bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pediatric nasopharyngeal carcinoma: Better prognosis and increased c‐Kit expression as compared to adults
Authors: Bar‐Sela Gil , Arush Myriam Weyl Ben , Sabo Edmond , Kuten Abraham , Minkov Ira , Ben‐Izhak Ofer 
Published: November 2004

AbstractIntroductionNasopharyngeal carcinoma (NPC) in children is distinguishable from the adult form by its close association with Epstein‐Barr virus (EBV) infection, a higher rate of undifferentiated histology, and a greater incidence of advanced locoregional disease.Patients and MethodsSixteen NPC patients, ≤20 years of age were identified from our 1976–2001 tumor registry records. Clinical stage, treatment, recurrence, and survival were evaluated. Sections were stained by immunohistochemistry for p53, Bcl‐2, Ki67, and c‐Kit and by in situ hybridization for EBER. Obtained data were compared to 32 adult patients. All patients had undifferentiated or non‐keratinizing NPC.ResultsEBER was positive in 100% of children, compared to 90% of adults. Comparing children to adults, median Ki67 index was 49% and 30%, p53 positive tumors were 69% and 94%, positive Bcl‐2 was 63% and 72%, and positive c‐Kit was 88% and 28%, respectively.ConclusionNo parameter had significant predictive values for survival, although c‐Kit expression had a trend for better prognosis in the pediatric group. By univariate analysis of all 48 cases, positive c‐Kit was associated with better survival (P = 0.029), largely due to the better survival of the pediatric group. By multivariate analysis, increased stage (P = 0.006) and older age (P = 0.044) correlated with worse prognosis. © 2004 Wiley‐Liss, Inc.
RNA expression analysis of a congenital intracranial teratoma
Authors: Yokoi Kentaro , Akiyama Masaharu , Yanagisawa Takaaki , Yoshino Masami , Nakazaki Hiromichi , Takahashi Koichi , Takahashi‐Fujigasaki Junko , Kanetsuna Yukiko , Yamada Hisashi , Oi Shizuo , Eto Yoshikatsu 
Published: November 2004

AbstractCongenital intracranial tumors are extremely rare and account only for 0.5%–1.5% of brain tumors in children. We report a large intrauterine congenital teratoma in a female fetus at gestation weeks 37, which was diagnosed by detecting the tumor and associated craniomegaly with ultrasonography (US) and magnetic resonance (MR) imaging. The tumor had replaced the cerebral hemispheres and produced prenatal manifestations. Pathologic examination showed an immature teratoma, which was differentiated from all three germ layers. Microarray analysis revealed upregulation of ten genes and downregulation of three genes, as well as upregulation of 41 genes of ribosomal proteins in teratoma cells, compared to normal brain tissue of the patient. The data from the microarray analysis offer not only the potential to help define disease pathogenesis but may also provide clues to identify potential molecular therapeutic targets. © 2004 Wiley‐Liss, Inc.
A molecular dynamics study of the structural stability of HIV‐1 protease under physiological conditions: The role of Na+ ions in stabilizing the active site
Authors: Kovalskyy Dmytro , Dubyna Volodymyr , Mark Alan E. , Kornelyuk Alexander 
Published: November 2004

AbstractHIV‐1 protease is most active under weakly acidic conditions (pH 3.5–6.5), when the catalytic Asp25 and Asp25′ residues share 1 proton. At neutral pH, this proton is lost and the stability of the structure is reduced. Here we present an investigation of the effect of pH on the dynamics of HIV‐1 protease using MD simulation techniques. MD simulations of the solvated HIV‐1 protease with the Asp25/25′ residues monoprotonated and deprotonated have been performed. In addition we investigated the effect of the inclusion of Na+ and Cl− ions to mimic physiological salt conditions. The simulations of the monoprotonated form and deprotonated form including Na+ show very similar behavior. In both cases the protein remained stable in the compact, “self‐blocked” conformation in which the active site is blocked by the tips of the flaps. In the deprotonated system a Na+ ion binds tightly to the catalytic dyad shielding the repulsion between the COO− groups. Ab initio calculations also suggest the geometry of the active site with the Na+ bound closely resembles that of the monoprotonated case. In the simulations of the deprotonated form (without Na+ ions), a water molecule bound between the Asp25 Asp25′ side‐chains. This disrupted the dimerization interface and eventually led to a fully open conformation. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Ground states of BeC and MgC: A comparative multireference Brillouin–Wigner coupled cluster and configuration interaction study
Authors: Teberekidis Vasilios I. , Kerkines Ioannis S. K. , Tsipis Constantinos A. , Čársky Petr , Mavridis Aristides 
Published: November 2004

