bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal‐hydrodynamic modeling of bubbly flows with heat and mass transfer
Authors: Yeoh G. H. , Tu J. Y. 
Published: December 2004

AbstractA three‐dimensional (3‐D) two‐fluid model coupled with the population balance equation is used to predict bubbly flows with the presence of heat and mass transfer processes, particularly on subcooled boiling flows at low pressures. To account for the nonuniform bubble distribution in the bulk liquid at subcooled conditions, the CFX MUSIG (MUltiple‐Size Group) model is further developed by incorporating the wall nucleation at the heated wall and condensation in the flow regime. Model predictions, covering a wide range of different mass and heat fluxes and inlet subcooling temperatures, are compared against local and axial measurements. For the local case, the bubble size predictions include the comparison of the empirical bubble diameter relationships adopted in the CFX boiling model. The study shows that good agreement is better achieved by the present model with respect to the radial distributions of the bubble Sauter diameter, void fraction, interfacial area concentration, and liquid velocity profiles. However, significant weakness prevails over the vapor velocity distribution. Work is in progress to circumvent the deficiency by considering additional momentum equations or developing an algebraic slip model to account for bubble separation. For the axial case, good agreement is also achieved for the axial distributions of the mean bubble Sauter diameter, void fraction, and interfacial area concentration profiles. Here, the model correctly represents the plateau at the initial boiling stages at upstream, typically found in low‐pressure subcooled boiling flows, followed by the significant increase of the void fraction at downstream. © 2004 American Institute of Chemical Engineers AIChE J, 51: 8–27, 2005
Automatic crosslingual thesaurus generated from the Hong Kong SAR Police Department Web corpus for crime analysis
Authors: Li Kar Wing , Yang Christopher C. 
Published: December 2004

AbstractFor the sake of national security, very large volumes of data and information are generated and gathered daily. Much of this data and information is written in different languages, stored in different locations, and may be seemingly unconnected. Crosslingual semantic interoperability is a major challenge to generate an overview of this disparate data and information so that it can be analyzed, shared, searched, and summarized. The recent terrorist attacks and the tragic events of September 11, 2001 have prompted increased attention on national security and criminal analysis. Many Asian countries and cities, such as Japan, Taiwan, and Singapore, have been advised that they may become the next targets of terrorist attacks. Semantic interoperability has been a focus in digital library research. Traditional information retrieval (IR) approaches normally require a document to share some common keywords with the query. Generating the associations for the related terms between the two term spaces of users and documents is an important issue. The problem can be viewed as the creation of a thesaurus. Apart from this, terrorists and criminals may communicate through letters, e‐mails, and faxes in languages other than English. The translation ambiguity significantly exacerbates the retrieval problem. The problem is expanded to crosslingual semantic interoperability. In this paper, we focus on the English/Chinese crosslingual semantic interoperability problem. However, the developed techniques are not limited to English and Chinese languages but can be applied to many other languages. English and Chinese are popular languages in the Asian region. Much information about national security or crime is communicated in these languages. An efficient automatically generated thesaurus between these languages is important to crosslingual information retrieval between English and Chinese languages. To facilitate crosslingual information retrieval, a corpus‐based approach uses the term co‐occurrence statistics in parallel or comparable corpora to construct a statistical translation model to cross the language boundary. In this paper, the text‐based approach to align English/Chinese Hong Kong Police press release documents from the Web is first presented. We also introduce an algorithmic approach to generate a robust knowledge base based on statistical correlation analysis of the semantics (knowledge) embedded in the bilingual press release corpus. The research output consisted of a thesaurus‐like, semantic network knowledge base, which can aid in semantics‐based crosslingual information management and retrieval.
User acceptance of Intelligence and Security Informatics technology: A study of COPLINK
Authors: Jen‐Hwa Hu Paul , Lin Chienting , Chen Hsinchun 
Published: December 2004

AbstractThe importance of Intelligence and Security Informatics (ISI) has significantly increased with the rapid and large‐scale migration of local/national security information from physical media to electronic platforms, including the Internet and information systems. Motivated by the significance of ISI in law enforcement (particularly in the digital government context) and the limited investigations of officers' technology‐acceptance decision‐making, we developed and empirically tested a factor model for explaining law‐enforcement officers' technology acceptance. Specifically, our empirical examination targeted the COPLINK technology and involved more than 280 police officers. Overall, our model shows a good fit to the data collected and exhibits satisfactory power for explaining law‐enforcement officers' technology acceptance decisions. Our findings have several implications for research and technology management practices in law enforcement, which are also discussed.
Zerstörungsfreie Untersuchungen an Fundamentplatten mit Ultraschallecho
Authors: Taffe Alexander , Niederleithinger Ernst , Krause Martin , Milmann Boris 
Published: December 2004

