bluuebunny/crossref_metadata_2025 huggingface dataset:
Large‐scale prediction of disulphide bridges using kernel methods, two‐dimensional recursive neural networks, and weighted graph matching
Authors: Cheng Jianlin , Saigo Hiroto , Baldi Pierre
Published: December 2005

The formation of disulphide bridges between cysteines plays an important role in protein folding, structure, function, and evolution. Here, we develop new methods for predicting disulphide bridges in proteins. We first build a large curated data set of proteins containing disulphide bridges to extract relevant statistics. We then use kernel methods to predict whether a given protein chain contains intrachain disulphide bridges or not, and recursive neural networks to predict the bonding probabilities of each pair of cysteines in the chain. These probabilities in turn lead to an accurate estimation of the total number of disulphide bridges and to a weighted graph matching problem that can be addressed efficiently to infer the global disulphide bridge connectivity pattern. This approach can be applied both in situations where the bonded state of each cysteine is known, or in ab initio mode where the state is unknown. Furthermore, it can easily cope with chains containing an arbitrary number of disulphide bridges, overcoming one of the major limitations of previous approaches. It can classify individual cysteine residues as bonded or nonbonded with 87% specificity and 89% sensitivity. The estimate for the total number of bridges in each chain is correct 71% of the times, and within one from the true value over 94% of the times. The prediction of the overall disulphide connectivity pattern is exact in about 51% of the chains. In addition to using profiles in the input to leverage evolutionary information, including true (but not predicted) secondary structure and solvent accessibility information yields small but noticeable improvements. Finally, once the system is trained, predictions can be computed rapidly on a proteomic or protein‐engineering scale. The disulphide bridge prediction server (DIpro), software, and datasets are available through www.igb.uci.edu/servers/psss.html. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Multiphase structure of finite‐temperature phase diagram of the Blume–Capel model. Wang–Landau sampling method
Authors: Pawłowski G.
Published: December 2005

We investigate the density of states (DOS) in an antiferromagnetic spin‐system on a square lattice described by the Blume–Capel (BC) model. We use a new and very efficient simulation method, proposed by Wang and Landau, in which we estimate very precisely DOS by sampling in the space of energy. Then we calculate the thermodynamical averages like internal energy, free energy, specific heat and entropy.

The BC model exhibits multicritical behaviour such as first‐ or second‐order transitions and tricritical points. It is known that the ground state of the model can exhibit two kinds of staggered antiferromagnetic phases: AF1 (two interpenetrating lattices with S = –1 and S = 1) and AF2 (S = –1 and S = 0 for H < 0; S = 1 and S = 0 for H > 0). We analyze the coexistence of such phases at finite temperatures and determine border lines between them. To understand the microscopic nature of such boundaries we present also some results obtained with the standard Monte Carlo method. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Competition of ferromagnetism and superconductivity in Sc3InB
Authors: Wiendlocha B. , Tobola J. , Kaprzyk S. , Fruchart D. , Marcus J.
Published: December 2005

We present results of electronic structure calculations for the intermetallic perovskite Sc3InB with the full‐potential KKR‐LDA method. Sc3InB is a very promising candidate for a new superconductor (related to 8 K MgCNi3) and can be regarded as a boron‐inserted cubic Sc3In, which is a high‐pressure allotropic form of the hexagonal weak ferromagnet Sc3In. We predict that cubic Sc3In can also be magnetic, whereas Sc3InB having large DOS in the vicinity of E F exhibits non‐magnetic ground state. Estimation of the electron–phonon coupling for Sc3InB gives λ ≃ 1. Furthermore, the effect of vacancies in Sc3InB1–x and antisite disorder in Sc3(In‐B) on critical parameters is also discussed using the KKR–CPA method. All theoretical results support the possibility of the superconductivity onset in Sc3InB. Preliminary experimental measurements established the transition temperature close to 4.5 K, with a very abrupt change in susceptibility and a correlated drop of the resistivity when cooling. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of life cycle assessment to improve the environmental performance of a ceramic tile packaging system
Authors: Bovea M. D. , Serrano J. , Bruscas G. M. , Gallardo A.
Published: December 2005

The overall goal of this study was to evaluate the environmental performance of the process currently used to package and palletize ceramic floor and wall tiles, and to propose and analyse improvements from an environmental point of view. After developing a life cycle inventory of the primary and tertiary packaging, the life cycle assessment was applied according to mandatory and optional elements of ISO 14042. The results are presented in three parts: the first quantifies the environmental behaviour of the current packaging system, the second examines strategies focused on minimizing the environmental burdens of such critical elements, and the third quantifies the environmental improvements, compared with the initial situation, that are obtained with the application of each improvement. The simultaneous incorporation of all the proposed improvements into the packaging system can reduce impact within the 18–45% range, depending on the impact method that is applied. Copyright © 2005 John Wiley & Sons, Ltd.
Non‐centrosymmetric section forming shoulders in packaging machines
Authors: Zhou Yi‐Jie , Qian Xiao‐Ming
Published: December 2005

The mathematical description of a non‐centrosymmetric section, trapezoid shoulder is presented and the equations of the bending curve, the shoulder curved surface and the fringe curve are developed. Triangular, flat‐round, rectangular and round shoulders are discussed as special cases of the non‐centrosymmetric shoulder. To confirm the validity of the mathematical description, 3‐D shoulders are modelled on computer, and actual shoulders are manufactured by rapid manufacturing machine. Copyright © 2005 John Wiley & Sons, Ltd.
Perinatal outcome in monochorionic twin pregnancies complicated by amniotic fluid discordance without severe twin–twin transfusion syndrome
Authors: Huber A. , Diehl W. , Zikulnig L. , Bregenzer T. , Hackelöer B. J. , Hecher K.
Published: December 2005

Objectives

To assess the natural history and perinatal outcome in monochorionic diamniotic twin pregnancies with discordant amniotic fluid volume without signs of severe twin–twin transfusion syndrome (TTTS).