AbstractThe competing X3Σ− and 5Σ− states of the experimentally unknown alkaline–earth metal carbides BeC and MgC are examined with the multireference Brillouin–Wigner coupled cluster method restricted to single and double excitations (MRBW‐CCSD). The results are compared against the traditional single‐reference CCSD approach, as well as with other single and multireference methods. In both molecules, the CCSD 5Σ− ← X3Σ− energy difference is underestimated, leading to an “erroneous” ground‐state prediction in BeC. The MRBW‐CCSD method corrects this anomalous behavior, leading to fair agreement with multireference configuration interaction (MR‐CI) predictions. Our results at the highest levels of theory are extrapolated to the basis set limit, and the core/valence correlation is taken into account, leading to very accurate energetics and spectroscopic constants in both carbides. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
How complex are random graphs in first order logic?
Authors: Kim Jeong Han , Pikhurko Oleg , Spencer Joel H. , Verbitsky Oleg 
Published: November 2004

AbstractIt is not hard to write a first order formula which is true for a given graph G but is false for any graph not isomorphic to G. The smallest number D(G) of nested quantifiers in such a formula can serve as a measure for the “first order complexity” of G. Here, this parameter is studied for random graphs. We determine it asymptotically when the edge probability p is constant; in fact, D(G) is of order log n then. For very sparse graphs its magnitude is Θ(n). On the other hand, for certain (carefully chosen) values of p the parameter D(G) can drop down to the very slow growing function log* n, the inverse of the TOWER‐function. The general picture, however, is still a mystery. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Nematode diversity in the Gulf of Maine, USA, and a Web-accessible, relational database
Authors: Abebe Eyualem , E. Grizzle Raymond , Hope Duane , K. Thomas William 
Published: November 2004

Nematode assemblages were studied from four sublittoral sites at 50–56 m depth in the Gulf of Maine, north-eastern coast of the USA, within the context of an open ocean aquaculture experimental site. All four sites, two potential impact and two control sites, had a similar muddy–sand bottom and low organic content. Seventy genera in 27 families were recorded from a total of 1072 individuals. All but one taxa could be related to known genera. Family Comesomatidae was the most dominant with close to a third (27·6%) of the total individuals. At the genus level Sabatieria and Setosabatieria were most dominant with a quarter of the total number of individuals. Composition of dominant families from the Gulf of Maine differed from all hitherto reported sublittoral or deep-sea communities from both sides of the Atlantic, and most similar with European estuaries.Nematode diversity at the genus-level was reasonably high and was comparable with Mediterranean samples. Most diversity indices ordered the four sites similarly with Site 2 as the most diverse followed by Site 5 and then Site 6. By contrast the relative diversity of Site 4 depended on the index employed and its k-dominance curve crossed that of the others. Furthermore based on clustering the community at Site 4 was least similar to the others. Although these observations could be related to the fact that Site 4 is within the expected impact zone of the fish cage, the low number of fish introduced by the time of sampling and the lack of any difference in the maturity index among all the sites argue that these results can be considered before-impact data for further monitoring of the open ocean aquaculture experiment.A new paradigm where morphological information is documented and communicated using digital multifocal images is introduced. Each video image is comparable with visualization of a specimen under a microscope where the movie can be played back and forth to mimic focusing through a specimen. Web-based and openly accessible digital multifocal images were used to document and effectively communicate the morphology of all the identified genera in this study. This approach for documenting and communicating survey results is proposed as a benchmark for future similar studies that would enhance standardization and quality control of meiofaunal taxonomy, ecology and biodiversity studies.
The acetylcholinesterase inhibitor BW284c51 is a potent blocker of Torpedo nicotinic AchRs incorporated into the Xenopus oocyte membrane
Authors: Olivera‐Bravo Silvia , Ivorra Isabel , Morales Andrés 
Published: November 2004

