bluuebunny/crossref_metadata_2025 huggingface dataset:
C‐C chemokine receptor 2 (CCR2) deficiency improves bleomycin‐induced pulmonary fibrosis by attenuation of both macrophage infiltration and production of macrophage‐derived matrix metalloproteinases
Authors: Okuma Toshiyuki , Terasaki Yasuhiro , Kaikita Koichi , Kobayashi Hironori , Kuziel William A , Kawasuji Michio , Takeya Motohiro
Published: November 2004

Macrophage infiltration is implicated in various types of pulmonary fibrosis. One important pathogenetic process associated with pulmonary fibrosis is injury to basement membranes by matrix metalloproteinases (MMPs) that are produced mainly by macrophages. In this study, C‐C chemokine receptor 2‐deficient (CCR2−/−) mice were used to explore the relationship between macrophage infiltration and MMP activity in the pathogenesis of pulmonary fibrosis, using the bleomycin‐induced model of this disease process. CCR2 is the main (if not only) receptor for monocyte chemoattractant protein‐1/C‐C chemokine ligand 2 (MCP‐1/CCL2), which is a critical mediator of macrophage trafficking, and CCR2 −/− mice demonstrate defective macrophage migration. Pulmonary fibrosis was induced in CCR2−/− and wild‐type (CCR2+/+) mice by intratracheal instillation of bleomycin. No significant differences in the total protein concentration in bronchoalveolar lavage (BAL) fluid, or in the degree of histological lung inflammation, were observed in the two groups until day 7. Between days 3 and 21, however, BAL fluid from CCR2−/− mice contained fewer macrophages than BAL fluid from CCR2+/+ mice. Gelatin zymography of BAL fluid and in situ zymography revealed reduced gelatinolytic activity in CCR2−/− mice. Immunocytochemical staining showed weaker expression of MMP‐2 and MMP‐9 in macrophages in BAL fluid from CCR2−/− mice at day 3. Gelatin zymography of protein extracted from alveolar macrophages showed reduced gelatinolytic activity of MMP‐2 and MMP‐9 in CCR2−/− mice. At days 14 and 21, lung remodelling and the hydroxyproline content of lung tissues were significantly reduced in CCR2−/− mice. These results suggest that the CCL2/CCR2 functional pathway is involved in the pathogenesis of bleomycin‐induced pulmonary fibrosis and that CCR2 deficiency may improve the outcome of this disease by regulating macrophage infiltration and macrophage‐derived MMP‐2 and MMP‐9 production. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Renal ACE2 expression in human kidney disease
Authors: Lely AT , Hamming I , van Goor H , Navis GJ
Published: November 2004

Angiotensin‐converting enzyme 2 (ACE2) is a recently discovered homologue of angiotensin‐converting enzyme (ACE) that is thought to counterbalance ACE. ACE2 cleaves angiotensin I and angiotensin II into the inactive angiotensin 1–9, and the vasodilator and anti‐proliferative angiotensin 1–7, respectively. ACE2 is known to be present in human kidney, but no data on renal disease are available to date. Renal biopsies from 58 patients with diverse primary and secondary renal diseases were studied (hypertensive nephropathy n = 5, IgA glomerulopathy n = 8, minimal change nephropathy n = 7, diabetic nephropathy n = 8, focal glomerulosclerosis n = 5, vasculitis n = 7, and membranous glomerulopathy n = 18) in addition to 17 renal transplants and 18 samples from normal renal tissue. Immunohistochemical staining for ACE2 was scored semi‐quantitatively. In control kidneys, ACE2 was present in tubular and glomerular epithelium and in vascular smooth muscle cells and the endothelium of interlobular arteries. In all primary and secondary renal diseases, and renal transplants, neo‐expression of ACE2 was found in glomerular and peritubular capillary endothelium. There were no differences between the various renal disorders, or between acute and chronic rejection and control transplants. ACE inhibitor treatment did not alter ACE2 expression. In primary and secondary renal disease, and in transplanted kidneys, neo‐expression of ACE2 occurs in glomerular and peritubular capillary endothelium. Further studies should elucidate the possible protective mechanisms involved in the de novo expression of ACE2 in renal disease. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Rate enhancement for nitroxide stable free radical polymerization of n‐butyl acrylate by dodecylbenzenesulfonic acid
Authors: Cheng Kuo‐Chung , Chen Jiun‐Jeng , Chiu Wen‐Yen , Wang Lee Yih , Wang Ping‐Chieh
Published: November 2004

Dodecylbenzenesulfonic acid, DDBSA, was chosen as a new rate‐accelerating additive for 2,2,6,6,‐teramethyl‐1‐piperidinyloxy (TEMPO)‐mediated stable free radical polymerization of n‐butyl acrylate (n‐BA) monomers with 2,2′‐azobisisobutyronitrile (AIBN). It was found that the number‐average molecular weight of polymers could reach about ten thousand with a narrow polydispersity index (PDI) of 1.4 in a few minutes, which was faster than other systems reported previously. But, at higher conversion, the molecular weight distribution of polymers became broad, and a bimodal distribution occurred. The macro‐initiators isolated from the former polymers with narrow PDI could be extended by polymerization with monomers by the addition of DDBSA. Furthermore, a proposed kinetic model demonstrated that the decay of the concentration of DDBSA would reduce the living polymer concentration and retard the growth of the polymers, which could be further propagated by the supplement of DDBSA. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 42–49, 2005
Biological–synthetic hybrid block copolymers: Combining the best from two worlds
Authors: Klok Harm‐Anton
Published: November 2004

