bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation clustering in neural and social networks
Authors: Puljic Marko , Kozma Robert 
Published: April 2005

AbstractQuestions related to the evolution of the structure of networks have received recently a lot of attention in the literature. But what is the state of the network given its structure? For example, there is the question of how the structures of neural networks make them behave? Or, in the case of a network of humans, the question could be related to the states of humans in general, given the structure of the social network. The models based on stochastic processes developed in this article, do not attempt to capture the fine details of social or neural dynamics. Rather they aim to describe the general relationship between the variables describing the network and the aggregate behavior of the network. A number of nontrivial results are obtained using computer simulations. © 2005 Wiley Periodicals, Inc. Complexity 10: 42–50, 2005
Moon patterns, sun patterns, and wave breaking in rotating granular mixtures
Authors: Hill K. M. , Gioia G. , Amaravadi D. , Winter C. 
Published: April 2005

AbstractGranular materials, such as powders and sand, tend to segregate due to differences in particle properties. When a cylindrical drum is partially filled with particles of different sizes and rotated about its axis, this leads to radial segregation patterns in which the smaller particles concentrate in a radial core near the axis, and the larger particles near the outside walls of the drum. Under certain conditions, undulations in the radial core of smaller particles grow into radial stripes that extend toward the outer walls of the drum in a manner somewhat reminiscent of viscous fingering. The patterns are strongly dependent on the fill level and rotation speed of the drum. These observations can be explained by two spatially disjoint mechanisms: (1) a wave‐breaking mechanism that promotes the growth of the stripes and (2) a filtering mechanism that limits the growth of stripes. © 2005 Wiley Periodicals, Inc. Complexity 10: 79–86, 2005
A New Class of Inhibitors for the Metalloprotease Neprilysin Based on a Central Imidazole Scaffold
Authors: Sahli Stefan , Stump Bernhard , Welti Tobias , Schweizer W. Bernd , Diederich François , Blum‐Kaelin Denise , Aebi Johannes D. , Böhm Hans‐Joachim 
Published: April 2005

AbstractNeprilysin (NEP; neutral endopeptidase EC 3.4.24.11) is a ZnII‐dependent, membrane‐bound endopeptidase. NEP is widely distributed in the organs, particularly in the kidneys and lungs, and it is involved in the metabolism of a number of smaller regulatory peptides. Inhibition of NEP has been proposed as a potential target for analgesic and antihypertensive therapies. In this study, new nonpeptidic inhibitors of neprilysin ((±)‐1, (±)‐43, (±)‐45, and (±)‐46; Table) were designed, based on the X‐ray crystal structure of NEP complexed to phosphoramidon (Fig. 1). They feature an imidazole ring as the central scaffold, acting as a peptide bond isoster to undergo H‐bonding with the side chains of Asn542 and Arg717 (Fig. 2). The scaffold is decorated with a thiol group to ligate to the ZnII ion and two aromatic residues to bind into the hydrophobic S1′ and S2′ pockets. The synthesis of the new inhibitors was approached by two routes (Schemes 1–4 and 5–8), with the second one involving a double directed ortho‐metallation of the imidazole platform and a Stille cross‐coupling, providing the desired target molecules as hydrochloride salts. In a fluorescence assay, inhibitors (±)‐1, (±)‐43, (±)‐45, and (±)‐46 all exhibit IC50 values in the single‐digit micromolar activity range (2–4 μM, Table), which validates the binding mode postulated by modeling. Useful guidelines for a next lead optimization cycle were obtained in several control runs.
Structure Determination of Hydroxytrypargine: A New Tetrahydro‐β‐Carboline Toxin from the Venom of the Spider Parawixia bistriata
Authors: Cesar Lilian M. M. , Tormena Claudio F. , Marques Mauricio R. , Silva Gil V. J. , Mendes Maria A. , Rittner Roberto , Palma Mario S. 
Published: April 2005