This work was aimed to determine if 1,5‐bis(4‐allyldimethylammoniumphenyl)pentan‐3‐one dibromide (BW284c51), the most selective acetylcholinesterase inhibitor (AchEI), affects the nicotinic acetylcholine (Ach) receptor (AchR) function.
Purified Torpedo nicotinic AchRs were injected into Xenopus laevis oocytes and BW284c51 effects on Ach‐ and carbamylcholine (Cch)‐elicited currents were assessed using the voltage‐clamp technique.
BW284c51 (up to 1 mM) did not evoke any change in the oocyte membrane conductance. When BW284c51 (10 pM–100 μM) and Ach were coapplied, Ach‐evoked currents (IAch) were reversibly inhibited in a concentration‐dependent manner (Hill coefficient, 1; IC50, 0.2–0.5 μM for 0.1–1000 μM Ach). Cch‐elicited currents showed a similar inhibition by BW284c51.
IAch blockade by BW284c51 showed a strong voltage dependence, being only apparent at hyperpolarising potentials. BW284c51 also enhanced IAch desensitisation.
BW284c51 changed the Ach concentration‐dependence curve of Torpedo AchR response from two‐site to single‐site kinetics, without noticeably affecting the EC50 value.
The BW284c51 blocking effect was highly selective for nicotinic over muscarinic receptors. BW284c51 inhibition potency was stronger than that of tacrine, and similar to that of d‐tubocurarine (d‐TC). Coapplication of BW284c51 with either tacrine or d‐TC revealed synergistic inhibitory effects.
Our results indicate that BW284c51 antagonises nicotinic AchRs in a noncompetitive way by blocking the receptor channel, and possibly by other, yet unknown, mechanisms.
Therefore, besides acting as a selective AchEI, BW284c51 constitutes a powerful and reversible blocker of nicotinic AchRs that might be used as a valuable tool for understanding their function.

British Journal of Pharmacology (2005) 144, 88–97. doi:10.1038/sj.bjp.0705965
A 2‐year experimental study on nutrient and predator influences on food web constituents in a shallow lake of north‐west Spain
Authors: Fernández‐Aláez Margarita , Fernández‐Aláez Camino , Bécares Eloy , Valentín María , Goma Joan , Castrillo Pedro 
Published: November 2004

Summary1. A 2‐year study was carried out on the roles of nutrients and fish in determining the plankton communities of a shallow lake in north‐west Spain. Outcomes were different each year depending on the initial conditions, especially of macrophyte biomass. In 1998 estimated initial ‘per cent water volume inhabited’ (PVI) by submerged macrophytes was about 35%. Phytoplankton biomass estimated as chlorophyll a was strongly controlled by fish, whereas effects of nutrient enrichment were not significant. In 1999 estimated PVI was 80%, no fish effect was observed on phytoplankton biomass, but nutrients had significant effects. Water temperatures were higher in 1998 than in 1999.2. In the 1998 experiment, cladoceran populations were controlled by fish and cyanobacteria were the dominant phytoplankton group. There were no differences between effects of low (4 g fresh mass m−2) and high (20 g fresh mass m−2) fish density on total zooplankton biomass, but zooplankton biomass was higher in the absence of fish. With the high plant density in 1999, fish failed to control any group of the zooplankton community.3. Total biovolume of phytoplankton strongly decreased with increased nutrient concentrations in 1998, although chlorophyll a concentrations did not significantly change. At higher nutrient concentrations, flagellate algae became more abundant with likely growth rates that could have overcompensated cladoceran feeding rates. This change in phytoplankton community composition may have been because of increases in the DIN : SRP ratio. Both chlorophyll a concentration and total phytoplankton biovolume increased significantly with nutrients in the 1999 experiment.4. A strong decline of submerged macrophytes was observed in both years as nutrients increased, resulting in shading by periphyton. This shading effect could account for the plant decline despite lower water turbidity at the very high nutrient levels in 1998.
Rooting damage to farmland in Dorset, southern England, caused by feral wild boar Sus scrofa
Authors: WILSON CHARLES J. 
Published: November 2004