Although biopolymers and synthetic polymers share many common features, each of these two classes of materials is also characterized by a distinct and very specific set of advantages and disadvantages. Combining biopolymer elements with synthetic polymers into a single macromolecular conjugate is an interesting strategy for synergetically merging the properties of the individual components and overcoming some of their limitations. This article focuses on a special class of biological–synthetic hybrids that are obtained by site‐selective conjugation of a protein or peptide and a synthetic polymer. The first part of the article gives an overview of the different liquid‐phase and solid‐phase techniques that have been developed for the synthesis of well‐defined, that is, site‐selectively conjugated, synthetic polymer–protein hybrids. In the second part, the properties and potential applications of these materials are discussed. The conjugation of biological and synthetic macromolecules allows the modulation of protein binding and recognition properties and is a powerful strategy for mediating the self‐assembly of synthetic polymers. Synthetic polymer–protein hybrids are already used as medicines and show significant promise for bioanalytical applications and bioseparations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1–17, 2005
Device model for poly(o‐methoxyaniline) field‐effect transistor
Authors: Bianchi R. F. , Onmori R. K. , Faria R. M.
Published: November 2004

We present a detailed study of the electric mechanism of a thin poly(o‐methoxyaniline) (POMA) field‐effect transistor. The device was prepared using Al‐Si/SiO2/(interdigitated gold lines array)/POMA structure as the gate electrode, insulating layer, source‐drain electrodes, and active layer, respectively. A model is presented for the electrical characteristics of such a device that encompasses the disordered properties of the POMA, the source‐drain electrical‐field dependence of hole mobility, and the carrier and mobility gradients in directions perpendicular to the polymer–oxide interface. The fittings of source‐drain current versus source‐drain voltage, having as parameters the gate voltage, is in good agreement with the experimental data, and the dependence of both the carrier saturation velocity and of the carrier mobility with the gate voltage are obtained. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 74–78, 2005
Preferential humoral immune response in prostate cancer to cellular proteins p90 and p62 in a panel of tumor‐associated antigens
Authors: Shi Fu‐Dong , Zhang Jian‐Ying , Liu Daorong , Rearden Ann , Elliot Max , Nachtsheim Dan , Daniels Tracy , Casiano Carlos A. , Heeb Mary Jo , Chan Edward K.L. , Tan Eng M.
Published: November 2004

BACKGROUND

Cytoplasmic p90 autoantigen was recently cloned from a cDNA expression library using serum antibody from a cancer patient. The humoral immune response to p90 in prostate cancer and benign prostatic hyperplasia (BPH) was examined.

METHODS

An antigenic fragment of recombinant p90 protein and several other tumor‐associated antigens (TAAs) were used in ELISA and Western blotting to detect antibodies in sera from patients with prostate cancer, BPH, and other controls.

RESULTS

Autoantibodies to p90 were detected in 30.8% of 133 prostate cancer patients versus 1.5% in 68 BPH patients. When a selected panel of six TAAs including p90 were used for immunoscreening, the cumulative positive reactions in prostate cancer sera reached 92.5%, significantly higher than in BPH and other control sera. Antibodies to p90 showed the highest frequency in prostate cancer (30.8%), followed by antibodies to p62 (22.6%).

CONCLUSIONS

A panel of six selected TAAs was shown to have high sensitivity and specificity as immunodiagnostic markers in prostate cancer. © 2004 Wiley‐Liss, Inc.
Removal of sodium and potassium adducts using a matrix additive during matrix‐associated laser desorption/ionization time‐of‐flight mass spectrometric analysis of peptides
Authors: Leite John F. , Hajivandi Mahbod R. , Diller Thomas , Pope R. Marshall
Published: November 2004

Monovalent cations often associate with peptides and proteins under mass spectrometry (MS) conditions, resulting in a discernable, but often misleading, adduct cluster pattern. These adduct cluster peaks reduce the signal intensity of specific peptide species by splitting the ion population into multiple mass peaks, suppressing the ionization of neighboring low‐abundance peaks, and interfering with identification of post‐translational modifications. Further, monovalent contaminants tend to form a distribution of matrix cluster peaks in matrix‐associated laser desorption/ionization time‐of‐flight (MALDI‐TOF) spectra causing interference and suppression in the mass range below 1400 Da. The most common method for reduction or elimination of adduct clusters is solid‐phase extraction via a pipette tip or spin column, which often leads to loss of low‐abundance peptide components. In this study we describe the use of a commercially available surfactant blend that markedly reduces the adduction of monovalent cations during peptide analysis by MALDI‐TOFMS. Copyright © 2004 John Wiley & Sons, Ltd.
An adenovirus vector encoding tyrosine hydroxylase activity may enter human CNS cells in primary dissociated cultures
Authors: Levallois Christine , Mallet Jacques , Privat Alain
Published: November 2004

