1
is tightly controlled at both the transcriptional and translational levels and that increased BACE1 maturation contributes to the AD pathogenesis in Down's syndrome. Here we have identified a functional hypoxia-responsive element in the
BACE1
gene promoter. Hypoxia up-regulated β-secretase cleavage of APP and amyloid-β protein (Aβ) production by increasing
BACE1
gene transcription and expression both
in vitro
and
in vivo
. Hypoxia treatment markedly increased Aβ deposition and neuritic plaque formation and potentiated the memory deficit in Swedish mutant APP transgenic mice. Taken together, our results clearly demonstrate that hypoxia can facilitate AD pathogenesis, and they provide a molecular mechanism linking vascular factors to AD. Our study suggests that interventions to improve cerebral perfusion may benefit AD patients.
Multiple valence superatoms
Authors: Reveles J. U. , Khanna S. N. , Roach P. J. , Castleman A. W.
Published: November 2006

We recently demonstrated that, in gas phase clusters containing aluminum and iodine atoms, an Al
13
cluster behaves like a halogen atom, whereas an Al
14
cluster exhibits properties analogous to an alkaline earth atom. These observations, together with our findings that Al
13
−
is inert like a rare gas atom, have reinforced the idea that chosen clusters can exhibit chemical behaviors reminiscent of atoms in the periodic table, offering the exciting prospect of a new dimension of the periodic table formed by cluster elements, called superatoms. As the behavior of clusters can be controlled by size and composition, the superatoms offer the potential to create unique compounds with tailored properties. In this article, we provide evidence of an additional class of superatoms, namely Al
7
−
, that exhibit multiple valences, like some of the elements in the periodic table, and hence have the potential to form stable compounds when combined with other atoms. These findings support the contention that there should be no limitation in finding clusters, which mimic virtually all members of the periodic table.
The Tim9p/10p and Tim8p/13p Complexes Bind to Specific Sites on Tim23p during Mitochondrial Protein Import
Authors: Davis Alison J. , Alder Nathan N. , Jensen Robert E. , Johnson Arthur E.
Published: November 2006

The import of polytopic membrane proteins into the mitochondrial inner membrane (IM) is facilitated by Tim9p/Tim10p and Tim8p/Tim13p protein complexes in the intermembrane space (IMS). These complexes are proposed to act as chaperones by transporting the hydrophobic IM proteins through the aqueous IMS and preventing their aggregation. To examine the nature of this interaction, Tim23p molecules containing a single photoreactive cross-linking probe were imported into mitochondria in the absence of an IM potential where they associated with small Tim complexes in the IMS. On photolysis and immunoprecipitation, a probe located at a particular Tim23p site (27 different locations were examined) was found to react covalently with, in most cases, only one of the small Tim proteins. Tim8p, Tim9p, Tim10p, and Tim13p were therefore positioned adjacent to specific sites in the Tim23p substrate before its integration into the IM. This specificity of binding to Tim23p strongly suggests that small Tim proteins do not function solely as general chaperones by minimizing the exposure of nonpolar Tim23p surfaces to the aqueous medium, but may also align a folded Tim23p substrate in the proper orientation for delivery and integration into the IM at the TIM22 translocon.
Yeast P4-ATPases Drs2p and Dnf1p Are Essential Cargos of the NPFXD/Sla1p Endocytic Pathway
Authors: Liu Ke , Hua Zhaolin , Nepute Joshua A. , Graham Todd R.
Published: November 2006

