bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of high‐frequency optical oscillation during the flare phase of EV Lac in 1999
Authors: Contadakis M. E. , Avgoloupis S. , Seiradakis J. , Zhilyaev B. E. , Romanyuk Ya. O. , Verlyuk I. A. , Svyatogorov O. A. , Khalack V. R. , Sergeev A. V. , Konstantinova‐Antova R. K. , Antov A. P. , Bachev R. S. , Alekseev I. Y. , Chalenko V. E. , Shakhovskoy D. N. 
Published: May 2004

AbstractA program of Many‐sites Multi Channel simultaneous observations of flare stars by a network of telescops was initiated in 1998. The purpose of this program is to investigate the fine structure of the flares light‐curve in UBVRI, depressing atmospheric and instrumental noises. In this paper we present the results of the observations on the Flare star EV Lac in the B color, which were carried out at the Stephanion observatory during the campaign of 1999. Discrete Fourier Transform analysis of the B‐light curve of the largest flares reveal the presence of high frequency small amplitude oscillations with periods ranging between 6.9 sec and 20 sec in around the flare maximum phase. The oscillation amplitude ranges from 1.4 to 2.6 % of the star brightness in accordance with the results of the campaign of 1998 (Zhilyaev et al. 2000). In addition there is a tendency the higher frequencies to persist in the late phases of the flare evolution. The observations are consistent with the phenomenology of the evolution of a fast mode magneto‐acoustic wave generated at the impulsive phase of the flare and traveling through the magnetic loop. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A search for luminous Be stars
Authors: Negueruela I. 
Published: May 2004

AbstractAs Be stars are restricted to luminosity classes III‐V, but early B‐type stars are believed to evolve into supergiants, it is to be expected that the Be phenomenon disappears at some point in the evolution of a moderately massive star, before it reaches the supergiant phase. As a first stage in an attempt to determine the physical reasons of this cessation, a search of the literature has provided a number of candidates to be Be stars with luminosity classes Ib or II. Spectroscopy has been obtained for candidates in a number of open clusters and associations, as well as several other bright stars in those clusters. Among the objects observed, HD 207329 is the best candidate to be a high‐luminosity Be star, as it appears like a fast‐rotating supergiant with double‐peaked emission lines. The lines of HD 229059, in Berkeley 87, also appear morphologically similar to those of Be stars, but there are reasons to suspect that this object is an interacting binary. At slightly lower luminosities, LS I +56°92 (B4 II) and HD 333452 (O9 II), also appear as intrinsically luminous Be stars. Two Be stars in NGC 6913, HD 229221 and HD 229239, appear to have rather higher intrinsic magnitudes than their spectral type (B0.2 III in both cases) would indicate, being as luminous as luminosity class II objects in the same cluster. HD 344863, in NGC 6823, is also a rather early Be star of moderately high luminosity. The search shows that, though high‐luminosity Be stars do exist, they are scarce and, perhaps surprisingly, tend to have early spectral types. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Durchstanzmodell für Flachdecken mit Faserverbundbewehrung und großen Aussparungen in Stützennähe
Authors: Gastmeyer Ralf 
Published: May 2004

AbstractPunktförmig gestützte Deckenplatten mit einer Biegezugbewehrung aus glas‐ oder kohlefaserverstärktem Kunststoff besitzen gegenüber konventionellen Stahlbeton‐Flachdecken deutlich geringere Durchstanztragfähigkeiten [1]. Ursache hierfür ist die Abhängigkeit des Querkrafttragmechanismus im gerissenen Zustand von der Dehnsteifigkeit und damit vom Elastizitätsmodul der Bewehrung, der z. B. bei glasfaserverstärktem Kunststoff mit einem Wert von etwa 35000 N/mm2 höchstens ein Sechstel des Elastizitätsmoduls von Betonstahl beträgt. Bisher geltende Bemessungsvorschriften erlauben jedoch keine direkte Berücksichtigung dieses Einflusses. Es wird ein Modell für die Ermittlung der Durchstanzlast vorgestellt, das im Vergleich zu den in DIN 1045 [2] und in DIN 1045‐1 [3] festgelegten Berechnungsansätzen den Elastizitätsmodul der Biegezugbewehrung direkt erfaßt und auch die tragfähigkeitsmindernde Wirkung von Deckenaussparungen im Auflagerbereich wirklichkeitsnäher als bisher berücksichtigt.
Apoptosis initiated by dependence receptors: a new paradigm for cell death?
Authors: Porter Alan G. , Dhakshinamoorthy Saravanakumar 
Published: May 2004