An adenovirus encoding tyrosine hydroxylase (TH) activity was inserted in neuronal and glial cultured cells obtained from human fetal central nervous system (CNS) tissue. Using a double fluorescence immunostaining, we characterized inoculated CNS cells, with a TH antiserum and one of the following antibodies: microtubule‐associated protein (MAP2) and GABA for neuronal cells, vimentin (Vim) for glial cells and glial fibrillary acidic protein (GFAP) for astrocytes. The characterization of inoculated neuronal cells was established by the detection of TH‐MAP2‐stained neurons in cultures obtained from the thoracic and lumbar parts of the spinal cord where no intrinsic TH cells are described. Inoculated glial cells were characterized by the detection of TH‐Vim and TH‐GFAP‐stained CNS cultured cells. We also observed GABA neurons expressing TH immunoreactivity which could be considered as inoculated neurons expressing the GABA phenotype. Whatever the time of inoculation, transfection was observed in both neuronal and glial cells, after up to 4 months of culture. Although no precise quantitation was performed, the percentage of inoculation was found on microscopic inspection to be greater in glia than in neurons, as previously reported. We concluded that a gene coding for a key neuronal enzyme can be incorporated in embryonic human glial and neuronal cells through the use of a recombinant adenovirus.
Differential expression of the soluble 170 kDa brain protein in the fetal and adult human brain
Authors: Yew D.T. , Webb S.E. , Wong C.K. , Hui K.‐S.
Published: November 2004

The expression of the soluble 170 kDa brain protein (BP170) was studied in the developing human brain. Using immunohistochemical methods, it was possible to demonstrate that BP170 was expressed very strongly in the visual cortex up to approximately 27 weeks of gestation. After this time, the level of expression was reduced so that by adulthood the levels of BPI 70 were negligible. Similarly, BP170 was expressed in the hippocampus at all stages of development; however, unlike in the visual cortex, this protein was still apparent, albeit at low levels, in the adult. In addition, BP170 was co‐expressed with tyrosine hydroxylase which suggests its possible role in the dopamine pathway.
Early stages of development in Usnea antarctica Du Rietz in the South Shetland Islands, northern maritime Antarctica
Authors: OTT Sieglinde
Published: November 2004

Juvenile development has been investigated for the first time in an Antarctic lichen species—Usnea antarctica—in the northern maritime Antarctic, Livingston Island (South Shetland Islands, 62°27′–62°48′S, 59°45′–61°15′W). Here, U. antarctica grows on rocks and forms the dominant vegetation on this site together with a few other macrolichens. This species reproduces mainly by vegetative diaspores (soredia), which include both the photobiont and the mycobiont. To understand the early ontogenetic strategies in U. antarctica, culture experiments were performed in an Antarctic field site where the species occurs naturally. This paper focuses on the different developmental steps seen between the initial colonization of soredia to the formation of a small well-developed thallus, and also on the growth rate of the respective juvenile stages. Compared with growth rates of lichens from temperate European regions the early development of U. antarctica is extraordinarily slow, taking 5–6 years until an adult thallus has been formed. The low photobiont content in the juvenile stages probably limits the growth rate. It is suggested that juvenile development of U. antarctica is controlled by a combination of ecophysiological and morphological adaptations that are required for success in extreme environments such as the terrestrial habitats of the Antarctic.
Biometric data on hawksbill turtles (Eretmochelys imbricata) nesting at Cousine Island, Seychelles
Authors: Hitchins P. M. , Bourquin O. , Hitchins S. , Piper S. E.
Published: November 2004

Nesting hawksbill turtles Eretmochelys imbricata and their eggs and young were studied on Cousine Island, Seychelles from 1995 to 1999. Numbers of females known to nest (tagged individuals) on Cousine was 146. An average of 75% of emerging adults were intercepted, and this rose to 81.6% in 1999. Mean carapace lengths and widths of adult females were 81.2 ± 60.8 cm, and included some of the longest carapace lengths known for hawksbill turtles. There were poor correlations between adult weight and carapace length or width, but better correlations between adult weight and the product of carapace length and width. Width to length carapace proportions averaged 0.75. The mean weight of nesting females before their first recorded nesting on Cousine was 65.6 kg (51.2–83.0 kg). These were the first recorded weights for nesting hawksbills from the Seychelles. Individuals lose 8.5–15% of their body weight after laying three to five clutches. Mean clutch size was 176.7, and clutch sizes for any season showed great variation for some individuals. Clutch sizes tended to decrease after the main nesting month for the population but not necessarily for the individual. The largest clutch size of 264 is the largest recorded for hawksbill turtles worldwide. Turtles with longer carapaces tended to lay larger clutches than those with shorter carapaces, and heavier turtles generally laid heavier clutches than did lighter turtles. Eggs were usually (85.6%) somewhat elongate, measuring on average 36.3 ± 35.5 mm, and weights averaged 25.5 g. Very few ‘pea’ eggs were found. The average hatchling weight was 14.5 g and the average carapace length and width were 39.2 and 30.1 mm, giving a mean ratio of carapace length to width of 0.77.
The effects of prey availability on pup mortality and the timing of birth of South American sea lions (Otaria flavescens) in Peru
Authors: Soto Karim H. , Trites Andrew W. , Arias‐Schreiber Milena
Published: November 2004