Methods

This was an observational study of 84 consecutive monochorionic twin pregnancies which did not meet the criteria for severe TTTS and endoscopic laser coagulation of placental anastomoses at initial presentation. The population was subdivided into two groups. Group 1 consisted of 64 pregnancies (median gestational age, 20.1 (range, 15.6–24.7) weeks) with amniotic fluid discordance and no signs of congestive heart failure in the twin with the larger amniotic fluid volume (Twin 1) and positive end‐diastolic flow in the umbilical artery of the twin with the smaller amniotic fluid volume (Twin 2). Group 2 (median gestational age, 19.1 (range, 16.0–24.4) weeks) consisted of 20 pregnancies with amniotic fluid discordance and intrauterine growth restriction (IUGR) (abdominal circumference < 5th percentile) in combination with absent or reversed end‐diastolic (ARED) flow in the umbilical artery of Twin 2. After exclusion of one patient from Group 1, who opted for termination of pregnancy, nine patients in Group 1 and one in Group 2 developed severe TTTS, and laser coagulation was offered. The remaining 54 pregnancies of Group 1 were compared with the remaining 19 pregnancies of Group 2.

Results

Fetuses in Group 1 showed significantly higher survival rates (overall survival, 100/108 (92.6%) vs. 23/38 (60%), P < 0.0001; survival of both fetuses, 49/54 (90.7%) vs. 9/19 (47.4%), P = 0.0002) and median gestational age at delivery (33.6, (range, 27.6–37.8) weeks vs. 32.0 (range, 26.9–36.3) weeks, P = 0.0457). Overall, there was a significantly higher incidence of complications, defined as necessity for intrauterine intervention, fetal or neonatal death or delivery prior to 32 weeks, in Group 2 (Group 1: 30/63 (47.6%); Group 2: 16/20 (80%), P = 0.0188).

Conclusions

Our data suggest that amniotic fluid discordance in monochorionic diamniotic twin pregnancies in combination with IUGR and umbilical artery ARED flow in one fetus represents an extremely high‐risk constellation for adverse pregnancy outcome. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Doppler and biophysical assessment in growth restricted fetuses: distribution of test results
Authors: Baschat A. A. , Galan H. L. , Bhide A. , Berg C. , Kush M. L. , Oepkes D. , Thilaganathan B. , Gembruch U. , Harman C. R.
Published: December 2005

Objective

Multi‐vessel Doppler ultrasonography and biophysical profile scoring (BPS) are used in the surveillance of growth restricted fetuses (IUGR). The interpretation of both tests performed concurrently may be complex. This study examines the relationship between Doppler ultrasonography and biophysical test results in IUGR fetuses.

Methods

Three hundred and twenty‐eight IUGR fetuses (abdominal circumference < 5th percentile, elevated umbilical artery (UA) pulsatility index (PI)) had concurrent surveillance with UA, middle cerebral artery (MCA) and ductus venosus (DV) Doppler ultrasonography and BPS (fetal tone, movement, breathing, maximal amniotic fluid pocket and fetal heart rate). Patients were stratified into three groups according to their Doppler examination: (1) abnormal UA alone; (2) brain sparing (MCA‐PI > 2 SD below mean for gestational age); and (3) abnormal DV (PI > 2 SD above the mean for gestational age) and BPS groups: (1) normal (> 6/10); (2) equivocal (6/10); and (3) abnormal (< 6/10). Predictions of short‐term perinatal outcomes by both modalities were compared for stratification. The distribution and concordance of Doppler and BPS test results were examined for the whole patient group and based on delivery prior to 32 weeks' gestation.

Results

Abnormal UA Doppler results alone were observed in 109 fetuses (33.2%), brain sparing in 87 (26.5%) and an abnormal DV in 132 (40.2%). The BPS was normal in 158 (48.2%), equivocal in 68 (20.7%) and abnormal in 102 (31.1%). Both testing modalities stratified patients into groups with comparable acid–base disturbance and perinatal outcome. Of the nine possible test combinations the largest subgroups were: abnormal UA alone/normal BPS (n = 69; 21%) and abnormal DV Doppler/abnormal BPS (n = 62; 18.9%). Assessment of compromise by both testing modalities was concordant in 146 (44.5%) cases. In 182 fetuses with discordant results the BPS grade was better in 115 (63.2%, P < 0.0001). Marked disagreement of test abnormality was present in 57 (17.4%) fetuses. Of these, abnormal venous Doppler in the presence of a normal BPS constituted the largest group (Chi‐square P < 0.002). Stratification was not significantly different in patients delivered prior to 32 weeks' gestation.