AbstractA new, highly active tetrahydro‐β‐carboline toxin from the spider Parawixia bistriata, the most‐common species of social spider occurring in Brazil, was isolated. The new toxin was identified as 1,2,3,4‐tetrahydro‐6‐hydroxy‐β‐carboline (=N‐[3‐(2,3,4,9‐tetrahydro‐6‐hydroxy‐1H‐pyrido[3,4‐b]indol‐1‐yl)propyl]guanidine; 3). This type of alkaloid, not common among spider toxins, was found to be the most‐potent constituent of the spider's chemical weaponry to kill prey. When P. bistriata catch arthropods in their web, they apparently attack their prey in groups of many individuals injecting their venoms. In vivo toxicity assays with 3 demonstrated a potent lethal effect to honeybees, giving rise to clear neurotoxic effects (paralysis) before death. The compound's toxicity (LD50 value) was determined to be ca. 8 ng/g of honeybee. The investigation of the pharmacological properties and neurotoxic actions of 3 may be used in the future for the development of new drugs to be applied for pest control in agriculture.
Chemistry of the Benzotropone Endoperoxides and Their Conversion into Tropolone Derivatives: Unusual Endoperoxide Rearrangements
Authors: Güney Murat , Daştan Arif , Balci Metin 
Published: April 2005

AbstractThe chemistry of two bicyclic endoperoxides, obtained by photooxygenation of 2,3‐benzotropone (=5H‐benzocyclohepten‐5‐one; 5) and of its ethyl carboxylate derivative 15, was investigated with the aim of synthesizing the respective benzotropolone derivatives. The reaction of the endoperoxide 10 derived from 5 with thiourea gave the desired benzotropolone, i.e., 6‐hydroxy‐5H‐benzocyclohepten‐5‐one (11), in high yield (Scheme 1). On the other hand, the endoperoxide 16 derived from the ethyl carboxylate derivative 15 underwent an unprecedented transformation yielding mainly the ring‐contracted lactones 28 and 29 besides the expected substituted benzotropolone derivative 27 (Scheme 5). However, the thermolysis reaction of the same endoperoxide 16 resulted in the formation of four rearranged compounds with different skeletons (Scheme 3). The formation mechanism of all products is discussed (Schemes 4 and 6).
Solvent Role on Cobalt(II) Dioxygen Carriers Based on Simple Polyamine Ligands
Authors: Del Piero Silvia , Ghezzi Lisa , Melchior Andrea , Tiné Maria Rosaria , Tolazzi Marilena 
Published: April 2005

AbstractThe kinetics and thermodynamics of O2 addition to CoII complexes containing the simple triamine ligand (L) diethylenetriamine (=N‐(2‐aminoethyl)ethane‐1,2‐diamine; dien) or N,N″‐dimethyldiethylenetriamine (=N‐methyl‐N′‐[2‐(methylamino)ethyl]ethane‐1,2‐diamine; dmdien) in the aprotic solvent dimethyl sulfoxide (DMSO) were studied by UV/VIS spectrophotometry, potentiometry, and O2 absorption measurements. A parallel investigation on the anaerobic formation of CoII complexes with dmdien, as well as on their reactivity towards O2, was carried out in aqueous 0.1M NaClO4 solution. [CoL]2+ and [CoL2]2+ were the common species formed under anaerobic conditions in both aqueous and DMSO solutions. Under aerobic conditions, O2 adducts of different stoichiometry were formed: a superoxo complex [CoL2O2]2+ in DMSO and dimeric species in H2O. The role of the reaction medium as well as effects of N‐alkylation of the triamine ligand in the formation and reactivity of the [CoII(triamine)] complexes are discussed.
Rapid Determination of Gallamine Triethiodide (Flaxedil®) and Pancuronium Bromide (Pavulon®) in Pharmaceutical and Urine Matrices by Means of Modified‐Carbon‐Paste Ion‐Selective Electrodes
Authors: Salem Alaa A. , Barsoum Barsoum N. , El Said Dalia M. 
Published: April 2005