AbstractA distinct group of receptors including DCC, UNC5, RET and Ptc1 is known to function in ligand‐dependent neuronal growth and differentiation or axon guidance. Acting as “dependence receptors”, they may also regulate neuronal cell survival by inducing apoptosis in the absence of cognate ligand. Receptor‐initiated apoptosis requires proteolytic (caspase) cleavage and exposure of a pro‐apoptotic region in the cytoplasmic domains of the receptors. In contrast, classical apoptosis induced by growth factor or cytokine deprivation involves loss of survival signaling without receptor cleavage. DCC, UNC5, RET and Ptc1 are downregulated or mutated in diverse cancers, and show properties characteristic of tumor suppressors, consistent with their ability to promote neuronal cell death. Dysfunctional dependence receptors have been linked to the loss of specific neurons in certain inherited and neurodegenerative diseases. Dependence receptor‐initiated apoptosis represents a novel paradigm for the controlled removal of specific cells during neural development and elimination of malignant cells that have strayed beyond regions of ligand availability. BioEssays 26:656–664, 2004. © 2004 Wiley Periodicals, Inc.
Synthesis of immune modulators by smooth muscles
Authors: Singer Cherie A. , Salinthone Sonemany , Baker Kimberly J. , Gerthoffer William T. 
Published: May 2004

AbstractThe primary function of smooth muscle cells is to contract and alter the stiffness or diameter of hollow organs such as blood vessels, the airways and the gastrointestinal and urogenital tracts. In addition to purely structural functions, smooth muscle cells may play important metabolic roles, particularly in various inflammatory responses. In cell culture, these cells have been shown to be metabolically dynamic, synthesizing and secreting extracellular matrix proteins, glycosaminoglycans and a wide variety of cell–cell signaling proteins, such as interleukins, chemokines and peptide growth factors. Secreted cell signaling proteins participate in the inflammatory response of smooth muscle‐containing organs, and some can also stimulate smooth muscle migration, proliferation and contraction. The cellular signaling pathways controlling synthesis of these signaling proteins are similar to those used by cells mediating innate immunity and may contribute to pathogenesis of diverse diseases including atherosclerosis, asthma, inflammatory bowel diseases and preterm labor. Appreciating the role of smooth muscle cells in these diseases may lead to better understanding of the beneficial effects of anti‐inflammatory drugs as well as identification of new targets for anti‐inflammatory therapy. BioEssays 26:646–655, 2004. © 2004 Wiley Periodicals, Inc.
Murine Hermansky–Pudlak syndrome genes: regulators of lysosome‐related organelles
Authors: Li Wei , Rusiniak Michael E. , Chintala Sreenivasulu , Gautam Rashi , Novak Edward K. , Swank Richard T. 
Published: May 2004

AbstractIn the mouse, at least 16 genes regulate vesicle trafficking to specialized lysosome‐related organelles, including platelet dense granules and melanosomes. Fourteen of these genes have been identified by positional cloning. All 16 mouse mutants are models for the genetically heterogeneous human disease, Hermansky–Pudlak Syndrome (HPS). Five HPS genes encode known vesicle trafficking proteins. Nine genes are novel, are found only in higher eukaryotes and encode members of three protein complexes termed BLOCs (Biogenesis of Lysosome‐related Organelles Complexes). Mutations in murine HPS genes, which encode protein co‐members of BLOCs, produce essentially identical phenotypes. In addition to their well‐known effects on pigmentation, platelet function and lysosome secretion, HPS genes control a wide range of physiological processes including immune recognition, neuronal functions and lung surfactant trafficking. Studies of the molecular functions of HPS proteins will reveal important details of vesicle trafficking and may lead to therapies for HPS. BioEssays 26:616–628, 2004. © 2004 Wiley Periodicals, Inc.
hnRNP K: One protein multiple processes
Authors: Bomsztyk Karol , Denisenko Oleg , Ostrowski Jerzy 
Published: May 2004