Pup mortality and the timing of birth of South American sea lions Otaria flavescens were investigated to determine the possible relationship between fluctuations in prey availability in the Peruvian upwelling ecosystem and current and future reproductive success of sea lions during six consecutive breeding seasons. Our study from 1997 to 2002 encompassed the strongest El Niño on record and one La Niña event. Pup mortality ranged from 13% before El Niño to 100% during El Niño, and was negatively correlated with prey availability. Abortions were also more frequent when prey availability was low. However, pup mortality remained high following El Niño due to the punctuated short‐term effects it had on population dynamics and subsequent maternal behaviour. Births occurred later in the season after years of low food availability and earlier following years of high food availability. The peak of pupping occurred around the peak of mortality in all years, and may have been the product of intensive competition between bulls at the peak of the breeding season. The stronger and more frequent El Niños that appear to be occurring along the Peruvian coast may produce significant stochastic changes in future births and pup mortality, which may place the vulnerable South American sea lion population in Peru at greater risk.
The Eddy Experiment: GNSS‐R speculometry for directional sea‐roughness retrieval from low altitude aircraft
Authors: Germain O. , Ruffini G. , Soulat F. , Caparrini M. , Chapron B. , Silvestrin P.
Published: November 2004

We report the retrieval of sea surface directional mean square slope from Global Navigation Satellite System Reflections (GNSS‐R) Delay‐Doppler‐Map (DDM) data collected during an experimental flight at 1 km altitude. We emphasize the utilization of the entire DDM to more precisely infer ocean roughness directional parameters, and argue that the DDM exhibits the impact of both roughness and scatterer velocity. Obtained estimates are analyzed and compared with Jason‐1 measurements, ECMWF numerical weather model outputs and optical data.
Dynamical System Visualization and Analysis Via Performance Maps
Authors: Alpigini James J.
Published: November 2004

Visualization techniques are common in the study of chaotic motion. These techniques range from simple time graphs and phase portraits to robust Julia sets, which are familiar to many as ‘fractal images.’ The utility of the Julia sets rests not in their considerable visual impact, but rather, in the color-coded information that they display about the dynamics of an iterated function. In this paper, a paradigm termed the performance map is presented, which is derived from the familiar Julia set. Performance maps are generated automatically for control or other dynamical system models over ranges of system parameters. The resulting visualizations require a minimum of a priori knowledge of the system under evaluation. By the use of color-coding, these images convey a wealth of information to the informed user about dynamic behaviors of a system that may be hidden from all but the expert analyst.
Broken-symmetry unrestricted hybrid density functional calculations on nickel dimer and nickel hydride
Authors: Diaconu Cristian V. , Cho Art E. , Doll J. D. , Freeman David L.
Published: November 2004

In the present work we investigate the adequacy of broken-symmetry unrestricted density functional theory for constructing the potential energy curve of nickel dimer and nickel hydride, as a model for larger bare and hydrogenated nickel cluster calculations. We use three hybrid functionals: the popular B3LYP, Becke’s newest optimized functional Becke98, and the simple FSLYP functional (50% Hartree–Fock and 50% Slater exchange and LYP gradient-corrected correlation functional) with two basis sets: all-electron (AE) Wachters+f basis set and Stuttgart RSC effective core potential (ECP) and basis set. We find that, overall, the best agreement with experiment, comparable to that of the high-level CASPT2, is obtained with B3LYP/AE, closely followed by Becke98/AE and Becke98/ECP. FSLYP/AE and B3LYP/ECP give slightly worse agreement with experiment, and FSLYP/ECP is the only method among the ones we studied that gives an unacceptably large error, underestimating the dissociation energy of Ni2 by 28%, and being in the largest disagreement with the experiment and the other theoretical predictions. We also find that for Ni2, the spin projection for the broken-symmetry unrestricted singlet states changes the ordering of the states, but the splittings are less than 10 meV. All our calculations predict a δδ-hole ground state for Ni2 and δ-hole ground state for NiH. Upon spin projection of the singlet state of Ni2, almost all of our calculations: Becke98 and FSLYP both AE and ECP and B3LYP/AE predict (dx2−y2Adx2−y2B)1 or (dxyAdxyB)1 ground state, which is a mixture of Σg+1 and Γg1. B3LYP/ECP predicts a (dx2−y2AdxyB)3 (mixture of Σg-3 and Γu3) ground state virtually degenerate with the (dx2−y2Adx2−y2B)1/(dxyAdxyB)1 state. The doublet δ-hole ground state of NiH predicted by all our calculations is in agreement with the experimentally predicted Δ2 ground state. For Ni2, all our results are consistent with the experimentally predicted ground state of 0g+ (a mixture of Σg+3 and Σg-3) or 0u− (a mixture of Σg-1 and Σg+3).
Frequency- and time-domain femtosecond vibrational sum frequency generation from CO adsorbed on Pt(111)
Authors: Roeterdink W. G. , Berg O. , Bonn M.
Published: November 2004

We have studied the effects of intermolecular and intramolecular coupling on the C–O stretching vibration of CO adsorbed on Platinum (111) by means of femtosecond broadband vibrational sum frequency generation (VSFG). Resonant intermolecular coupling is investigated through the coverage dependence of the VSFG signal. The experimental observations can be accurately modeled as lateral coupling of the molecular transition dipole moments; this coupling is invoked in the nonlinear optical response model as a local field correction. The linear polarizability, which appears in this model, is modified by both the dipole-dipole coupling and the population of bridged adsorption sites. By extending the formalism to include these effects, we deduce a vibrational polarizability of 0.32 Å3 from the data. Intramolecular coupling to the frustrated translational mode is observed as temperature dependence of the C–O stretch. The present data can be described either by pertubative or nonpertubative lineshape models from the literature. Measurements of the temperature dependence of the vibrational free induction decay indicate a population relaxation time T1 of (0.8±0.1) ps, in agreement with the observed low-temperature linewidth. Moreover, the ability of this time-domain method to discriminate spectral inhomogeneity yields clear evidence of the order-disorder transition near 275 K. Above this temperature an inhomogeneous linewidth component of (12±3) cm−1 is observed. This value allows us to estimate the structural heterogeneity of the disordered phase, which result agrees with published Monte Carlo simulations.
Ultrafast excited state dynamics of the Na3F cluster: Quantum wave packet and classical trajectory calculations compared to experimental results
Authors: Heitz M.-C. , Durand G. , Spiegelman F. , Meier C. , Mitrić R. , Bonac̆ić-Koutecký V.
Published: November 2004