Drs2p family P-type ATPases (P4-ATPases) are required in multiple vesicle-mediated protein transport steps and are proposed to be phospholipid translocases (flippases). The P4-ATPases Drs2p and Dnf1p cycle between the exocytic and endocytic pathways, and here we define endocytosis signals required by these proteins to maintain a steady-state localization to internal organelles. Internalization of Dnf1p from the plasma membrane uses an NPFXD endocytosis signal and its recognition by Sla1p, part of an endocytic coat/adaptor complex with clathrin, Pan1p, Sla2p/End4p, and End3p. Drs2p has multiple endocytosis signals, including two NPFXDs near the C terminus and PEST-like sequences near the N terminus that may mediate ubiquitin (Ub)-dependent endocytosis. Drs2p localizes to the trans-Golgi network in wild-type cells and accumulates on the plasma membrane when both the Ub- and NPFXD-dependent endocytic mechanisms are inactivated. Surprisingly, the pan1-20 temperature-sensitive mutant is constitutively defective for Ub-dependent endocytosis but is not defective for NPFXD-dependent endocytosis at the permissive growth temperature. To sustain viability of pan1-20, Drs2p must be endocytosed through the NPFXD/Sla1p pathway. Thus, Drs2p is an essential endocytic cargo in cells compromised for Ub-dependent endocytosis. These results demonstrate an essential role for endocytosis in retrieving proteins back to the Golgi, and they define critical cargos of the NPFXD/Sla1p system.
Reforming the WTO Legal Order for Agricultural Trade: Issues for European Rural Policy in the Doha Round
Authors: Cardwell Michael , Rodgers Christopher
Published: November 2006

European farm policy has undergone radical change in recent years, culminating in the Agenda 2000 reforms to the Common Agricultural Policy agreed in 1999 and then their Mid-Term Review in 2003. In particular, subsidy payments have been substantially ‘decoupled’ from production and switched decisively towards providing income support for farmers under a new ‘single farm payment’ scheme. These reforms have been predicated upon the need to win acceptance for Community farm subsidies in the Doha Round of WTO negotiations. This article examines the new law of the Common Agricultural Policy against the background of the domestic support reduction commitments contained in the 1994 Uruguay Round Agreement on Agriculture. It questions the extent to which the single farm payment scheme fulfils the requirements for ‘green box’ exemption from such commitments. Options for the re-negotiation of the Agreement on Agriculture are discussed, including measures to improve the justiciability of its terms and to exclude discriminatory and trade-distorting domestic support. The article also considers the implications of the recent WTO Appellate Body Decisions inUnited States—Subsidies on Upland Cotton and European Communities-Export Subsidies on Sugar. It concludes that the Community will have difficulty gaining acceptance for its reforms among WTO Members. Whatever the legitimacy of its subsidy regime within the framework of the current Agreement on Agriculture, the emergence of a strong negotiating position among developing countries, posited on opposition to the volume of farm support maintained by the Community and United States, may present even greater obstacles to the conclusion of a new Agreement on Agriculture in the Doha Round.
III. Financial Market Regulation in the Post-Financial Services Action Plan Era
Authors: McMahon Joe , Moloney Niamh
Published: November 2006

After a hectic period of law reform, which has also provoked major governance reforms in the form of significantly increased levels of transparency and market consultation and major institutional innovations (with allied accountability and governance risks), the 1999 Financial Services Action Plan (FSAP)1 has now been completed. It has radically transformed the regulatory landscape for financial services in the EC, and set a seal on the recharacterization of EC financial services law from a minimum harmonization-based market construction regime to a highly interventionist and increasingly sophisti-cated market regulation system. In particular, the coincidence of legislative reform under the FSAP with the development of a new institutional process for law-making, which has rapidly become embedded in the financial market architecture (the Lamfalussy process),2 produced a reform agenda of immense depth and range. The FSAP period has also seen the use and development of a wide range of regulatory tools in EC financial services policy in line with the growing sophistication of the regulatory regime. While disclosure has long been a key policy tool of EC financial services law, the FSAP saw a closer focus on conflict of interest management across the financial sector, on more interventionist controls such as transparency, suitability, and best execution requirements, and on calibrating regulation to different investor profiles and different market risks. This article considers a selection of key recent developments.
In Search of the Uncovered Set
Authors: Miller Nicholas R.
Published: November 2006