AbstractZerstörungsfreie Prüfverfahren im Bauwesen (ZfP‐Bau) dienen der Zustandsermittlung von Bauteilen und der Erkundung unzureichend dokumentierter Bausubstanz. Zur Untersuchung von Fundamentplatten wird das Ultraschallecho‐Verfahren vorgestellt. Es werden Anwendungshinweise zur Durchführung von Dickenmessungen, dem Lokalisieren von Pfählen und Streifenfundamenten unter einer Fundamentplatte gegeben. Anwendungsbeispiele für Untersuchungen an 30 cm, 75cm und 125 cm dicken Fundamentplatten mit verschiedenen Bewehrungsgehalten werden beschrieben. Darüber hinaus wird die bildgebende Darstellung der Ergebnisse, z. B. die Abbildung eingebauter Bewehrung, vorgestellt.
Study of the DNA/ethidium bromide interactions on mica surface by atomic force microscope: Influence of the surface friction
Authors: Pastré David , Piétrement Olivier , Zozime Alain , Le Cam Eric 
Published: December 2004

AbstractThe influence of mica surface on DNA/ethidium bromide interactions is investigated by atomic force microscopy (AFM). We describe the diffusion mechanism of a DNA molecule on a mica surface by using a simple analytical model. It appears that the DNA diffusion on a mica surface is limited by the surface friction due to the counterion correlations between the divalent counterions condensed on both mica and DNA surfaces. We also study the structural changes of linear DNA adsorbed on mica upon ethidium bromide binding by AFM. It turns out that linear DNA molecules adsorbed on a mica surface are unable to relieve the topological constraint upon ethidium bromide binding. In particular, strongly adsorbed molecules tend to be highly entangled, while loosely bound DNA molecules appear more extended with very few crossovers. Adsorbed DNA molecules cannot move freely on the surface because of the surface friction. Therefore, the topological constraint increases due to the ethidium bromide binding. Moreover, we show that ethidium bromide has a lower affinity for strongly bound molecules due to the topological constraint induced by the surface friction. © 2004 Wiley Periodicals, Inc. Biopolymers, 2005
A DFT‐Based Theoretical Investigation of the Mechanism of the PtCl2‐Mediated Cycloisomerization of Allenynes
Authors: Soriano Elena , Marco‐Contelles José 
Published: December 2004

AbstractThe mechanism of PtII‐catalyzed intramolecular cycloisomerization of allenyne systems has been extensively investigated by DFT calculations. Different mechanistic schemes have been proposed and discussed, including the Alder–ene reaction. The free energy results suggest that the kinetically preferred reaction pathway for precursors that are tri‐ and tetrasubstituted on the allene moiety should proceed by a five‐step mechanism. This would involve formation of a platina(IV)cyclopentene intermediate by selective engagement of the external π bond of the allene, which would undergo regioselective β‐H elimination from the equatorially disposed methyl group. A metal‐induced H migration leads to a second octahedral PtIV–chelate complex, which would yield the expected bicyclic system through an intramolecular migratory insertion step. Therefore, depending on the conformation of the initial η4‐reactant complex for trisubstituted patterns, two possible intermediates can be formed that would evolve through different paths. In these cases, the regio‐ and stereochemical outcomes predicted by the mechanistic scheme proposed agree with experimental data. Substituted precursors on the alkyne moiety follow a distinct, four‐step, mechanism also involving an oxidative cyclometalation process to an octahedral PtIV intermediate complex. Theoretical results reveal the kinetic preference for β‐H elimination from the allylic group rather than from the gem‐dimethyl group, which should account for the observed regioselectivity.
Decomposition of Neutral, Singly and Doubly Protonated Benzoquinone in the Gas Phase
Authors: Roithová Jana , Schröder Detlef , Schwarz Helmut 
Published: December 2004