ABSTRACT 1. Characteristics of damage to agricultural land caused by a small feral population of wild boar Sus scrofa in southern England were studied. Fifty‐eight reports of rooting damage to grassland and one of rooting in a cereal crop were recorded between December 1997 and November 2002. Most reports (74%) concerned damage in January, February or March. 2. Damage mainly occurred in fields adjacent to woodland, but there was no evidence of selection between different grassland types. The severity of damage was assessed and potential options for reducing damage in the future are suggested.
Market Valuation and Merger Waves
Authors: RHODES‐KROPF MATTHEW , VISWANATHAN S. 
Published: November 2004

ABSTRACTDoes valuation affect mergers? Data suggest that periods of stock merger activity are correlated with high market valuations. The naïve explanation that overvalued bidders wish to use stock is incomplete because targets should not be eager to accept stock. However, we show that potential market value deviations from fundamental values on both sides of the transaction can rationally lead to a correlation between stock merger activity and market valuation. Merger waves and waves of cash and stock purchases can be rationally driven by periods of over‐ and undervaluation of the stock market. Thus, valuation fundamentally impacts mergers.
Collars and Renegotiation in Mergers and Acquisitions
Authors: OFFICER MICAH S. 
Published: November 2004

ABSTRACTI examine the motivation for, and effect of, including a collar in a merger agreement. The most important cross‐sectional determinants of the bid structure (cash vs. stock, and whether to include a collar) are the market‐related stock return standard deviations for the bidder and target. This evidence supports the hypothesis that the method of payment is dependent on the sensitivities of the bidder and target to market‐related risk because either has the incentive to demand renegotiation of the merger terms if the value of the bidder's offer changes materially relative to the value of the target during the bid period.
Luxury Goods and the Equity Premium
Authors: AÏT‐SAHALIA YACINE , PARKER JONATHAN A. , YOGO MOTOHIRO 
Published: November 2004

ABSTRACTThis paper evaluates the equity premium using novel data on the consumption of luxury goods. Specifying utility as a nonhomothetic function of both luxury and basic consumption goods, we derive pricing equations and evaluate the risk of holding equity. Household survey and national accounts data mostly reflect basic consumption, and therefore overstate the risk aversion necessary to match the observed equity premium. The risk aversion implied by the consumption of luxury goods is more than an order of magnitude less than that implied by national accounts data. For the very rich, the equity premium is much less of a puzzle.
The pH 6 Antigen Is an Antiphagocytic Factor Produced byYersinia pestisIndependent ofYersiniaOuter Proteins and Capsule Antigen
Authors: Huang Xiao-Zhe , Lindler Luther E. 
Published: November 2004

ABSTRACTThe pH 6 antigen (pH 6 Ag; PsaA) ofYersinia pestishas been shown to be a virulence factor. In this study, we set out to investigate the possible function ofY. pestisPsaA in a host cell line, RAW264.7 mouse macrophages, in order to better understand the role it might play in virulence.Y. pestisKIM5 derivatives with and without the pCD1 plasmid and theirpsaAisogenic counterparts andEscherichia coliHB101 and DΗ5α carrying apsaAclone or a vector control were used for macrophage infections. Macrophage-related bacteria and gentamicin-resistant intracellular bacteria generated from plate counting and direct microscopic examinations were used to evaluate these RAW264.7 macrophage infections.Y. pestis psaAisogenic strains did not show any significant difference in their abilities to associate with or bind to mouse macrophage cells. However, expression ofpsaAappeared to significantly reduce phagocytosis of bothY. pestisandE. coliby mouse macrophages (P< 0.05). Furthermore, we found that complementation ofpsaAmutantY. pestisstrains could completely restore the ability of the bacteria to resist phagocytosis. Fluorescence microscopy following differential labeling of intracellular and extracellularY. pestisrevealed that significantly lower numbers ofpsaA-expressing bacteria were located inside the macrophages. Enhanced phagocytosis resistance was specific for bacteria expressingpsaAand did not influence the ability of the macrophages to engulf other bacteria. Our data demonstrate thatY. pestispH 6 Ag does not enhance adhesion to mouse macrophages but rather promotes resistance to phagocytosis.
Cytokine and Fibrogenic Gene Expression in the Conjunctivas of Subjects from a Gambian Community Where Trachoma Is Endemic
Authors: Burton Matthew J. , Bailey Robin L. , Jeffries David , Mabey David C. W. , Holland Martin J. 
Published: November 2004