AbstractA new analytical method for the determination of gallamine triethiodide (Flaxedil®; 1) and pancuronium bromide (Pavulon®; 2), two muscle relaxants used in surgical operations and in pain relief, has been developed. Our approach relies on rapid, precise, and sensitive potentiometric sensors based on modified‐carbon‐paste ion‐selective electrodes (CP‐ISEs). Linear calibration graphs in the working ranges of ca. 4.5–892 and 7.3–733 μg/ml (in H2O, pH 7.0, T=25°) were established for 1 and 2, respectively; and Nernst slopes corresponding to three‐ or two‐electrons transfers, respectively, were obtained. The method works best in a pH range of 7–9. Average relative errors of 2.12 and 2.14%, with average standard deviations of 1.98–2.47 and 2.64–3.45, respectively, were obtained for urine samples of 1 and 2. The corresponding relative errors for the pharmaceutical samples were 1.59 and 1.64%, with standard deviations of 0.54–1.34 and 0.52–1.67, respectively. Statistical Student and F tests were applied to the data, and satisfactory results were obtained.
Two New Ceramides from the Marine Sponge Ircinia fasciculata
Authors: Zhang Guang‐Wen , Ma Xiang‐Quan , Zhang Cui‐Xian , Su Jing‐Yu , Ye Wen‐Cai , Zhang Xiao‐Qi , Yao Xin‐Sheng , Zeng Long‐Mei 
Published: April 2005

AbstractA new 4‐sulfated ceramide, ircisulfamide (=N‐[(1S*,2S*,3R*)‐2‐hydroxy‐1‐(hydroxymethyl)‐3‐(sulfooxy)heptadecyl]hexadecanamide; 1), and a new glycosphingolipid, ircicerebroside (=(2R*)‐N‐{(1S*,2R*,3E,7E)‐1‐[(β‐D‐glucopyranosyloxy)methyl]‐2‐hydroxy‐8‐methylheptadeca‐3,7‐dienyl}‐2‐hydroxyeicosanamide; 2), were isolated from the aqueous EtOH extract of the marine sponge Ircinia fasciculata (Pallas). The structures of the new compounds were elucidated on the basis of spectroscopic analysis and by means of chemical methods.
Synthesis of Caged Nucleosides with Photoremovable Protecting Groups Linked to Intramolecular Antennae
Authors: Smirnova Joulia , Wöll Dominik , Pfleiderer Wolfgang , Steiner Ulrich E. 
Published: April 2005

AbstractBased on the [2‐(2‐nitrophenyl)propoxy]carbonyl (nppoc) group, six new photolabile protecting groups (2, 8, 9b, 16b, 25b, and 26), each covalently linked to a 9H‐thioxanthen‐9‐one (Tx) unit functioning as an intramolecular triplet sensitizer, were synthesized. Linkers were introduced between the Me group or the aromatic ring of nppoc and the 2‐position of Tx by means of classical organic synthesis combined with Pd catalyzed CC coupling reactions. The new photolabile protecting groups to be used in light‐directed synthesis of DNA chips were attached to the 5′‐O‐atom of thymidine via a carbonate linkage, giving rise to the caged nucleosides 7, 11, 13, 19, 20, and 30.
Three‐parameter discontinuous distributions for hydrological samples with zero values
Authors: Weglarczyk Stanislaw , Strupczewski Witold G. , Singh Vijay P. 
Published: April 2005