AbstractThe unimolecular fragmentations of singly and doubly protonated ortho‐, meta‐, and para‐benzoquinones (BQH+ and BQH22+, respectively) are studied by tandem mass spectrometry. The dominant fragmentation pathways lead to the elimination of a neutral CO molecule from BQH+ and, by charge separation, to the expulsion of protonated CO from BQH22+. Reaction mechanisms are elucidated based on labeling experiments and UB3 LYP calculations. These results reveal that the respective reactions proceed in an analogous fashion to the decarbonylation of neutral benzoquinones, which decompose into carbon monoxide and cyclopentadienone. Single protonation facilitates all steps on the reaction pathway with neutral CO and O‐protonated cyclopentadienone as final products. In contrast, double protonation leads to an increase of the barriers for the decomposition yielding CO⋅H+ and O‐protonated cyclopentadienone. This major process of BQH22+ is accompanied by two minor channels, which lead to the elimination of neutral carbon monoxide and water, respectively. The proton affinity of the para‐BQH+ monocation is estimated as 3.6±0.3 eV.
Competition between Superexchange‐Mediated and Sequential Electron Transfer in a Bridged Donor–Acceptor System
Authors: Winters Mikael U. , Pettersson Karin , Mårtensson Jerker , Albinsson Bo 
Published: December 2004

AbstractThe temperature‐ and solvent‐dependence of photoinduced electron‐transfer reactions in a porphyrin‐based donor–bridge–acceptor (DBA) system is studied by fluorescence and transient absorption spectroscopy. Two competing processes occur: sequential and direct superexchange‐mediated electron transfer. In a weakly polar solvent (2‐methyltetrahydrofuran), only direct electron transfer from the excited donor to the appended acceptor is observed, and this process has weak temperature dependence. In polar solvents (butyronitrile and dimethylformamide), both processes are observed and the sequential electron transfer shows strong temperature dependence. In systems where both electron transfer processes are observed, the long‐range superexchange‐mediated process is more than two times faster than the sequential process, even though the donor–acceptor distance is significantly larger in the former case.
Mord, Brandstiftung, Sprengstoffanschläge: Analytische Chemie in der Kriminaltechnik
Authors: Schäfer Thomas 
Published: December 2004

AbstractAuch Liebig trat schon als Sachverständiger im Rahmen eines Mordprozesses vor Gericht auf, um den Ausbruch eines merkwürdigen Brandes zu begutachten. Expertenwissen und moderne Analytik unterstützen auch heute die Arbeit von Polizei und Justiz. Je nach Spurenlage und Fragestellung wird ein breit gefächertes Methodenspektrum zum Einsatz gebracht.
Tödliches Ubiquitin‐Etikett
Authors: Jacoby Petra 
Published: December 2004

AbstractDer diesjährige Chemie‐Nobelpreis wurde an Aaron Ciechanover und Avram Hershko vom Israel Institute of Technology in Haifa sowie an Irwin Rose von der University of California in Irvine vergeben. Ihre bahnbrechenden Entdeckungen darüber, wie Zellen unerwünschte Proteine selektiv zum Abbau markieren, lieferten die Basis für ein völlig neues Forschungsfeld.
Der Christmas‐Faktor
Authors: Roth Klaus 
Published: December 2004

AbstractVerletzungen von Blutgefäßen sind für uns lebensbedrohend, und durch Verletzung entstandene Risse und Löcher müssen schnellstens abgedichtet werden. Durch die Blutstillung wird das Leck zunächst provisorisch verschlossen und durch die Blutgerinnung das Provisorium anschließend versteift, um die Wunde auch dauerhaft abzudichten. Dabei greifen über ein Dutzend als Gerinnungsfaktoren bezeichnete Proteine ein (Tabelle 1) und einer davon, der Faktor IX, wird nach dem kleinen Stephen Christmas benannt, denn durch ihn konnte dieser Faktor erstmals identifiziert werden. Entdecken wir die komplexe Chemie der Blutstillung und ‐gerinnung und wie uns ein kleiner Patient mit “seinem” Faktor bei deren Erforschung geholfen hat.
NiIIRuII and CuIIRuII Coordination Polymers Constructed from [Ru(CN)6]4−
Authors: Shek Iris Pui‐Yee , Yeung Wai‐Fun , Lau Tai‐Chu , Zhang Jing , Gao Song , Szeto Lap , Wong Wing‐Tak 
Published: December 2004