AbstractSince its original identification as a component of the heterogeneous nuclear ribonucleoprotein (hnRNP) complex, K protein has been found not only in the nucleus but also in the cytoplasm and mitochondria and is implicated in chromatin remodeling, transcription, splicing and translation processes. K protein contains multiple modules that, on one hand, bind kinases while, on the other hand, recruit chromatin, transcription, splicing and translation factors. Moreover, the K‐ protein‐mediated interactions are regulated by signaling cascades. These observations are consistent with K protein acting as a docking platform to integrate signaling cascades by facilitating cross‐talk between kinases and factors that mediate nucleic‐acid‐directed processes. Comparison of K across species reveals that it is an essential factor in metazoans, but not in yeast. Although some of the K protein interactions and functions are conserved in eukaryotes from yeast to man, the mammalian protein seems to play a wider role. The greater diversity of mammalian K protein interactions and function may reflect gain of novel docking sites and expansion evolutionary of gene expression networks. BioEssays 26:629–638, 2004. © 2004 Wiley Periodicals, Inc.
Nitric oxide and the enigma of cardiac hypertrophy
Authors: Kempf Tibor , Wollert Kai C. 
Published: May 2004

AbstractIn pathological conditions associated with persistent increases in hemodynamic workload (old myocardial infarction, high blood pressure, valvular heart disease), a number of signalling pathways are activated in the heart, all of which promote hypertrophic growth of the heart, characterised at the cellular level by increases in individual cardiac myocyte size. Some of these pathways are required for a successful adaptation to cardiac injury. Other pathways are maladaptive, however, as they lead to progressive contractile dysfunction and heart failure. The free radical gas nitric oxide and natriuretic peptides, both of which are produced in the heart, have emerged as endogenous inhibitors of maladaptive hypertrophy signalling. Overall, it appears that cardiac hypertrophy is controlled by an interplay of pro‐ and antihypertrophic signalling networks. This delicate balance can tip towards adaptation or heart failure. In the future, patients living with cardiac disease may benefit from therapeutic strategies targeting maladaptive hypertrophy signalling pathways. BioEssays 26:608–615, 2004. © 2004 Wiley Periodicals, Inc.
The androgen receptor mRNA
Authors: Yeap Bu B. , Wilce Jackie A. , Leedman Peter J. 
Published: May 2004

AbstractAndrogens (testosterone), acting via the androgen receptor (AR) a nuclear transcription factor, regulate male sexual development and body composition. In addition, AR expression plays an important role in the proliferation of human prostate cancer and confers a better prognosis in breast cancer. AR mRNA stability is central to the regulation of AR expression in prostate and breast cancer cells, and recent studies have demonstrated binding by members of the ELAV/Hu and poly(C) RNA‐binding protein families to a highly conserved UC‐rich element in the 3′‐untranslated region of AR mRNA, with functional impact on AR protein expression. Remarkably, a CAG trinucleotide repeat in exon 1 of the AR, the length of which has been linked to prostate cancer survival, is also a target for multiple RNA‐binding proteins from a variety of human and murine tissues. In this review, we will detail the current knowledge of the mechanisms involved in regulating AR mRNA stability, the nature, potential role and structural biology of several novel AR mRNA–protein interactions, and the implications for novel therapeutics in human prostate cancer. BioEssays 26:672–682, 2004. © 2004 Wiley Periodicals, Inc.
A new bone to pick: osteoblasts and the haematopoietic stem‐cell niche
Authors: Zhu Jiang , Emerson Stephen G. 
Published: May 2004

AbstractTwo recent publications highlight the role of bone‐forming cells, the osteoblasts, in controlling the development of neighboring haematopoietic stem cells (HSCs).1,2 Using two distinct transgenic mouse models, one using the conditional deletion of the Bone Morphogenetic Protein Receptor 1A (BMPR1A) gene, the other using over‐expression of an active PTH/PTHrP receptor (PPR) mutant within osteoblasts, the authors show parallel, concordant increases in the generation of trabecular osteoblasts and the number of HSCs. In situ staining showed that rarely cycling HSCs sporadically attach to endosteal osteoblasts, while in vitro assays indicated that ligation of Jag1 on osteoblasts by Notch1 on HSCs promotes HSC proliferation. These two independent works have revived and revitalized the notion that osteoblasts are a major, defining component of the HSC niche within the bone marrow (BM). This minireview discusses these results in the context of other recent studies of mesenchymal cells within the BM microenvironment, presents one potential unified model of the functional anatomy of the BM HSC niche, and highlights new questions raised by these and other studies of osteoblasts and HSCs. BioEssays 26:595–599, 2004. © 2004 Wiley Periodicals, Inc.
Growth and specification: fly Pax6 homologs eyegone and eyeless have distinct functions
Authors: Rodrigues Aloma B. , Moses Kevin 
Published: May 2004