This paper pursues a number of theoretical explorations and conjectures pertaining to the uncovered set in spatial voting games. It was stimulated by the article “The Uncovered Set and the Limits of Legislative Action” by W. T. Bianco, I. Jeliazkov, and I. Sened (2004, Political Analysis 12:256—78) that employed a grid-search computational algorithm for estimating the size, shape, and location of the uncovered set, and it has been greatly facilitated by access to the CyberSenate spatial voting software being developed by Joseph Godfrey. I bring to light theoretical considerations that account for important features of the Bianco, Jeliazkov, and Sened results (e.g., the straight-line boundaries of uncovered sets displayed in some of their figures, the “unexpectedly large” uncovered sets displayed in other figures, and the apparent sensitivity of the location of uncovered sets to small shifts in the relative sizes of party caucuses) and present theoretical insights of more general relevance to spatial voting theory.
Arabidopsis CUP-SHAPED COTYLEDON3Regulates Postembryonic Shoot Meristem and Organ Boundary Formation
Authors: Hibara Ken-ichiro , Karim Md. Rezaul , Takada Shinobu , Taoka Ken-ichiro , Furutani Masahiko , Aida Mitsuhiro , Tasaka Masao
Published: November 2006

Overall shoot architecture in higher plants is highly dependent on the activity of embryonic and axillary shoot meristems, which are produced from the basal adaxial boundaries of cotyledons and leaves, respectively. In Arabidopsis thaliana, redundant functions of the CUP-SHAPED COTYLEDON genes CUC1, CUC2, and CUC3 regulate embryonic shoot meristem formation and cotyledon boundary specification. Their functional importance and relationship in postembryonic development, however, is poorly understood. Here, we performed extensive analyses of the embryonic and postembryonic functions of the three CUC genes using multiple combinations of newly isolated mutant alleles. We found significant roles of CUC2 and CUC3, but not CUC1, in axillary meristem formation and boundary specification of various postembryonic shoot organs, such as leaves, stems, and pedicels. In embryogenesis, all three genes make significant contributions, although CUC3 appears to possess, at least partially, a distinct function from that of CUC1 and CUC2. The function of CUC3 and CUC2 overlaps that of LATERAL SUPPRESSOR, which was previously shown to be required for axillary meristem formation. Our results reveal that redundant but partially distinct functions of CUC1, CUC2, and CUC3 are responsible for shoot organ boundary and meristem formation throughout the life cycle in Arabidopsis.
Arabidopsis NRP1andNRP2Encode Histone Chaperones and Are Required for Maintaining Postembryonic Root Growth
Authors: Zhu Yan , Dong Aiwu , Meyer Denise , Pichon Olivier , Renou Jean-Pierre , Cao Kaiming , Shen Wen-Hui
Published: November 2006

NUCLEOSOME ASSEMBLY PROTEIN1 (NAP1) is conserved from yeast to human and was proposed to act as a histone chaperone. While budding yeast contains a single NAP1 gene, multicellular organisms, including plants and animals, contain several NAP1 and NAP1-RELATED PROTEIN (NRP) genes. However, the biological role of these genes has been largely unexamined. Here, we show that, in Arabidopsis thaliana, simultaneous knockout of the two NRP genes, NRP1 and NRP2, impaired postembryonic root growth. In the nrp1-1 nrp2-1 double mutant, arrest of cell cycle progression at G2/M and disordered cellular organization occurred in root tips. The mutant seedlings exhibit perturbed expression of ∼100 genes, including some genes involved in root proliferation and patterning. The mutant plants are highly sensitive to genotoxic stress and show increased levels of DNA damage and the release of transcriptional gene silencing. NRP1 and NRP2 are localized in the nucleus and can form homomeric and heteromeric protein complexes. Both proteins specifically bind histones H2A and H2B and associate with chromatin in vivo. We propose that NRP1 and NRP2 act as H2A/H2B chaperones in the maintenance of dynamic chromatin in epigenetic inheritance.
The effects of cosolutes on protein dynamics: The reversal of denaturant‐induced protein fluctuations by trimethylamine N‐oxide
Authors: Doan‐Nguyen Vicky , Loria J. Patrick
Published: November 2006