AbstractA consistent approach to the frequency analysis of hydrologic data in arid and semiarid regions, i.e. the data series containing several zero values (e.g. monthly precipitation in dry seasons, annual peak flow discharges, etc.), requires using discontinuous probability distribution functions. Such an approach has received relatively limited attention. Along the lines of physically based models, the extensions of the Muskingum‐based models to three parameter forms are considered. Using 44 peak flow series from the USGS data bank, the fitting ability of four three‐parameter models was investigated: (1) the Dirac delta combined with Gamma distribution; (2) the Dirac delta combined with two‐parameter generalized Pareto distribution; (3) the Dirac delta combined with two‐parameter Weibull (DWe) distribution; (4) the kinematic diffusion with one additional parameter that controls the probability of the zero event (KD3). The goodness of fit of the models was assessed and compared both by evaluation of discrepancies between the results of both estimation methods (i.e. the method of moments (MOM) and the maximum likelihood method (MLM)) and using the log of likelihood function as a criterion. In most cases, the DWe distribution with MLM‐estimated parameters showed the best fit of all the three‐parameter models. Copyright © 2005 John Wiley & Sons, Ltd.
Heavy metal release by peat erosion in the Peak District, southern Pennines, UK
Authors: Rothwell J. J. , Robinson S. G. , Evans M. G. , Yang J. , Allott T. E. H. 
Published: April 2005

AbstractUpper North Grain (UNG) is a heavily eroding blanket peat catchment in the Peak District, southern Pennines, UK. Concentrations of lead in the near‐surface peat layer at UNG are in excess of 1000 mg kg−1. For peatland environments, these lead concentrations are some of the highest globally. High concentrations of industrially derived, atmospherically transported magnetic spherules are also stored in the near‐surface peat layer. Samples of suspended sediment taken during a storm event that occurred on 1 November 2002 at UNG, and of the potential catchment sources for suspended sediments, were analysed for lead content and the environmental magnetic properties of anhysteretic remanent magnetization (ARM) and saturation isothermal remanent magnetization (SIRM). At the beginning of the storm event, there is a peak in both suspended sediment and associated lead concentration. SIRM/ARM values for suspended sediment samples throughout the storm reveal that the initial ‘lead flush’ is associated with a specific sediment source, namely that of organic sediment eroded from the upper peat layer. Using the magnetic ‘fingerprinting’ approach to discrimination of sediment sources, this study reveals that erosion of the upper peat layer at UNG is releasing high concentrations of industrially derived lead (and, by inference, other toxic heavy metals associated with industrial particulates) into the fluvial systems of the southern Pennines. Climate‐change scenarios for the UK, involving higher summer temperatures and stormier winters, may result in an increased flux both of sediment‐associated and dissolved heavy metals from eroding peatland catchments in the southern Pennines, adversely affecting the quality of sediment and water entering reservoirs of the region. Copyright © 2005 John Wiley & Sons, Ltd.
An unbiased population‐based search for the geometry optimization of Lennard–Jones clusters: 2 ≤ N ≤ 372
Authors: Pullan Wayne 
Published: April 2005

AbstractThis article presents the results obtained using an unbiased Population Based Search (PBS) for optimizing Lennard–Jones clusters. PBS is able to repeatedly obtain all putative global minima, for Lennard–Jones clusters in the range 2 ≤ N ≤ 372, as reported in the Cambridge Cluster Database. The PBS algorithm incorporates and extends key techniques that have been developed in other Lennard–Jones optimization algorithms over the last decade. Of particular importance are the use of cut‐and‐paste operators, structure niching (using the cluster strain energy as a metric), two‐phase local search, and a new operator, Directed Optimization, which extends the previous concept of directed mutation. In addition, PBS is able to operate in a parallel mode for optimizing larger clusters. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 899–906, 2005
Enhancing rAAV vector expression in the lung
Authors: Virella‐Lowell Isabel , Zusman Benjamin , Foust Kevin , Loiler Scott , Conlon Thomas , Song Sihong , Chesnut Kye A. , Ferkol Thomas , Flotte Terence R. 
Published: April 2005