ABSTRACTThe role of immunity in blinding trachoma is unclear. Conjunctival gene expression was measured in a population where trachoma is endemic. Proinflammatory (tumor necrosis factor alpha and interleukin-1β [IL-1β]), anti-inflammatory (IL-10), and fibrogenic (matrix metalloprotease 9) gene expression was increased in active trachoma. Markers indicative of T-cell response (gamma interferon, IL-4, IL-12p40, and perforin) were increased when chlamydial infection was present.
LEARNING RECURSIVE LANGUAGES WITH BOUNDED MIND CHANGES
Authors: LANGE STEFFEN , ZEUGMANN THOMAS 
Published: November 2004

In the present paper we study the learnability of enumerable families ℒ of uniformly recursive languages in dependence on the number of allowed mind changes, i.e. with respect to a well-studied measure of efficiency. We distinguish between exact learnability (ℒ has to be inferred w.r.t. ℒ) and class preserving learning (ℒ has to be inferred w.r.t. some suitable chosen enumeration of all the languages from ℒ) as well as between learning from positive and from both, positive and negative data. The measure of efficiency is applied to prove the superiority of class preserving learning algorithms over exact learning. In particular, we considerably improve results obtained previously and establish two infinite hierarchies. Furthermore, we separate exact and class preserving learning from positive data that avoids overgeneralization. Finally, language learning with a bounded number of mind changes is completely characterized in terms of recursively generable finite sets. These characterizations offer a new method to handle overgeneralizations and resolve an open question of Mukouchi.1
NIRENBERG'S PROBLEM ON THE 2-DIMENSIONAL HEMI-SPHERE
Authors: LIU JIA-QUAN , LI PING-LI 
Published: November 2004

In this paper, Morse theory under general boundary conditions is used to study the Nirenberg's problem on hemi-sphere [Formula: see text]: Given a smooth function K on hemi-sphere [Formula: see text], with the standard metric, whether a conformal metric can be found, so that the Gaussian curvature equals to K and the boundary is again a geodesic curve. It turns out that if deg (Ω, ∂θK, 0) ≠ 1, where [Formula: see text], ∂nK is the exterior normal derivative and ∂θK is the tangential derivative, then the Nirenberg's problem has a solution.
DAPHNE: DATA PARALLELISM NEURAL NETWORK SIMULATOR
Authors: FRASCONI PAOLO , GORI MARCO , SODA GIOVANNI 
Published: November 2004

In this paper we describe the guideline of Daphne, a parallel simulator for supervised recurrent neural networks trained by Backpropagation through time. The simulator has a modular structure, based on a parallel training kernel running on the CM-2 Connection Machine. The training kernel is written in CM Fortran in order to exploit some advantages of the slicewise execution model. The other modules are written in serial C code. They are used for designing and testing the network, and for interfacing with the training data. A dedicated language is available for defining the network architecture, which allows the use of linked modules. The implementation of the learning procedures is based on training example parallelism. This dimension of parallelism has been found to be effective for learning static patterns using feedforward networks. We extend training example parallelism for learning sequences with full recurrent networks. Daphne is mainly conceived for applications in the field of Automatic Speech Recognition, though it can also serve for simulating feedforward networks.
THE MINIMAL LENGTH AND LARGE EXTRA DIMENSIONS
Authors: HOSSENFELDER SABINE 
Published: November 2004

Planck scale physics represents a future challenge, located between particle physics and general relativity. The Planck scale marks a threshold beyond which the old description of spacetime breaks down and conceptually new phenomena must appear. Little is known about the fundamental theory valid at Planckian energies, except that it necessarily seems to imply the occurrence of a minimal length scale, providing a natural ultraviolet cutoff and a limit to the possible resolution of spacetime. Motivated by String Theory, the models of large extra dimensions lower the Planck scale to values soon accessible. These models predict a vast number of quantum gravity effects at the lowered Planck scale, among them the production of TeV-mass black holes and gravitons. Within the extra dimensional scenario, the minimal length also comes into the reach of experiment and sets a fundamental limit to short distance physics. We review the status of Planck scale physics in these effective models.