The protein stabilizing effects of the small molecule osmolyte, trimethylamine N‐oxide, against chemical denaturant was investigated by NMR spin‐relaxation measurements and model‐free analysis. In the presence of 0.7 M guanidine hydrochloride increased picosecond‐nanosecond dynamics are observed in the protein ribonuclease A. These increased fluctuations occur throughout the protein, but the most significant increases in flexibility occur at positions believed to be the first to unfold. Addition of 0.35 M trimethylamine N‐oxide to this destabilized form of ribonuclease results in significant rigidification of the protein backbone as assessed by 1H‐15N order parameters. Statistically, these order parameters are the same as those measured in native ribonuclease indicating that TMAO reduces the amplitude of backbone fluctuations in a destabilized protein. These data suggest that TMAO restricts the bond vector motions on the protein energy landscape to resemble those motions that occur in the native protein and points to a relation between stability and dynamics in this enzyme.
Marginal adaptation and micro‐porosity of class II restorations of a high copper amalgam and a palladium‐free gallium‐based alloy
Authors: SHAINI F. J. , WAHAB F. K. , ELLAKWA A. E. , SHORTALL A. C. C. , FLEMING G. J. P. , MARQUIS P. M.
Published: November 2006

summary  The aim of the current investigation was to compare the marginal adaptation and internal porosity of a gallium (Ga)‐based alloy (Galloy®) with a high copper amalgam (Permite C DP®) when used in moderately sized conventional class II cavities. Ten dentists placed two restorations of each material in standardized class II cavities in typodont teeth set in a phantom head. The proximal surfaces of the restored teeth were subsequently examined using an optical microscope and colour photographs were taken. The teeth were then serially sectioned before being re‐examined microscopically and re‐photographed. Three dentists rated the photographs of the restorations on two occasions, 2 weeks apart, for marginal adaptation and internal porosity using a six and five point scoring criteria, respectively. Inter‐ and intra‐examiner agreements were assessed with weighted kappa statistics. The Ga‐based alloy exhibited inferior marginal adaptation and a significantly higher level of porosity and internal defects compared with the dental amalgam. Marginal defects were mainly concentrated at the gingival third of the proximal boxes for both alloys. The poor marginal adaptation and extensive internal porosity detected for the Ga‐based alloy was attributed to the difficulty in the alloy condensation related mainly to the ‘stickiness’ of the alloy to the condensers and to the rapid change in the plasticity of the alloy during condensation. This could possibly be a factor in the post‐operative complications reported with the clinical use of this alloy.
Fracture resistance of crowned incisors with different post systems and luting agents
Authors: GU X.‐H. , KERN M.
Published: November 2006

summary  This study evaluated the fracture resistance of crown‐restored incisors with different post‐and‐core systems and luting cements. Fifty intact maxillary central incisors were randomly assigned to five groups of 10 teeth each. Group 1 was restored with fibre posts (Snowpost) luted with an adhesive composite resin cement (Panavia F). Group 2 was restored with titanium alloy posts (Parapost) luted with the resin cement, and Group 3 with titanium alloy posts and a glass‐ionomer cement (Fuji I). Composite cores (Clearfil Photocore) were built up in groups 1, 2 and 3. Group 4 was restored with cast post‐and‐cores luted with the resin cement, and group 5 with the cast post‐and‐cores and the glass‐ionomer‐cement served as a control group. All teeth were restored with metal‐ceramic crowns. After thermal stressing, the specimen was then secured in a universal testing machine. Fracture loads and modes were recorded. One‐way ANOVA and a Tukey test were used to determine significant differences between the failure loads of groups. Chi‐square test was conducted for evaluation of the fracture modes. The fracture loads of groups 1 and 2 were significantly higher than that of the control group (P<0·05). Group 1 had a significantly higher number of repairable fractures than the other four groups (P<0·001). Within the limitations of this study, the results suggest that fibre posts can be recommended as an alternative to cast and prefabricated metallic posts. Composite resin cement cannot significantly improve fracture resistance of metallic post and crown‐restored incisors.
Earliest Eocene (53 Ma) convergence in the Southwest Pacific: evidence from pre‐obduction dikes in the ophiolite of New Caledonia
Authors: Cluzel Dominique , Meffre Sebastien , Maurizot Pierre , Crawford Anthony J.
Published: November 2006