AbstractDespite favorable DNA transfer efficiency, gene expression from recombinant adeno‐associated virus (rAAV2) vectors in the lung has been variable in the context of cystic fibrosis (CF) gene therapy. This is due, in part, to the large size of the CF transmembrane regulator (CFTR)‐coding sequence which necessitates the use of compact endogenous promoter elements versus stronger exogenous promoters. We evaluated the possibility that gene expression from rAAV could be improved by using AAV capsid serotypes with greater tropism for the apical surface of airway cells (i.e. rAAV5 or rAAV1) and/or using strong promoters such as the cytomegalovirus (CMV) enhancer/chicken beta‐actin hybrid (Cβ) promoter. The relative activity of the CMV immediate‐early (CMVie) promoter, the Cβ promoter, and the Cβ promoter with a downstream woodchuck hepatitis virus post‐transcriptional regulatory element (wpre) were assessed in vitro and in vivo in C57\Bl6 mice using human alpha‐1 antitrypsin (hAAT) as a secreted reporter. In vivo, the Cβ‐AAT‐wpre group achieved maximum serum levels of 1.5 mg/ml of hAAT. AAV capsid serotypes were then compared in vivo utilizing the transcriptionally optimized CB‐wpre cassette in rAAV serotype 1, 2 or 5 capsids (rAAV1, rAAV2, and rAAV5), utilizing luciferase as a reporter to compare expression over a wide dynamic range. The pulmonary luciferase levels at 8 weeks were similar in rAAV5 and rAAV1 groups (2.9 × 106 relative light units (RLU)/g tissue and 2.7 × 106 RLU/g tissue, respectively), both of which were much higher than rAAV2. Although the advantage of rAAV5 over rAAV2 in the lung has already been described, the availability of another serotype (rAAV1) capable of efficient gene transfer in the lung could be useful. Copyright © 2005 John Wiley & Sons, Ltd.
Analysis of flavonoids in leaves of Adinandra nitida by capillary electrochromatography on monolithic columns with stepwise gradient elution
Authors: Zhang Lingyi , Zhang Jie , Wang Hui , Zhang Lihua , Zhang Weibing , Zhang Yukui 
Published: April 2005

AbstractExtracts of Adinandra nitida leaves, known as Shiyacha in China, were analyzed by monolithic columns of capillary electrochromatography (CEC). To obtain good resolution within a short time, stepwise gradient elution of CEC was employed, and the effects of experimental parameters, such as the buffer, the gradient conditions, and the mode of injection were studied systematically. Under optimized conditions, analysis could be accomplished in 25 min on a monolithic rod of macroporous poly(butyl methacrylate–co‐ethylene dimethacrylate). With two identified flavonoids, epicatechin and apigenin, as markers, a quality control method for Shiyacha and its relevant products was established. The calibration curves exhibited good linear behavior over the concentration range of two orders of magnitude. On combination with an on‐line concentration technique, the detection limit of flavonoids could be decreased to 25 ng for apigenin.
Formation of Soluble Hyperbranched Polymer Nanoparticles by Initiator‐Fragment Incorporation Radical Polymerization of Ethylene Glycol Dimethacrylate
Authors: Hirano Tomohiro , Ihara Hiroshi , Miyagi Takashi , Wang Hongwei , Seno Makiko , Sato Tsuneyuki 
Published: April 2005

AbstractSummary: Ethylene glycol dimethacrylate (1) was polymerized at 70 and 80 °C in benzene using high concentrations of the initiator, dimethyl 2,2′‐azobisisobutyrate (2). When the concentrations of 1 and 2 were 0.10 and 0.50 mol · L−1, respectively, the polymerization proceeded homogeneously without any gelation to yield a soluble polymer. The polymerization system involved ESR‐detectable polymer radicals in high concentration (3.1 × 10−6–7.5 × 10−6 mol · L−1 at 70 °C). The polymer formed at 80 °C after 4 h consisted of units of 1 with (4 mol‐%) and without (38 mol‐%) a double bond and a methoxycarbonylpropyl group (58 mol‐%) as the fragment of 2. Thus, the initiator‐fragment incorporation radical polymerization proceeds in the present polymerization to yield a hyperbranched polymer. The polymer showed an upper critical solution temperature (31 °C on cooling and 32 °C on heating) in an acetone/water mixture (4:1 v/v). The intrinsic viscosity of the polymer was very low (0.047 dL · g−1) at 30 °C in benzene despite its considerably high molecular weight ($\overline M _{\rm w}$ = 5.7 × l05 by MALLS). TEM confirmed that the individual polymer molecules were nanoparticles with diameters of 5–15 nm. The polymer was able to solubilize for the dye probe, Rhodamine 6G, by encapsulation in its hyperbranched structure.Hyperbranched structure of the resulting polymer.magnified imageHyperbranched structure of the resulting polymer.
Multicompartment Micelles: Has the Long‐Standing Dream Become a Reality?
Authors: Lutz Jean‐François , Laschewsky André 
Published: April 2005