Conclusion

Doppler ultrasonography and BPS effectively stratify IUGR fetuses into risk categories, but Doppler and BPS results do not show a consistent relationship with each other. Since fetal deterioration appears to be independently reflected in these two testing modalities further research is warranted to investigate how they are best combined. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Experimental study of the effect of turbulence on horizontal axis wind turbine aerodynamics
Authors: Sicot Christophe , Devinant Philippe , Laverne Thomas , Loyer Stéphane , Hureau Jacques
Published: December 2005

Incident flows on wind turbines are often highly turbulent, because these devices operate in the atmospheric boundary layer and often in the wake of other wind turbines. This article presents experimental investigations of the effects of a high turbulence level on wind turbine aerodynamics. Power and thrust are measured on a horizontal axis wind turbine model in the ‘Lucien Malavard’ wind tunnel. A grid is used to generate three turbulence levels (4·4%, 9% and 12%) with integral length scale of the order of magnitude of the chord length. Experiments show little effect of turbulence on the wind turbine model power and thrust. This can be justified by analysis of the aerodynamic loads along the blade. Copyright © 2005 John Wiley & Sons, Ltd.
Serum digoxin concentration and outcomes in women with heart failure: A bi‐directional effect and a possible effect modification by ejection fraction
Authors: Ahmed Ali , Aban Inmaculada B. , Weaver Michael T. , Aronow Wilbert S. , Fleg Jerome L.
Published: December 2005

Background:

The association between serum digoxin concentration (SDC) and outcomes in women with heart failure (HF) has not been well studied.

Aims:

To test the hypothesis that the effect of digoxin on outcomes in women with HF is bi‐directional and dependent on SDC, as in men, and is modified by ejection fraction (EF).

Methods:

We studied 1366 female participants of the Digitalis Investigation Group trial in whom data on SDC (ng/ml) were available. We calculated adjusted odds ratios (AOR) and Bonferroni‐adjusted 97.5% confidence intervals (CI) for various outcomes at a median follow up of 41 months, in all women and stratified by EF 35%.

Results:

Compared with placebo (26.9%), 40.3% with SDC≥1.2 (AOR=1.80; CI=1.14–2.86; p=0.004) and 26.6% with SDC 0.5–1.1 (AOR=1.05; CI=0.73–1.51; p=0.762) died. Respective rates for HF‐hospitalizations were: placebo (32.8%), SDC≥1.2 (38.0%) and SDC 0.5–1.1 (25.5%). For women with EF<35% (N=677), SDC 0.5–1.1 lowered odds for HF‐hospitalizations (AOR=0.63; CI=0.39–1.00; p=0.026) without increasing odds for death (AOR=0.77; CI=0.47–1.26; p=0.233). In women with EF≥35% (N=689), SDC 0.5–1.1 had a borderline association with death (AOR=1.58; CI=0.92–2.72; p=0.058) but not with HF‐hospitalization (AOR=0.95; CI=0.54–1.66; p=0.826).

Conclusions:

As in men, in women with HF, digoxin has a bi‐directional effect based on SDC, and the beneficial effects were significant only among women with EF<35%.
NtPDR3, an iron‐deficiency inducible ABC transporter in Nicotiana tabacum
Authors: Ducos Eric , Fraysse Å Staffan , Boutry Marc
Published: November 2005

In plants, the ABC transporter PDR (pleiotropic drug resistance) subfamily is composed of approximately 15 genes, few of which have been analyzed. We have identified NtPDR3, a Nicotiana tabacum PDR gene belonging to a cluster for which no functional data was previously available. NtPDR3 was found to be induced in suspension cells treated with methyl jasmonate, salicylic acid, 1‐naphthalene acetic acid, or cembrene, a macrocyclic diterpene. In agreement with the identification of a putative iron deficiency element in the NtPDR3 transcription promoter region, we found that iron deficiency in the culture medium induced NtPDR3 expression, thus suggesting a new function of the PDR transporter family.
FORMULATING A FRAMEWORK FOR DIRECTORS’ DUTIES TO CREDITORS: AN ENTITY MAXIMISATION APPROACH
Authors: Keay Andrew
Published: November 2005

IT is now well settled in English law, as well as in several other common law jurisdictions, that when their company is in some form of financial difficulty, directors cannot ignore the interests of their companies’ creditors, but rather they have a duty to their company to consider those interests. This is all well and good, but while this general principle has been stated on many occasions by various courts, the courts have been slow to define important aspects of this responsibility. There are two major issues that have not been clarified. The first is this: from what point is the duty to consider creditor interests imposed on directors? There has been no unanimous judicial pronouncement on this issue, and this has produced some uncertainty. We know with some certainty that the duty does not operate where a company is clearly solvent. At the other extreme, we have certainty in that courts have said that the duty does apply where a company is insolvent.
ROGUES, SWINDLERS AND CHEATS: THE DEVELOPMENT OF MISTAKE OF IDENTITY IN ENGLISH CONTRACT LAW
Authors: MacMillan Catharine
Published: November 2005

THERE are few more vexed areas of contract law than that of a mistake as to the identity of a contracting party. The case law is difficult to reconcile. Judges and jurists disagree as to the effect of a mistake of identity upon the formation of a contract. This disagreement extends beyond discordance as to the operative principles to the very existence of the doctrine. That the issues are of current concern can be seen in the recent decision in Shogun Finance v. Hudson. This article examines how and why such a situation arose through an examination of the historical development of the doctrine. The thesis of this article is that the meaning of the early cases is obscured when they are viewed solely from a contractual perspective. The participants in these cases were also concerned with issues of criminal law and tort law. As these concerns disappeared from the law the meaning of the early cases was obscured and the cases have ceased to make sense. The article concludes with two sets of observations: first, what can be concluded, as a matter of legal history, from the development of this doctrine; secondly, how the modern law of mistake as to identity should regard these early cases.
Possibilities of near infrared reflectance spectroscopy for the prediction of organic carbon concentrations in grassland soils
Authors: VAN WAES C. , MESTDAGH I. , LOOTENS P. , CARLIER L.
Published: December 2005