Uncertainty about the timing and location of the initiation of convergence in the western and south‐western Pacific greatly hinders accurate plate tectonic reconstructions of subduction systems in that area. The chemistry and age of dikes intruding mantle peridotite in the ophiolite of New Caledonia infer that subduction‐related magmatism began before 53 Ma. These new results infer that obduction in the south‐west Pacific is unrelated to the reorientation of the Pacific plate motion that occurred c. 43 Ma and confirm new interpretations showing that changes in mantle flow, hotspot and plate motion may have occurred as soon as late Paleocene or early Eocene.
Herbicidal Activity of Stylosanthes guianensis and its Phytotoxic Components
Authors: Khanh T. D. , Hong N. H. , Nhan D. Q. , Kim S. L. , Chung I. M. , Xuan T. D.
Published: November 2006

Stylosanthes guianensis is a popular pasture legume and cover crop. The legume possessed strong allelopathic potential and suppressed spontaneous growth of paddy weeds. In a bioassay, aqueous extract of S. guianensis remarkably inhibited germination and growth of barnyardgrass and monochoria. Application of 1 ton ha−1 upland parts of S. guianensis significantly reduced paddy weed biomass by 80 % and increased rice yield by 40 % when compared with the control. Gas chromatography‐mass spectrometry analysis reveals the presence of several allelochemicals in S. guianensis including phenolic acids, coumarin and long‐chain fatty acids. Stylosanthes guianensis may be used as a source of natural herbicide for reducing the dependency on synthetic herbicides in agricultural production.
Utopias Re-Imagined: A Reply to Panizza
Authors: Motta Sara
Published: November 2006

This article is a reply to Panizza's recent article, ‘Unarmed Utopia Revisited: The Resurgence of Left-of-Centre Politics in Latin America’. It contests the claims that there are no alternatives to market economies and liberal democracy in contemporary Latin America. It does this by disentangling the conceptual assumptions that underlie the analysis presented, which, it argues, construct a loaded dice that makes the conclusions of the arguments seemingly inevitable and objective. It also explores the internal contradictions within the alternative presented. This analysis is developed through the use of critical social theory and with reference to the ‘movements from below’ engaged in the struggle to re-imagine and reconstruct utopias. This involves bringing to the heart of analysis a theoretical orientation in which structures become a series of concrete social relations, not objects, and power is mediated at a variety of spatial levels. It necessitates a conceptualisation of politics, structure and the agents and nature of structural change that expand the boundaries of traditional political science categories. Such conceptual expansion and theoretical repositioning make visible, and politically central, the movements from below normally categorised as marginal in political analysis.
Prime Ministers, Presidentialism and Westminster Smokescreens
Authors: Bevir Mark , Rhodes R. A. W.
Published: November 2006

This article asks, ‘how do practitioners understand the relationship between the prime minister, ministers and the rest of Westminster and Whitehall?’ We focus on three topics. First, we review tales of a Blair presidency. Second, we explore the governance paradox in which people tell tales of a Blair presidency as they recount stories of British governance that portray it as fragmented with several decision-makers. Finally, we argue that this paradox reveals the distorting influence the Westminster model still exerts on many accounts of British politics. It acts as a smokescreen for the changes in executive politics.
Of Time and Causality: A Simple Test of the Requirement of Social Capital in Making Democracy Work in Italy
Authors: McLaren Lauren M. , Baird Vanessa A.
Published: November 2006

Using survey data from The Civic Culture study, this research note revisits the idea that institutional development across the regions of Italy differs because of varying levels of social capital. The findings indicate that – according to the earliest survey data available from Italy – it is unlikely that differences in the development of regional institutions between the North and the South were a result of differences in social capital between the two regions. The article ultimately contends that social capital is likely to be important for institutional (and economic) development, but that (a) it does not appear to be a prerequisite for either and that (b) it can develop far more quickly than expected; this implies that impersonal trust and a participatory culture are not resources that societies must wait for several centuries to acquire, but that perhaps they can be fostered by the development of powerful democratic institutions.
Platelet Glutamate Uptake and Release in Migraine With and Without Aura
Authors: Vaccaro M , Riva C , Tremolizzo L , Longoni M , Aliprandi A , Agostoni E , Rigamonti A , Leone M , Bussone G , Ferrarese C
Published: November 2006