Short-time, excited-state dynamics of the lowest isomer of the Na3F cluster is studied theoretically in order to interpret the features of recent time-resolved pump-probe ionization experiments [J. M. L’Hermite, V. Blanchet, A. Le Padellec, B. Lamory, and P. Labastie, Eur. Phys. J. D 28, 361 (2004)]. In the present paper, we propose an identification of the vibrational motion responsible for the oscillations in the ion signal, on the basis of quantum mechanical wave packet propagations and classical trajectory calculations. The good agreement between experiment and theory allows for a clear interpretation of the detected dynamics.
Collisional deexcitation of optically allowed excited atoms by axially symmetric molecules
Authors: Watanabe Tsutomu , Stener Mauro
Published: November 2004

The deexcitation process of an atom in an optically allowed excited state by a collision with an axially symmetric molecule is considered. In order to make a precise comparison with experimental data that have recently been obtained, we extend previous work for a Penning ionization process [T. Watanabe and K. Katsuura, J. Chem. Phys. 47, 800 (1967)]. Using the straight-line trajectory impact parameter method, the probability of deexcitation in the incident atom is described by a discrete-continuum excitation transfer mechanism. The effects of the ionization yield η in molecular target and of the molecular anisotropic property of the optical transition dipole are considered. The cross-section formula σ is presented by a similar formula for Penning ionization of the atomic target by introducing a stereo factor C(λ) as σ=C(λ)[e4μ2μE,⊥2/(4πε0)2ℏv]2/5. Here, v is the relative velocity of the colliding system and λ is given by the ratio λ=(μE∥/μE⊥), where μ, μE⊥, μE∥ are the transition dipole moments of an excited atom, A→A*, those of a molecule at energy E for the perpendicular component and the parallel component with respect to molecular axis. Applications to He*(21P)+H2 (or D2), Ne*[2p5(2P1/2)3s 1P1]+H2 (or D2) systems and systems of the same projectiles on C6H6, (or C6D6) molecules are made. The results for hydrogen molecules are compared with the experimental data.
Ab Initio calculations and vibrational energy level fits for the lower singlet potential-energy surfaces of C3
Authors: Ahmed Khalil , Balint-Kurti Gabriel G. , Western Colin M.
Published: November 2004

Ab initio multireference configuration interaction potential energy surfaces are computed for the eight lowest singlet surfaces of C3. These reveal several important features, including several conical intersections in linear, nonlinear, and equilateral triangle geometries. These intersections are important because, particularly for the excited Ã 1Πu state, reasonable ab initio results could only be obtained by including nearby, near degenerate, Σu−1 and Δu1 states that cross the Ã 1Πu state around 4500 cm−1 above the equilibrium geometry, and a Πg1 state whose potential in turn crosses the other states about 2000 cm−1 further up. These states are probably responsible for the complexity of the shorter wavelength UV absorption spectrum of C3. The computed potential energy surface for the ground, X̃ 1Σg+, state and for the lowest two excited singlet surfaces (which both correlate with the Ã 1Πu state in a collinear geometry) are fitted to analytic functional forms. Vibrational energy levels are calculated for both states, taking account of the Renner-Teller coupling in the excited Ã 1Πu state. The potential parameters for both states are then least-squares fitted to experimental data. The ground-state fit covers a range of ∼8500 cm−1 above the lowest level, and reproduces 100 observed vibrational levels with an average error of 2.8 cm−1. The Ã 1Πu state surfaces cover a range of 3250 cm−1 above the zero-point level, and reproduce the 44 observed levels in this range with an average error of 2.8 cm−1.
Intrinsic and extrinsic factors in anion electron-stimulated desorption: D− from deuterated hydrocarbons condensed on Kr and water ice films
Authors: Możejko Paweł , Bass Andrew D. , Parenteau Luc , Sanche Léon
Published: November 2004

The results of D− ion desorption induced by 3–20 eV electrons incident on condensed CD4, C2D6, C3D8, C2D4, and C2D2 are presented. These compounds were deposited in submonolayer amounts on the surfaces of multilayer solid films of Kr and nonporous and porous amorphous ice. While desorption of the D− anions proceeds via well-known processes, i.e., dissociative electron attachment (DEA) and dipolar dissociation, significant perturbations of these processes due to presence of the different film substrates are observed. We have shown that it is possible to distinguish between the character and nature of these perturbations. The presence of the nonporous ice perturbs the D− desorption intensity by affecting the intrinsic properties of the intermediate anion states through which dissociation proceeds. On the other hand, the presence of the porous ice introduces extrinsic effects, which can affect electron energy losses prior to their interaction with the hydrocarbon molecule and/or the energies and intensities of the fragment species after dissociation. Simple mechanisms responsible for the observed variations in the intensities of desorbed anionic signals are proposed and discussed. Electron transfer from transient anion states to electron states of the substrate film or nearby hydrocarbon molecules appear as the most efficient mechanism to reduce the magnitude of the DEA process.
Effect of cation distribution on self-diffusion of molecular hydrogen in Na3Al3Si3O12 sodalite: A molecular dynamics study
Authors: van den Berg A. W. C. , Bromley S. T. , Flikkema E. , Jansen J. C.
Published: November 2004