For the determination of soil organic carbon (OC) concentrations, the availability of a fast, low-cost analysis method is required. The aim of the present study was to evaluate the possibilities of near infrared reflectance spectroscopy (NIRS) to build a spectral database and to develop calibrations for the prediction of organic carbon concentrations in grassland soils. NIRS spectra of 1626 soil samples from different grasslands (both agricultural and natural) were collected between 1100 and 2500 nm. NIRS calibrations were developed with modified partial least square regression and tested with independent validation samples. The best equations were obtained with the first derivative of the spectra without scatter corrections. For the global calibration, containing the samples of all origins, the standard errors of calibration (SEC) and of prediction (SEP) were respectively 3·70 g OC/kg dry soil (R2=0·89) and 3·95 g OC/kg dry soil (R2=0·88). The ratio of the standard deviation of the reference validation data to the SEP (RPD), indicating the performance of the calibration, was 2·9. Dividing the samples into groups according to their practice (agricultural or natural grassland), improved SEP by 5·8 and 7·7%, respectively. Dividing the samples into texture groups (clay, silt, sand) improved SEP for agricultural grassland by, on average, 7·4% and for natural grassland by 16·2%.
Profile of neurocognitive impairments associated with female in-patients with anorexia nervosa
Authors: FOWLER L. , BLACKWELL A. , JAFFA A. , PALMER R. , ROBBINS T. W. , SAHAKIAN B. J. , DOWSON J. H.
Published: December 2005

Background. Although many studies have reported impairments of neurocognitive performance in patients with anorexia nervosa (AN), these have involved a wide range of assessment methods and some findings are inconsistent.

Method. Twenty-five female in-patients with a DSM-IV diagnosis of AN, identified from three units specializing in the treatment of eating disorders, volunteered for the study. Twenty-five non-clinical control subjects were recruited, matched for age, gender and estimated IQ. Subjects were assessed with a range of computer-administered neurocognitive tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB), which has been validated in many studies of neuropsychiatric disorders.

Results. The patient group showed significant but moderate impairments (i.e. less than one standard deviation below the mean performance of the control group) on tests of spatial recognition memory, a planning task and rapid visual information processing, while a subgroup of patients (n=14) showed greater degrees of impairments on at least one of these tests. The degrees of impairments did not correlate with body mass index (BMI). No impairments were observed on tests of spatial span, pattern recognition memory, spatial working memory, matching-to-sample, paired associates learning and set-shifting.

Conclusions. The findings, in relation to a mean BMI of 15·3, are compatible with, in general, subtle impairments in neurocognition in AN. However, in those patients with relatively severe degrees of impairments, these may have adverse effects on complex tasks of social and occupational functioning. Further research is needed on the nature of relevant causal mechanisms, including the effects of potentially confounding variables.
Sherri Broder,Tramps, Unfit Mothers, and Neglected Children: Negotiating the Family in Nineteenth-Century Philadelphia. Philadelphia: University of Pennsylvania Press, 2002. 259 pp. $42.50 cloth.
Authors: Cantwell Christopher D.
Published: November 2005

With the relatively recent renovation of the American welfare system, the current dispute over faith-based organizations administering federal aid, and the wanton usage of the term family values in political discourse, few can deny that debate over the family, welfare, and the state remains heated. To add greater depth and nuance to this debate, Sherri Broder has delved into the complex relationships between the subjects and objects of social reform in late-nineteenth century Philadelphia. She explores how wealthy reformers, evangelical rescue workers, the labor movement, and laboring people “all drew on the discourse of the family”—which revolved around contested definitions of what constituted a tramp, unfit mother, or neglected child—“to define themselves variously as gendered members of different social classes, as respected family and community members, as political actors, and as people with claims on the state, the police, and public and private social services”(6). Utilizing local and national labor periodicals, the published works of charity organizations and individual reformers, and the institutional records of the Pennsylvania Society to Protect Children from Cruelty (SPCC) and the pseudonymous “Haven for Unwed Mothers and Infants,” Broder moves topically throughout five chapters dissecting different components of Philadelphia's discourse on the family.
Simulated worlds, physical eschatology, the finite nature hypothesis and the final anthropic principle
Authors: Prince N.H.E.
Published: December 2005