AbstractDevelopment requires not only the correct specification of organs and cell types in the right places (pattern), but also the control of their size and shape (growth). Many signaling pathways control both pattern and growth and how these two are distinguished has been something of a mystery. In the fly eye, a Pax6 homolog (eyeless) controls eye specification together with several other genes. Now Dominguez et al.1 show that Notch signaling controls eye growth through a second Pax6 protein (Eyegone). In mice and humans the single Pax6 gene appears to encode both specification and growth controlling proteins through alternative mRNA splicing. BioEssays 26:600–603, 2004. © 2004 Wiley Periodicals, Inc.
Characterization of the conformational behavior of peptide Contryphan Vn: A theoretical study
Authors: D'Alessandro M. , Paci M. , Amadei A. 
Published: May 2004

AbstractIn this work we report the study of a peptide, the Contryphan Vn produced by Conus ventricosus, a vermivorous cone snail living in the temperate Mediterranean sea. This cyclic peptide of nine residues is a ring closed by a Cys–Cys (Cys: cysteine) disulfide bond containing two proline (Pro) residues and two tryptophans (Trp), one of them being a D‐Trp. We present a statistical mechanical characterization of the peptide, simulated in water for about 200 ns with classical molecular dynamics (MD). In recent years there has been a growing interest in the study of the mechanics and dynamics of biological molecules, and in particular for proteins and peptides, about the relationship between collective motions and the active conformations which exert the biological function. To this aim we used the essential dynamics analysis on the MD trajectory and extracted, from the total fluctuations of the molecule, the dominant dynamical modes responsible of the principal conformational transitions. The Contryphan Vn small size allowed us to investigate in details the all‐atoms dynamics and the corresponding thermodynamics in conformational space defined by the most significant intramolecular motions. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Meta-analysis of short-term outcomes after laparoscopic resection for colorectal cancer
Authors: Abraham N S , Young J M , Solomon M J 
Published: May 2004

AbstractBackgroundThe safety and efficacy of laparoscopic resection (LR) for colorectal cancer remains to be established.MethodsA meta-analysis of randomized clinical trials comparing the short-term outcomes of laparoscopic with those of open resection for colorectal cancer was undertaken. A literature search was performed for relevant articles published by the end of 2002. Two reviewers independently appraised the trials using a predetermined protocol. Results were analysed using Comprehensive Meta-analysis®.ResultsThe outcomes of 2512 procedures from 12 trials were analysed. LR took on average 32·9 per cent longer to perform than open resection but was associated with lower morbidity rates. Specifically, wound infection rates were significantly lower (odds ratio 0·47 (95 per cent confidence interval 0·28 to 0·80); P = 0·005). In patients undergoing LR, the average time to passage of first flatus was reduced by 33·5 per cent, that to tolerance of a solid diet by 23·9 per cent and that to 80 per cent recovery of peak expiratory flow by 44·3 per cent. Early narcotic analgesia requirements were also reduced by 36·9 per cent, pain at rest by 34·8 per cent and during coughing by 33·9 per cent, and hospital stay by 20·6 per cent. There were no significant differences in perioperative mortality or oncological clearance.ConclusionLR for colorectal cancer is associated with lower morbidity, less pain, a faster recovery and a shorter hospital stay than open resection, without compromising oncological clearance.
Rapid Discovery of Potent Sulfotransferase Inhibitors by Diversity‐Oriented Reaction in Microplates Followed by in situ Screening
Authors: Best Michael D. , Brik Ashraf , Chapman Eli , Lee Lac V. , Cheng Wei‐Chieh , Wong Chi‐Huey 
Published: May 2004