The diffusion of hydrogen in sodium aluminum sodalite (NaAlSi-SOD) is modeled using classical molecular dynamics, allowing for full flexibility of the host framework, in the temperature range 800–1200 K. From these simulations, the self-diffusion coefficient is determined as a function of temperature and the hydrogen uptake at low equilibrium hydrogen concentration is estimated at 573 K. The influence of the cation distribution over the framework on the hydrogen self-diffusion is investigated by comparing results employing a low energy fully ordered cation distribution with those obtained using a less ordered distribution. The cation distribution is found to have a surprisingly large influence on the diffusion, which appears to be due to the difference in framework flexibility for different cation distributions, the occurrence of correlated hopping in case of the ordered distribution, and the different nature of the diffusion processes in both systems. Compared to our previously reported calculations on all silica sodalite (all-Si-SOD), the hydrogen diffusion coefficient of sodium aluminum sodalite is higher in the case of the ordered distribution and lower in case of the disordered distribution. The hydrogen uptake rates of all-Si-SOD and NaSiAl-SOD are comparable at high temperatures (∼1000 K) and lower for all-Si-SOD at lower temperatures (∼400 K).
Solution combustion derived nanocrystalline Zn2SiO4:Mn phosphors: A spectroscopic view
Authors: Sreekanth Chakradhar R. P. , Nagabhushana B. M. , Chandrappa G. T. , Ramesh K. P. , Rao J. L.
Published: November 2004

Manganese doped nanocrystalline willemite powder phosphors Zn2−xMnxSiO4 (0.1⩽x⩽0.5) have been synthesized by a low-temperature initiated, self-propagating, gas producing solution combustion process. The phosphors have been characterized by using x-ray diffraction (XRD), energy dispersive spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR), and photo luminescence (PL) spectroscopic techniques. The lattice parameters calculated from XRD confirm that Zn2−xMnxSiO4 has a rhombohedral space group R3̄H. The XRD patterns confirm that Zn2−xMnxSiO4 phosphor samples undergo a phase transformation from β-willemite to α-willemite phase at 950 °C. The EPR spectra of Mn2+ ions exhibit resonance signals at g≅3.24 and g≅2.02, with a sextet hyperfine structure centered around g≅2.02. The EPR signals of Mn2+ give a clear indication of the presence of two different Mn2+ sites. The magnitude of the hyperfine splitting (A) indicates that the Mn2+ is in an ionic environment. The number of spins participating in resonance (N), the paramagnetic susceptibility (χ), and the zero-field splitting parameter (D) have been evaluated as function of x. It is interesting to observe that the variation of N with temperature obeys Boltzmann. The paramagnetic susceptibility is calculated from the EPR data at various temperatures and the Curie constant and Curie paramagnetic temperature was evaluated from the 1/χ versus T graph. The luminescence of Mn2+ ion in Zn2SiO4 shows a strong green emission peak around 520 nm from the synthesized phosphor particles under UV excitation (251 nm). The luminescence is assigned to a transition from the upper T14→A16 ground state. The mechanism involved in the generation of a green emission has been explained in detail. The effect of Mn content on luminescence has also been studied.
Molecular potential energy surfaces by interpolation: Strategies for faster convergence
Authors: Moyano Gloria E. , Collins Michael A.
Published: November 2004

A method for interpolating molecular potential energy surfaces introduced [Ischtwan and Collins, J. Chem. Phys. 100, 8080 (1994)] and developed as an iterative scheme has been improved by different criteria for the selection of the data points. Refinements in the selection procedure are based on the variance of the interpolation and the direct exploration of the interpolation error, and produce more accurate surfaces than the previously established scheme for the same number of data points.
Density functional study of the adsorption of propene on mixed gold-silver clusters, AunAgm: Propensity rules for binding
Authors: Chrétien Steeve , Gordon Mark S. , Metiu Horia
Published: November 2004

We use density functional theory to investigate the binding of propene to small mixed Au–Ag clusters, in the gas phase. We have found that the rules proposed by us for propene binding to Au and Ag clusters, also work for binding to mixed Au–Ag clusters. The rules state that propene binds to those sites on the edge of the cluster where the equal density plots of the LUMO of the naked cluster protrude into the vacuum. Furthermore, the desorption energy of propene correlate with the LUMO energy: the lower the LUMO energy, the stronger the propene bond. We have also found an additional rule that is specific to mixed clusters. We call active the atoms on which the LUMO of the naked cluster protrude in the vacuum, and inactive those for which such protrusions do not exist. To define the rules we use the following notation: A is an active site to which propene is bound B is another active site, and C is an inactive site. If the atom in C (Ag or Au) is replaced with another atom (Au or Ag) propene desorption energy changes very little. If we replace the atom B with a more electronegative atom (i.e., we replace Ag by Au) the propene bond to A becomes stronger. If we replace the atom B with a less electronegative atom (i.e., we replace Au by Ag) the propene bond to A becomes weaker.
Photoionization and photodissociation dynamics of the B 1Σu+ and C 1Πu states of H2 and D2
Authors: Aguirre F. , Pratt S. T.
Published: November 2004