Meaning and purpose can be given to life, consciousness, the laws of physics, etc. If one assumes that the Universe is endowed with some form of (strong) anthropic principle. In particular, the final anthropic principle (FAP) of Barrow and Tipler postulates that intelligent life will continue in the Universe until the far future when the computational power of descendent civilizations will be sufficient to run simulations of enormous scale and power. Tipler has claimed that it will be possible to create simulations with rendered environments and inhabitants, i.e. intelligent software constructs, which are effectively ‘people’. Proponents of this FAP claim that if both substrate independence and the pattern identity postulate hold, then these simulations would be able to contain reanimated individuals that once lived. These claims have been heavily criticized but the growing study of physical eschatology, initiated by Freeman Dyson in a seminal work, and the developments in computational theory have made some progress in showing that simulations containing intelligent information processing software constructs, which may be conscious, are not only feasible but may be a reality within the next few centuries. In this work, arguments and conservative calculations are given which concur with these latter more minimal claims. FAP-type simulations inevitably rely on cosmology type, but current observations would seem to rule appropriate models out. However, it is argued that dark energy, described in the recent forms of ‘quintessence’ cosmological models may show the current conclusions from observations to be too presumptive. In this paper some relevant physical and cosmological aspects are reviewed in the light of the recent propositions regarding the plausibility of certain simulations given by Bostrom, and the longer held postulate of finite nature – due to Fredkin – which has grown in credibility, following advances in quantum mechanics and the computational theory of cellular automata. This latter postulate supports the conclusions of Bostrom, which, under certain plausible assumptions, can imply that our Universe is itself already a simulated entity. It is demonstrated in this paper how atemporal memory connections could make efficient ancestor simulations possible, solving many of the objections faced by the FAP of Barrow and Tipler. Also, if finite nature is true then it can offer a similar vindication to this FAP. Indeed the conclusions of this postulate can be realized more easily, but only if the existence of life within the simulation/Universe is not merely incidental to the (currently unknown) purpose for which it was generated to fulfil.
Early events of peripheral nerve regeneration
Authors: MCDONALD DAVID , CHENG CHU , CHEN YUANYUAN , ZOCHODNE DOUGLAS
Published: December 2005

Early regeneration of injured peripheral nerves involves a series of events that are important in the success of eventual reconnection. In many nerve injuries, such as transections with gaps, axons and Schwann cells (SCs) penetrate into new microenvironments de novo, not involving zones of Wallerian degeneration. We studied unexplored axon–SC interactions by sampling of newly forming connections through a silicone conduit across transected rat sciatic peripheral nerve gaps. Axon and SC participation in bridge formation was addressed by light microscopy, electron microscopy and by double-labeling immunohistochemistry, including confocal imaging, and several, less appreciated aspects of early regrowth were identified. There are limitations to early and widespread regeneration of axons and SCs into bridges initially formed from connective tissue and blood vessels. Regrowth is ‘staggered’ such that only a small percentage of parent axons sampled the early bridge. There is an intimate, almost invariable relationship between SCs and extension of axons, which challenges the concept that axons lead and SCs follow. ‘Naked’ axons were infrequent and limited in scope. Axons did not seek out and adhere to vascular laminin but intimately followed laminin deposits associated with apposed SCs. Growth cones identified by labeling of β III tubulin, PGP 9.5 and GAP43/B50 were complex, implying a pause in their regrowth, and were most prominent at the proximal stump–regenerative bridge interface. There is surprising and substantial hostility to local regrowth of axons into newly forming peripheral nerve bridges. Early axon outgrowth, associated with apposed Schwann cell processes, is highly constrained even when not exposed to adjacent myelin and products of Wallerian degeneration.
Integral cross sections for the direct excitation of the A 3Σu+, B 3Πg, W 3Δu, B′ 3Σu−, a′ 1Σu−, a 1Πg, w 1Δu, and C 3Πu electronic states in N2 by electron impact
Authors: Johnson P. V. , Malone C. P. , Kanik I. , Tran K. , Khakoo M. A.
Published: November 2005

Integral cross sections for electron impact excitation out of the ground state (X 1Σg+) to the A 3Σu+, B 3Πg, W 3Δu, B′ 3Σu−, a′ 1Σu−, a 1Πg, w 1Δu, and C 3Πu states in N2 are reported at incident energies ranging between 10 and 100 eV. These data have been derived by integrating differential cross sections previously reported by this group. New differential cross section measurements for the a 1Πg state at 200 eV are also presented to extend the range of the reported integral cross sections for this state, which is responsible for the emissions of the Lyman‐Birge‐Hopfield band system (a 1Πg → X 1Σg+). The present results are compared and critically evaluated against existing cross sections. In general, the present cross sections are smaller than previous results at low impact energies from threshold through the excitation function peak regions. These lower cross sections have potentially significant implications on our understanding of UV emissions in the atmospheres of Earth and Titan.
Complex geology of two large impact craters in Tyrrhena Terra, Mars: Detailed analysis using MEX HRSC camera data
Authors: Korteniemi J. , Kostama V.‐P. , Törmänen T. , Aittola M. , Öhman T. , Lahtela H. , Raitala J. , Neukum G.
Published: November 2005

Tyrrhena Terra, located just north of the roughly 200 km Hellas impact basin, is a typical region of the ancient cratered southern highlands on Mars. Its base material is a mixture of Hellas ejecta, prebasin remnants, and highland terrain, all later saturated with smaller (<200 km) impact craters. Fluvial and lacustrine deposits, erosion, tectonic movements, volcanic materials and aeolian processes have subsequently modified the region further. In this study we take a closer look at two adjacent unnamed craters in Tyrrhena Terra, located at 24.5°S, 80.8°E (crater “A”) and 23.9°S, 79.3°E (crater “B”). The craters are covered by the ∼20–80 m/pixel Mars Express High Resolution Stereo Color imager (HRSC) multispectral data, which together with MOC, THEMIS, and MOLA data sets allows us to make very detailed analysis of the area. We describe several identified geological and geomorphological units with their individual characteristics (e.g., morphology, color, cratering records, and elevation differences) and interpret their individual evolution. The crater floors show several unique material types of both depositional and erosional origin. Crater A has a large 200 m high central massif and a central peak ring as well as a unique low‐lying terrain type, “honeycomb terrain,” with narrow 50–200 m high ridges and intervening pits. Additionally, both craters exhibit erosional features similar to each other and nearby craters, indicating episodes of deposition of various material types in both craters. We find that the crater pair reveals many characteristics which are typical of the N Hellas rim but are not found elsewhere.
An EELS‐based study of the effects of pyrolysis on natural carbonaceous materials used for activated charcoal preparation
Authors: Jeanne‐Rose V. , Golabkan V. , Mansot J. L. , Largitte L. , Césaire T. , Ouensanga A.
Published: December 2005