AbstractSummary: Multicompartment micelles are complex nanosized systems that possess a hydrosoluble shell and a hydrophobic core, which is characterized by segregated incompatible sub‐domains. With roots starting about ten years ago, the field of multicompartment micelles has evolved slowly, until recently when significant achievements have been made. The present article reviews strategies for building such micellar assemblies as well as morphological studies, highlights the future challenges, and discusses possible applications, which exploit the coexistence of differentiated nano‐domains.Formation of multicompartment micelles using miktoarm stars μ‐(polyethylethylene)(poly(ethylene oxide))(poly(perfluoropropylene oxide)) and a cryo‐TEM image visualizing the process.magnified imageFormation of multicompartment micelles using miktoarm stars μ‐(polyethylethylene)(poly(ethylene oxide))(poly(perfluoropropylene oxide)) and a cryo‐TEM image visualizing the process.
Brain‐derived neurotrophic factor gene polymorphisms in Japanese patients with sporadic Alzheimer's disease, Parkinson's disease, and multiple system atrophy
Authors: Nishimura Masataka , Kuno Sadako , Kaji Ryuji , Kawakami Hideshi 
Published: April 2005

AbstractWe studied two genetic polymorphisms (240C/T and 480G/A) of the brain‐derived neurotrophic factor (BDNF) gene in Japanese patients with Alzheimer's disease (AD, n = 172), Parkinson's disease (PD, n = 327), and multiple system atrophy (MSA, n = 122), as well as controls (n = 275). The distribution of the 240 C/T polymorphism was significantly different between AD patients and controls, whereas there was no difference in the genotype of the two polymorphisms between MSA and controls or between PD and controls. Our data suggest that BDNF might play a role in AD. © 2005 Movement Disorder Society
Antioxidant and antigenotoxic effects of plant cell wall hydroxycinnamic acids in cultured HT‐29 cells
Authors: Ferguson Lynnette R. , Zhu Shuo‐tun , Harris Philip J. 
Published: April 2005

AbstractWe demonstrate that two hydroxycinnamic acids, (E )‐ferulic acid and (E )‐p‐coumaric acid, have the ability to protect against oxidative stress and genotoxicity in cultured mammalian cells. They also show the ability to reduce the activity of the xenobiotic metabolising enzyme, cytochrome P450 1A, and downregulate the expression of the cyclooxygenase‐2 enzyme. At equitoxic doses, their activities are equal to or superior to that of the known anticarcinogen, curcumin. The hydroxycinnamic acids are both important components of plant cell walls in certain plant foods. It is known that the action of microbial hydroxycinnamoyl esterases can lead to the release of hydroxycinnamic acids from ester‐linkages to cell wall polysaccharides into the human colon. Thus, providing they can reach effective levels in the colon, they could provide an important mechanism by which dietary fibres of food plants, such as spinach or cereal, protect against colon cancer.
Theoretical estimation of the annular tautomerism of indazoles
Authors: Alkorta Ibon , Elguero José 
Published: April 2005

AbstractTheoretical calculations at semi‐empirical AM1 and density functional B3LYP/6–31G* levels were carried out on 52 NH‐indazoles. Although in most cases the 1H‐tautomer is the most stable, we found several indazoles for which the 2H‐tautomer is more stable than the 1H‐tautomer. The differences in energy between the 1H‐ and 2H‐tautomers were interpreted in terms of substituent effects with the use of a Free–Wilson (presence–absence) matrix. Copyright © 2005 John Wiley & Sons, Ltd.