Glutamate may play an important role in the pathogenesis of migraine: glutamate release in the brain may be involved in the development of spreading depression and increased concentrations of this amino acid have been reported in plasma and platelets from migraine patients. Here we assessed platelet glutamate uptake and release in 25 patients affected by migraine with aura (MA) and 25 patients affected by migraine without aura (MoA), comparing the results with a group of 20 healthy matched controls. Both glutamate release from stimulated platelets and plasma concentrations of the amino acid were assessed by high-performance liquid chromatography, and were increased in both types of migraine, although more markedly in MA. Platelet glutamate uptake, assessed as 3H-glutamate intake, was increased in MA, while it was reduced in MoA with respect to the control group. These results support the view that MA might involve different pathophysiological mechanisms from MoA and, specifically, up-regulation of the glutamatergic metabolism. Understanding these dysfunctional pathways could lead to new, possibly more successful therapeutic approaches to the management of migraine.
A Report of Cranial Autonomic Symptoms in Migraineurs
Authors: Gupta R , Bhatia MS
Published: November 2006

The presence of cranial autonomic symptoms in migraine is well known and thought to represent activation of the trigeminal parasympathetic reflex pathway similar to trigeminal autonomic cephalalgias. However, studies regarding the prevalence of these symptoms are few. The characteristics of migraineurs with cranial autonomic symptoms and the association of cranial autonomic symptoms with laterality of headache have never been studied in a clinic population. Seventy-eight consecutive subjects with migraine were recruited from the Headache Clinic of the Department of Psychiatry after exclusion of subjects with secondary headache. Their demographic data and detailed history of headache were noted and leading questions were asked regarding cranial autonomic symptoms. χ2 test and Fisher's exact test was used for categorical variables, whereas an independent sample t-test was applied on numerical data. Spearman's correlation was used for correlational analysis of categorical variables. Female subjects (78.2%) outnumbered males and the average duration of illness in the whole sample was 3.81 years. Migraine without aura (53.8%) was the commonest diagnosis, followed by migraine with aura (24.4%). Cranial autonomic symptoms were present in 73.1% of subjects and, commonly, they were ipsilateral to headache. Moreover, strictly unilateral cranial autonomic symptoms were reported by only 32% of patients. The anatomical side of headache did not affect the presence of autonomic symptoms. Those with or without autonomic symptoms did not differ with respect to gender, diagnosis, laterality of headache or associated symptoms except phonophobia, which was more common in subjects with autonomic symptoms ( P = 0.05). Those with autonomic symptoms had longer duration of illness ( P = 0.03) and longer headache episodes ( P = 0.04). In addition, sleep was ineffective in relieving their headache ( P = 0.02). Cranial autonomic symptoms are frequent in migraineurs and are common in subjects with long duration of illness and longer headache episodes. Clinical evidence in the present study suggests that subjects with cranial autonomic symptoms have a hyperactive efferent arm of trigeminal autonomic reflex. The connections of trigeminal nucleus with the locus coeruleus and dorsal raphe nucleus may account for the observed phenotypic differences between the two groups. Further research, however, is required to elucidate the underlying neural mechanisms of cranial autonomic symptoms in migraine.
Parental education, time in paid work and time with children: an Australian time‐diary analysis
Authors: Craig Lyn
Published: November 2006

How does parental education affect time in the paid workforce and time with children? Potentially, the effects are contradictory. An economic perspective suggests higher education means a pull to the market. Human capital theory predicts that, because higher education improves earning capacity, educated women face higher opportunity costs if they forego wages, so will allocate more time to market work and less to unpaid domestic labour. But education may also exercise a pull to the home. Attitudes to child rearing are subject to strong social norms, and parents with higher levels of education may be particularly receptive to the current social ideal of attentive, sustained and intensive nurturing. Using data from the Australian Bureau of Statistics Time‐use Survey 1997, this study offers a snapshot of how these contradictory pulls play out in daily life. It finds that in Australia, households with university‐educated parents spend more daily time with children than other households in physical care and in developmental activities. Sex inequality in care time persists, but fathers with university education do contribute more time to care of children, including time alone with them, than other fathers. Mothers with university education allocate more daily time than other mothers to both childcare and to paid work.
What's parenthood got to do with it?: men's hours of paid work1
Authors: Dermott Esther
Published: November 2006