Electron energy‐loss spectroscopy (EELS) has been used to characterize the electronic structure of charcoal phases at the nanoscale, thus demonstrating that the technique can be applied to environmental science. Activated charcoal is extensively used to remove pollutants from liquid and gaseous sewage. It is mainly obtained by activation of coke or charcoal produced from ligneous precursors. The present study concerns the use of by‐products of local Caribbean agriculture, such as sugar cane bagasse, fruit stones and seeds, for use as activated charcoal precursors. Charcoal phases are prepared by high‐temperature pyrolysis of lignocellulosic raw materials under a nitrogen gas flow. With the aim of optimizing the pyrolysis temperature and duration and oxygen content, the concentration of carbon sp2 hybridized chemical bonds and structural ordering have been followed by EELS for different treatment temperatures. To quantify the carbon sp2 content, near edge structure (NES) at the carbon K edge has been measured to determine the strength of π → π* and 1s → π* transitions. Three precursors of plant origin, shells of Terminalia catappa and Acrocomia karukerana and seeds of Psidium guajava, with the pyrolysis temperatures between 600 and 900 °C, were investigated. The fraction of carbon sp2 bonding is found to increase when the temperature rises from 600 °C to the range 700–750 °C and becomes stable at higher temperatures. For temperatures in excess of 700 °C, structural ordering probably occurs and well‐defined 1s → σ* NES is present, whose intensity increases with increasing preparation temperature. For the highest temperature of around 900 °C, the structure of the final product is less well organized than graphitized carbon but a few per cent of a highly ordered phase is found.
Intracellular calcium modulates the nuclear translocation of calsenilin
Authors: Zaidi Nikhat F. , Thomson Emma E. , Choi Eun‐Kyoung , Buxbaum Joseph D. , Wasco Wilma
Published: December 2005

Calsenilin, which was originally identified as a presenilin interacting protein, has since been shown to be involved in the processing of presenilin(s), the modulation of amyloid β‐peptide (Aβ) levels and apoptosis. Subsequent to its original identification, calsenilin was shown to act as a downstream regulatory element antagonist modulator (and termed DREAM), as well as to interact with and modulate A‐type potassium channels (and termed KChIP3). Calsenilin is primarily a cytoplasmic protein that must translocate to the nucleus to perform its function as a transcriptional repressor. This study was designed to determine the cellular events that modulate the translocation of calsenilin from the cytoplasm to the nucleus. The nuclear translocation of calsenilin was found to be enhanced following serum deprivation. A similar effect was observed when cells were treated with pharmacological agents that directly manipulate the levels of intracellular calcium (caffeine and the calcium ionophore A23187), suggesting that the increased levels of calsenilin in the nucleus are mediated by changes in intracellular calcium. A calsenilin mutant that was incapable of binding calcium retained the ability to translocate to the nucleus. Taken together, these findings indicate that the level of intracellular calcium can modulate the nuclear translocation of calsenilin and that this process does not involve the direct binding of calcium to calsenilin.
Induction of motor neuron apoptosis by free 3‐nitro‐l‐tyrosine
Authors: Peluffo Hugo , Shacka John J. , Ricart Karina , Bisig C. Gaston , Martìnez‐Palma Laura , Pritsch Otto , Kamaid Andrès , Eiserich Jason P. , Crow John P. , Barbeito Luis , Estèvez Alvaro G.
Published: December 2005

Peroxynitrite‐dependent tyrosine nitration has been postulated to be involved in motor neuron degeneration in amyotrophic lateral sclerosis (ALS). Evidence supporting this supposition includes the appearance of both free and protein‐linked 3‐nitro‐l‐tyrosine (nitrotyrosine) in both sporadic and familial ALS, as well as of increased free nitrotyrosine levels in the spinal cord of transgenic mice expressing ALS‐linked superoxide dismutase mutants at symptom onset. Here we demonstrate that incubation with clinically relevant concentrations of nitrotyrosine induced apoptosis in motor neurons cultured with trophic factors. Nitrotyrosine was bound to proteins, but it was not incorporated into α‐tubulin, as previously demonstrated for other cell types. Neither inhibition of nitric oxide production nor scavenging of superoxide and peroxynitrite prevented increases in cell nitrotyrosine immunoreactivity or motor neuron death, suggesting that these effects are not due to the endogenous formation of reactive nitrogen species. In contrast, some populations of astrocytes incorporated nitrotyrosine into α‐tubulin, but free nitrotyrosine had no effect on the viability and phenotype of astrocytes in culture, as evaluated by glial fibrillary acidic protein immunoreactivity, cell growth and morphology. Co‐culture of motor neurons on astrocyte monolayers delayed, but did not prevent, nitrotyrosine‐induced motor neuron death. These results suggest that free nitrotyrosine may play a role in the induction of motor neuron apoptosis in ALS.
AnAufbau Ansatzfor geminal functional theory
Authors: Rinderspacher B. Christopher , Schreiner Peter R.
Published: December 2005