The photoionization and photodissociation dynamics of H2 and D2 in selected rovibrational levels of the B 1Σu+ and C 1Πu states have been investigated by velocity map ion imaging. The selected rotational levels of the B 1Σu+ and C 1Πu states are prepared by three-photon excitation from the ground state. The absorption of fourth photon results in photoionization to produce H2+ X 2Σg+ or photodissociation to produce a ground-state H(1s) atom and an excited H atom with n⩾2. The H2+ ion can be photodissociated by absorption of a fifth photon. The resulting H+ or D+ ion images provide information on the vibrational state dependence of the photodissociation angular distribution of the molecular ion. The excited H(n⩾2) atoms produced by the neutral dissociation process can also be ionized by the absorption of a fifth photon. The resulting ion images provide insight into the excited state branching ratios and angular distributions of the neutral photodissociation process. While the experimental ion images contain information on both the ionic and neutral processes, these can be separated based on constraints imposed on the fragment translational energies. The angular distribution of the rings in the ion images indicates that the neutral dissociation of molecular hydrogen and its isotopes is quite complex, and involves coupling to both doubly excited electronic states and the dissociation continua of singly excited Rydberg states.
Strong light fields coax intramolecular reactions on femtosecond time scales
Authors: Krishnamurthy M. , Rajgara F. A. , Mathur D.
Published: November 2004

Energetic H2+ ions are formed as a result of intramolecular rearrangement during fragmentation of linear alcohols (methanol, ethanol, propanol, hexanol, and dodecanol) induced by intense, pulsed optical fields. The laser intensity regime that is accessed in these experiments (peak intensity of 8×1015 W cm−2) ensures multiple ionization of the irradiated alcohol molecules such that Coulomb explosions would be expected to dominate the overall fragmentation dynamics. Polarization dependent measurements show, counterintuitively, that rearrangement is induced by the strong optical field within a single, 100 fs long laser pulse, and that it occurs before Coulomb explosion of the field-ionized multiply charged alcohols.
A comparison of perceived control beliefs between Chinese and American students
Authors: Liu Yuming , Yussen Steven R.
Published: November 2004

This study examines the developmental patterns of perceived control beliefs among a total of 1720 urban Chinese, rural Chinese, and American students in second through sixth grade. Children’s perceived control beliefs were measured with the Revised Control, Agency, and Means-end Interview (CAMI). The results show that the latent structures of perceived control beliefs were comparable among the three groups of students. The increase in grade level was more important than cultural differences in the development of agency and global control expectancy beliefs. However, there was no evidence that the increase in grade level was more important than cultural differences in the development of means-end beliefs. The developmental patterns of global control expectancy and agency beliefs were similar between Chinese and American students across the elementary school years. The correlations between global control expectancy and the dimensions of agency beliefs and school performance were stronger than those between the dimensions of means-end beliefs and school performance among the three groups of students. Also, the relationships between the dimensions of perceived control beliefs and performance were stronger in language arts than in math. The unique features of the perceptions of “luck”, “ability”, and “effort” among Chinese students were also discussed in terms of the alternative bases of philosophy and religion, the nature of school feedback, and the likelihood of quality experiences in parent–child mediated interactions.
Infants’ search for hidden persons
Authors: Krøjgaard Peter
Published: November 2004

The present article is a review of infants’ search for hidden persons. Studies investigating the presence of the so-called positive decalage—the claim, originating from Piaget, that person permanence precedes object permanence—are presented and discussed. Attempts are made to pinpoint, clarify, and summarise the potential confounding variables that have troubled this field of research (e.g., different object sizes; different search demands; confusing familiarity and motivational aspects). It is argued that Piaget’s term positive decalage is inadequate considering the existing data, and an alternative approach to infants’ search for hidden persons, a time table approach, is presented. Finally, directions for future research and specific studies are proposed.
Loss of Rereplication Control inSaccharomyces cerevisiaeResults in Extensive DNA Damage
Authors: Green Brian M. , Li Joachim J.
Published: November 2004

To maintain genome stability, the entire genome of a eukaryotic cell must be replicated once and only once per cell cycle. In many organisms, multiple overlapping mechanisms block rereplication, but the consequences of deregulating these mechanisms are poorly understood. Here, we show that disrupting these controls in the budding yeast Saccharomyces cerevisiae rapidly blocks cell proliferation. Rereplicating cells activate the classical DNA damage-induced checkpoint response, which depends on the BRCA1 C-terminus checkpoint protein Rad9. In contrast, Mrc1, a checkpoint protein required for recognition of replication stress, does not play a role in the response to rereplication. Strikingly, rereplicating cells accumulate subchromosomal DNA breakage products. These rapid and severe consequences suggest that even limited and sporadic rereplication could threaten the genome with significant damage. Hence, even subtle disruptions in the cell cycle regulation of DNA replication may predispose cells to the genomic instability associated with tumorigenesis.
Silanus 〈and〉 Murena (I.Priene121)
Authors: Eilers Claude
Published: November 2004