AbstractRapid diversity‐oriented microplate library synthesis and in situ screening with a high‐throughput fluorescence‐based assay were used to develop potent inhibitors of β‐arylsulfotransferase IV (β‐AST‐IV). This strategy leads to facile inhibitor synthesis and study as it allows protecting‐group manipulation and product isolation from other library components to be avoided. Through repeated library formation, three aspects of inhibitor makeup, the identities of the two binding groups and the length of the linker between them, were independently optimized. Several potent inhibitors were obtained, one of which was determined to have an inhibition constant Ki of 5 nM. This compound is the most potent β‐AST‐IV inhibitor developed to date, with a Ki value more than five orders of magnitude lower than the Michaelis constant Km for the substrate whose binding it inhibits.
Mechanism of the Hydrogen Transfer from the OH Group to Oxygen‐Centered Radicals: Proton‐Coupled Electron‐Transfer versus Radical Hydrogen Abstraction
Authors: Olivella Santiago , Anglada Josep M. , Solé Albert , Bofill Josep M. 
Published: May 2004

AbstractHigh‐level ab initio electronic structure calculations have been carried out with respect to the intermolecular hydrogen‐transfer reaction HCOOH+.OH→HCOO.+H2O and the intramolecular hydrogen‐transfer reaction.OOCH2OH→HOOCH2O.. In both cases we found that the hydrogen atom transfer can take place via two different transition structures. The lowest energy transition structure involves a proton transfer coupled to an electron transfer from the ROH species to the radical, whereas the higher energy transition structure corresponds to the conventional radical hydrogen atom abstraction. An analysis of the atomic spin population, computed within the framework of the topological theory of atoms in molecules, suggests that the triplet repulsion between the unpaired electrons located on the oxygen atoms that undergo hydrogen exchange must be much higher in the transition structure for the radical hydrogen abstraction than that for the proton‐coupled electron‐transfer mechanism. It is suggested that, in the gas phase, hydrogen atom transfer from the OH group to oxygen‐centered radicals occurs by the proton‐coupled electron‐transfer mechanism when this pathway is accessible.
Ruthenium(II) as a Novel “Labile” Partner in Thermodynamic Self‐Assembly of Heterobimetallic d–f Triple‐Stranded Helicates
Authors: Torelli Stéphane , Delahaye Sandra , Hauser Andreas , Bernardinelli Gérald , Piguet Claude 
Published: May 2004

AbstractUnsymmetrical substituted bidentate benzimidazol‐2‐ylpyridine ligands L2 and L3 react with [Ru(dmso)4Cl2] in ethanol to give statistical 1:3 mixtures of fac‐[Ru(Li)3]2+ and mer‐[Ru(Li)3]2+ (i=2, 3; ΔG⊖isomerisation=−2.7 kJ mol−1). In more polar solvents (acetonitrile, methanol), the free energy of the facial⇌meridional isomerisation process favours mer‐[Ru(Li)3]2+, which is the only isomer observed in solution at the equilibrium (ΔG⊖isomerisation≤−11.4 kJ mol−1). Since the latter process takes several days for [Ru(L2)3]2+, fac‐[Ru(L2)3]2+ and mer‐[Ru(L2)3]2+ have been separated by chromatography, but the 28‐fold increase in velocity observed for [Ru(L3)3]2+ provides only mer‐[Ru(L3)3](ClO4)2 after chromatography (RuC60H51N9O8Cl2, monoclinic, P21/n, Z=4). The facial isomer can be stabilised when an appended tridentate binding unit, connected at the 5‐position of the benzimidazol‐2‐ylpyridine unit in ligand L1, interacts with nine‐coordinate lanthanides(III). The free energy of the facial⇌meridional isomerisation is reversed (ΔG⊖isomerisation≥11.4 kJ mol−1), and the RuN bonds are labile enough to allow the quantitative thermodynamic self‐assembly of HHH‐[RuLu(L1)3]5+ within hours ([RuLu(L1)3](CF3SO3)4.5Cl0.5(CH3OH)2.5: RuLuC106H109Cl0.5N21O19S4.5F13.5, triclinic, P$\bar 1$, Z=2). Electrochemical and photophysical studies show that the benzimidazol‐2‐ylpyridine units in L1–L3 display similar π‐acceptor properties to, but stronger π‐donor properties than, those found in 2,2′‐bipyridine. This shifts the intraligand π→π* and the MLCT transitions toward lower energies in the pseudo‐octahedral [Ru(Li)3]2+ (i=2, 3) chromophores. The concomitant short lifetime of the 3MLCT excited state points to efficient, thermally activated quenching via low‐energy Ru‐centred d–d states, a limitation which is partially overcome by mechanical coupling in HHH‐[RuLu(L1)3]5+.