It is commonly reported that fathers in Britain work longer hours than non‐fathers. This statistic is frequently used as supporting evidence for the argument that the role of fathers within families remains primarily concerned with financial provisioning. In this paper it is shown, through regression models, that once other factors are taken into account the significance of fatherhood in relation to hours of paid work disappears. This highlights fatherhood as a period in the life course which often coincides with longer working hours but challenges the assumption of a causal relationship.
Print and Public Politics in Seventeenth‐Century England
Authors: Peacey Jason
Published: November 2006

One of the most invigorating aspects of recent historiography regarding early modern political culture has been the determination, led by critics of ‘revisionism’, to revive interest in print culture. It is argued that printed texts reveal a less consensual world than revisionists suggest, that print was integral to public politics, and that pamphlets and newspapers ought to supplement, rather than be replaced by, manuscript sources. Ultimately, attempts to recover the vibrancy of political debate in early modern Britain have attracted scholars to the existence of ‘Grub Street’ practices within the world of polemic and news, and of a ‘public sphere’ of the kind outlined by Jurgen Habermas. This piece explores the validity of such concepts, and expresses caution about their applicability to the seventeenth century, while nevertheless suggesting alternative ways in which print culture may contribute to the post‐revisionist agenda.
Lessons from the Sustainability Movement: Toward An Integrative Decision-Making Framework for Nanotechnology
Authors: Meaney Mark E.
Published: November 2006

Like biotechnology before it, nanotechnology is beginning to provoke opposition from environmentalists concerned about the ethics of the development and application of nanotechnologies. Given the lack of data on environmental health and safety regarding how nanoparticles might impact the environment and effect the health of the human body, some environmentalists have called for limits on the production of nanoproducts until more research can be done to prove their safety. On the other side, while nanotech scientists and engineers agree that additional study of possible harmful effects is in order, they argue it would be unethical to turn our backs on what nanotechnology may do to help clean up the environment and improve health. They argue that a ban on nanomaterials would be shortsighted.
Nanotechnology: The Challenge of Regulating Known Unknowns
Authors: Wilson Robin Fretwell
Published: November 2006

Nanotechnology is a subject about which we know less than we should, but probably more than we think we do at first glance. Like Defense Secretary Donald Rumsfeld's “known unknowns,” we have learned enough to know what we should be concerned with. Glimmers of risk cropped up recently when German authorities recalled a bathroom cleansing product, “MagicNano,” that purported to contain nanosized particles (NSPs) and was on the market for only three days. More than one hundred people suffered severe respiratory problems – six of whom were hospitalized with pulmonary edema. Although a subsequent analysis of MagicNano found that the nanoliquid ingredient morphed in the production into “supersized” (not nanosized) particles, the recall nonetheless turned a white hot spotlight on the risk of NSPs. Latching onto the risks posed to workers producing materials using nanotechnology, the Washington Post has labeled nanotechnology a “seat-of-thepants occupational health experiment.”
The Social Conditions for Nanomedicine: Disruption, Systems, and Lock-In
Authors: Best Robert , Khushf George
Published: November 2006

Many believe that nanotechnology will be disruptive to our society. Presumably, this means that some people and even whole industries will be undermined by technological developments that nanoscience makes possible. This, in turn, implies that we should anticipate potential workforce disruptions, mitigate in advance social problems likely to arise, and work to fairly distribute the future benefits of nanotechnology. This general, somewhat vague sense of disruption, is very difficult to specify – what will it entail? And how can we responsibly anticipate and mitigate any problems? We can't even clearly state what the problems are anticipated to be. In fact, when we move from sweeping policy statements to more concrete accounts, nanotechnology seems to bifurcate into two divergent streams: one is fairly continuous with current developments, extending extant science in a quantitative way; the other is radically new, and includes science fiction-like dreams of molecular manufacturing and assemblers, with their utopian (or dystopian) scenarios of absolute plenty (or runaway self-replication). In these cases, “disruption” takes on the valence of Huxley's brave new world.