We generalize antisymmetric geminal products to more than just one generating geminal using an Aufbau Ansatz similar to the Hartree-Fock theory. Investigation of Li−, Be, B+, LiH, BeH+, and He2 shows a very high recovery of electron-correlation energy using this Aufbau Ansatz. The method is inherently multideterminantal and insensitive to symmetry problems. The computational complexity is en par with configuration interaction of singles and doubles.
Collisional deactivation mechanism of luminescence in hydrogen-loaded Ge-doped fibers
Authors: Médjahdi K. , Boukenter A. , Ouerdane Y.
Published: December 2005

We report experimental results on the temperature and Ge-content dependencies of the decay times of the 3.1eV emission of twofold-coordinated germaniums, excited at 3.51eV, in both virgin and H2-loaded germanosilicate optical fibers. For T<110K, the lifetimes are temperature invariant in the two kinds of fibers; at higher temperatures, they are progressively shortened in the H2-loaded fibers whereas they remain unaltered in the virgin fibers. On increasing the Ge content in the fiber core the lifetime decreases in the whole temperature range. We also found a direct correlation in H2-loaded samples between the dependencies on temperature of the emission lifetime and the diffusion lengths of H2 molecules in silica glass determined from earlier work. These experimental features are explained by assuming an elastic-collisional deactivation mechanism due to interaction with diffusing H2 molecules, described in terms of an Arrhenius law with activation energy ∼64meV that operates in competition with the normal radiative process.
Kinetic theory of nucleation based on a first passage time analysis: Improvement by the density-functional theory
Authors: Djikaev Y. S. , Ruckenstein E.
Published: December 2005

A recent kinetic theory of nucleation [see, e.g., E. Ruckenstein and B. Nowakowski, J. Colloid Interface Sci. 137, 583 (1990)] is based on molecular interactions and avoids the traditional thermodynamics. The rate of emission of molecules from a cluster is found via a first passage time analysis. This time is calculated by solving the single-molecule master equation for the probability distribution function of a surface molecule located in the potential field created by the cluster. The liquid cluster was assumed to have sharp boundaries and uniform density. In the present paper, this assumption is removed by using the density-functional theory to find the density profiles. Thus, more accurate calculations of the potential field created by the cluster, its emission rate, and nucleation rate are obtained. The modified theory is illustrated by numerical calculations for a molecular pair interaction potential combining the dispersive attraction with the hard-sphere repulsion.
Powerful terahertz emission from laser wake fields excited in inhomogeneous plasmas
Authors: Sheng Zheng-Ming , Mima Kunioki , Zhang Jie
Published: December 2005

Powerful coherent emission of broadband few-terahertz radiation can be produced from a laser wake field by linear mode conversion. This occurs when the laser pulse is incident obliquely to the density gradient of inhomogeneous plasmas. The emission spectrum and conversion efficiency predicted by mode conversion theory are in agreement with particle-in-cell simulations. The energy conversion efficiency from laser pulses to this low-frequency emission scales proportional to their frequency ratio by (ω∕ω0)3 and increases with the laser intensity and the plasma density scale length. By adjusting the laser pulse duration and plasma density profiles, one can control the emission frequency, bandwidth, and duration. In two- and three-dimensional geometry, conical wake emission is found in the backward direction when the laser pulse propagates along the density gradient. This can be explained well by the linear mode conversion. To avoid conical emission, a laser pulse incident obliquely to the density gradient can be deployed so that collimated emission becomes dominant in the “specular reflection” direction, suitable for practical applications.
Optical properties of self-organized wurtzite InN∕GaN quantum dots: A combined atomistic tight-binding and full configuration interaction calculation
Authors: Baer N. , Schulz S. , Schumacher S. , Gartner P. , Czycholl G. , Jahnke F.
Published: November 2005

In this work, we investigate the electronic and optical properties of self-assembled InN∕GaN quantum dots. The one-particle states of the low-dimensional heterostructures are provided by a tight-binding model that fully includes the wurtzite crystal structure on an atomistic level. Optical dipole and Coulomb matrix elements are calculated from these one-particle wave functions and serve as an input for full configuration interaction calculations. We present multiexciton emission spectra and discuss in detail how Coulomb correlations and oscillator strengths are changed by the piezoelectric fields present in the structure. Vanishing exciton and biexciton ground state emission for small lens-shaped dots is predicted.
Spectral transfers and zonal flow dynamics in the generalized Charney-Hasegawa-Mima model
Authors: Lashmore-Davies C. N. , Thyagaraja A. , McCarthy D. R.
Published: December 2005