An inscription from Priene, first published at the beginning of this century, honours a local citizen who had among other accomplishments conducted a series of embassies to Roman officials in Asia. The text was originally published by Hiller von Gaertringen, though (as we shall see) his interpretation of it was unsatisfactory in at least one respect.
Lucretius, D.R.N. 5.948
Authors: Allen Archibald
Published: November 2004

In his account of primitive people in D.R.N. 5 Lucretius says that they led a wandering, nomadic sort of existence (932, ‘vulgivago vitam tractabant more ferarum’); ignorant of agriculture and husbandry, they were content to eat nuts and berries and the like (933ff.), while streams and springs called them to quench their thirst (945ff.):

denique nota vagis silvestria templa tenebant

nympharum…

The rest of the sentence is a lush description of the streams which welled up from those woodland shrines, washing over rocks and moss, and sometimes breaking out over the plain (949–52).
Chains of imagery in Prometheus Bound
Authors: Mossman J. M.
Published: November 2004

Aeschylus' imagery has for some time now been discussed as a feature of his dramatic technique which does more than merely adorn his work. Lebeck, for example, has described how images articulate the Oresteia:

The images of the Oresteia are not isolated units which can be examined separately. Each one is part of a larger whole: a system of kindred imagery. They are connected to one another by verbal similarity rather than verbal duplication. Formulaic (verbatim) repetition is rare, except in the cases of single ‘key’ words; it is replaced by associative or reminiscent repetition. Such repetition may evoke several different passages, yet correspond exactly to none. Each occurrence adds a new element to those with which it is associated. Often this expansion will be a blend of two images previously separate, preserving features reminiscent of both. In this way the different systems of imagery are intricately interwoven. The significance of a recurrent image unfolds in successive stages, keeping time with the action of the drama.
Phaidra's pleasurableaidos(Eur.Hipp. 380–7)
Authors: Furley W. D.
Published: November 2004

Rather than apologize for taking up this battered subject once again, let me compare scholarly treatment of the passage to such ancient rites as singing theskolion, where every member of the symposium was supposed to give his variant of a given theme. First we must have the passage before us. Phaidra, after first appearing on stage in a delirium where her speech is by no means coherent, addresses the chorus of women of Troizen from line 373 on in rational terms, explaining her predicament and behaviour. Peoples' lives, she says, are not ruined by lack of intelligence, but by failure to live up to their recognition of right and wrong. Some fail to realize (381 ⋯κπονεῖν) their high ideals through laziness or inertia (381 ⋯ργ⋯ας ὓπο), others by putting some dubious pleasure before the good (382–3 οἱ δ' ⋯δον⋯ν προθέντες ⋯ντ⋯ το⋯ καλο⋯ / ἂλλην τιν').
Writing, copying, and autograph manuscripts in ancient Rome
Authors: Mcdonnell Myles
Published: November 2004

A familiar image from the Roman world is a Pompeian portrait of a man and woman sometimes identified as Terentius Neo and his wife. He has a papyrus roll under his chin, while she looks out with a writing tablet in one hand, a stylus held to her lips in the other. The message of the attributes presented would seem to be: ‘ We can and do read and write’. But how should the message be interpreted? To judge from the houses in which this and similar portraits were found, the couple was not of the elite decurion class, but belonged to that difficult to define group of varying social, economic and cultural statuses recently described by Keith Hopkins as ‘sub-elites’. Does the display of book and pen then reflect the social reality of the sub-elite orders of Pompeian society, or is the self-representation rather an expression of social pretension, with the couple attempting to emulate the Roman elite? If the latter is the case, what does the image say about the habits of the Roman ruling class? This question has been raised in relation to the issue of literacy, particularly women's literacy, but the image invites another question.
Diiudicatio locorum: Gellius and the history of a mode in ancient comparative criticism
Authors: Vardi Amiel D.
Published: November 2004

Comparison of literary passages is a critical procedure much favoured by Gellius, and is the main theme in several chapters of hisNoctes Atticae: ch. 2.23 is dedicated to a comparison of Menander's and Caecilius′ versions of thePlocium; 2.27 to a confrontation of passages from Demosthenes and Sallust; in 9.9 Vergilian verses are compared with their originals in Theocritus and Homer; parts of speeches by the elder Cato, C. Gracchus and Cicero are contrasted in 10.3; two of Vergil's verses are again compared with their supposed models in ch. 11.4; a segment of Ennius′ Hecuba is contrasted with its Euripidean original in 13.27; Cato's and Musonius′ formulations of a similarsententiaare confronted in 16.1; in 17.10 Vergil's description of Etna is compared to Pindar's; the value of Latin erotic poetry is weighed against the Greek in ch. 19.9, in which an Anacreontean poem and four Latin epigrams are cited; and finally in 19.11 a ‘Platonic' distich is set side by side with its Latin adaptation, composed by an anonymous friend of Gellius, though in this case no comparison of the poems is attempted.
Hipponicus‘ Trapeza: humour in Andocides 1.130–1
Authors: Cox Cheryl Anne
Published: November 2004

Andocides is generally not considered one of the best orators. To point up his flawed style, scholars have discussed a notoriously vindictive and humorous section in Andocides 1: in 124ff. Andocides describes the profligate lifestyle of his prosecutor, Callias III the Ceryx, the son of Hipponicus II anddadouchosof the Eleusinian Mysteries.