The mechanism of four nonlinearly interacting drift or Rossby waves is used as the basic process underlying the turbulent evolution of both the Charney-Hasegawa-Mima-equation (CHME) and its generalized modification (GCHME). Hasegawa and Kodama’s concept of equivalent action (or quanta) is applied to the four-wave system and shown to control the distribution of energy and enstrophy between the modes. A numerical study of the GCHME is described in which the initial state contains a single finite-amplitude drift wave (the pump wave), and all the modulationally unstable modes are present at the same low level (10−6 times the pump amplitude). The simulation shows that at first the fastest-growing modulationally unstable modes dominate but reveals that at a later time, before pump depletion occurs, long- and short-wavelength modes, driven by pairs of fast-growing modes, grow at 2γmax. The numerical simulation illustrates the development of a spectrum of turbulent modes from a finite-amplitude pump wave.
Effect of ion beam energy and polymer weight on the thickness of nanowires produced by ion bombardment of polystyrene thin films
Authors: Tsukuda Satoshi , Seki Shu , Tagawa Seiichi , Sugimoto Masaki
Published: December 2005

Exposure of polystyrene to MeV-order heavy-ion beams produces nanowires by cross-linking along ion tracks. The chemical core of these ion tracks is visualized, and the dependence of the diameter of the nanowires on the linear energy transfer of the ion beam and molecular weight of the polymer are investigated precisely based on the model of transformation of a nanowire cross section into an ellipse. an equation is derived to predict the radius (5.6–27.6 nm) of the chemical core considering the energy density required for gelation of the polymer, and the validity of the relation is confirmed against experimental results.
Organic solar cells with sensitivity extending into the near infrared
Authors: Rand Barry P. , Xue Jiangeng , Yang Fan , Forrest Stephen R.
Published: December 2005

We describe an organic photovoltaic cell based on a tin(II) phthalocyanine (SnPc)∕C60 donor/acceptor heterojunction with sensitivity at wavelengths of λ>900nm. We find that the low hole mobility in polycrystalline thin films of SnPc, μh=(2±1)×10−10cm2∕Vs, prevents the use of thick layers, leading to low fill factors and therefore low-power conversion efficiencies. However, owing to its large absorption coefficient, a 50-Å-thick layer of SnPC yields solar cell external quantum efficiencies of up to 21% at λ=750nm. With the double heterostructure of indium-tin oxide/100Å copper phthalocyanine/50Å SnPc∕540Å C60∕75Å bathocuproine/Ag, we obtain a power conversion efficiency of (1.0±0.1)% under 1 sun standard AM1.5G solar illumination and efficiencies of (1.3±0.1)% under intense (10 suns) standard AM1.5G solar illumination.
Adverse pressure gradient effect on nonlinear varicose instability of a streaky structure in an unswept wing boundary layer
Authors: Litvinenko Yu. A. , Chernoray V. G. , Kozlov V. V. , Grek G. R. , Löfdahl L. , Chun Ho Hwan
Published: November 2005

Nonlinear varicose instability of a streaky structure is experimentally investigated in a wing boundary layer. Spatial evolution of the streaky structure perturbed by high-frequency traveling waves is compared at zero and adverse streamwise pressure gradients. The process of streak multiplication and generation of Λ-shaped vortices is under examination. Results obtained testify to the strong influence of pressure gradient upon the breakdown of the streaky structure due to its varicose instability.
Analytical modeling of particle stopping distance at low pressure to evaluate protection schemes for extreme ultraviolet lithography masks
Authors: Asbach Christof , Kim Jung Hyeun , Yook Se-Jin , Pui David Y. H. , Fissan Heinz
Published: December 2005

We developed an analytical model that predicts the distance, particles can travel towards the critical surface of an extreme ultraviolet lithography mask as a function of their initial velocity and all forces (gravity, drag, thermophoresis, and electrophoresis) acting on the particles. To avoid gravitational settling of particles onto the mask, its critical surface is facing down. The model shows that at the low pressure level (50 mTorr), drag force is the dominating force to decelerate particles. Thermophoresis can add additional protection. Electrophoresis can be very effective, however, all particles must be unipolarly charged to make use of the Coulomb force.
Symbiosis of Acacia auriculiformis and Acacia mangium with mycorrhizal fungi and Bradyrhizobium spp. improves salt tolerance in greenhouse conditions
Authors: Diouf Diégane , Duponnois Robin , Tidiane Ba Amadou , Neyra Marc , Lesueur Didier
Published: December 2005

The aim of our work was to assess the growth and mineral nutrition of salt stressed Acacia auriculiformis A. Cunn. ex Benth. and Acacia mangium Willd. seedlings inoculated with a combination of selected microsymbionts (bradyrhizobia and mycorrhizal fungi). Plants were grown in greenhouse conditions in non-sterile soil, irrigated with a saline nutrient solution (0, 50 and 100 mm NaCl). The inoculation combinations consisted of the Bradyrhizobium strain Aust 13c for A. mangium and Aust 11c for A. auriculiformis, an arbuscular mycorrhizal fungus (Glomus intraradices, DAOM 181602) and an ectomycorrhizal fungus (Pisolithus albus, strain COI 007). The inoculation treatments were designed to identify the symbionts that might improve the salt tolerance of both Acacia species. The main effect of salinity was reduced tree growth in both acacias. However, it appeared that, compared with controls, both rhizobial and mycorrhizal inoculation improved the growth of the salt-stressed plants, while inoculation with the ectomycorrhizal fungus strain appeared to have a small effect on their growth and mineral nutrition levels. Endomycorrhizal inoculation combined with rhizobial inoculation usually gave good results. Analysis of foliar proline accumulation confirmed that dual inoculation gave the trees better tolerance to salt stress and suggested that the use of this dual inoculum might be beneficial for inoculation of both Acacia species in soils with moderate salt constraints.