AbstractThe dimetallic compounds [Ni(2,3,2‐tet)]2[Ru(CN)6]·8H2O (1), [Ni(pn)2]2[Ru(CN)6]·5H2O (2) [Ni(tacd)(H2O)]2[Ru(CN)6]·8H2O (3) and {[Cu(dipn)]3[Ru(CN)6]}(ClO4)2·4H2O (4) [2,3,2‐tet = N,N′‐bis(2‐aminoethyl)‐1,3‐propanediamine, pn = 1,3‐diaminopropane, tacd = 1,5,9‐triazacyclododecane, dipn = dipropylenetriamine] have been prepared from the reaction of [Ru(CN)6]4− with [Ni(2,3,2‐tet)]2+, [Ni(pn)2]2+, [Ni(tacd)(H2O)]2+ and [Cu(dipn)]2+, respectively. Compounds 1 and 2 contain a two‐dimensional square network, compound 3 has a one‐dimensional, crossed‐double chain structure, while compound 4 has an unusual, two‐dimensional, double‐edged, honeycomb network. A very weak antiferromagnetic interaction is observed in 2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Preparation and Characterisation of CdII, HgII and PbII Complexes of a Macrodinucleating Hexaaza‐dithiophenolate Ligand
Authors: Lozan Vasile , Kersting Berthold 
Published: December 2004

AbstractThe ligating properties of a Robson‐type 24‐membered macrodinucleating hexaaza‐dithiophenolate ligand towards the heavy metal ions CdII, HgII and PbII have been examined. The complexation of H2LMe with CdCl2 or Cd(OAc)2 in the presence of triethylamine leads to monocationic [(LMe)Cd2(μ‐L′)]+ complexes bearing additional coligands [L′ = Cl− (2) or OAc− (3)]. With Hg(OAc)2 and Pb(OAc)2, the respective dicationic complexes [(LMe)Hg2]2+ (4) and [(LMe)Pb2]2+ (5) were obtained. The latter show no tendency to bind to further coligands. The crystal structure determinations of 2·BPh4 and 3·BPh4 revealed the presence of bowl‐shaped, calixarene‐like [(LMe)Cd2(μ‐L′)]+ cations featuring six‐coordinate CdII ions with N3S2Cl (2) or N3S2O (3) environments. The metal ions in the dications 4 and 5 display highly irregular N3S coordination environments, presumably as a consequence of the steric constraints imposed by the rigid macrocyclic nature of (LMe)2−. All complexes could also be fully characterised by 1H and 13C NMR spectroscopy. These results have thus established the ability of the macrodinucleating polyaza‐dithiophenolate ligand to support the formation of stable dinuclear complexes of toxic heavy metals. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
A new conceptual hierarchy for identifying environmental sustainability metrics
Authors: Jin Xun , High Karen A. 
Published: December 2004

AbstractMetric identification has received growing attention as more alternatives become available for quantifying the sustainability‐oriented performance of a target human activity. Failure to tackle the diversity in these alternatives has given rise to significant difficulties in comparing and interpreting the assessment results obtained from using various metrics. This paper explores some bottlenecks in identifying “appropriate” environmental sustainability metrics that specifically meet the needs of a sustainability assessor. A new conceptual hierarchy “stressor–status–effect–integrality–well‐being” (SSEIW) for metric classification is proposed. This hierarchy categorizes the full range of metrics into five levels, each of which measures the interested environmental outcomes in a different manner. This paper shows that the proposed hierarchy can be applied within the framework of life‐cycle assessment (LCA), which provides a promising solution to “best‐practice” metric identification as well as expanding the LCA applications to the sustainability field. © 2004 American Institute of Chemical Engineers Environ Prog, 2004
EGF‐stimulation activates the nuclear localization signal of SHP‐1
Authors: He Dandan , Song Xi , Liu Lijun , Burk David H. , Zhou G. Wayne 
Published: December 2004

AbstractProtein tyrosine phosphatase SHP‐1 plays a critical role in the regulation of a variety of intracellular signaling pathways. SHP‐1 is predominantly expressed in the cells of hematopoietic origin, and is recognized as a negative regulator of lymphocyte development and activation. SHP‐1 consists of two Src homology 2 (SH2) domains and one protein tyrosine phosphatase (PTP) domain followed by a highly basic C‐terminal tail containing tyrosyl phosphorylation sites. It is unclear how the C‐terminal tail regulates SHP‐1 function. We report the examination of the subcellular localization of a variety of truncated or mutated SHP‐1 proteins fused with enhanced green fluorescent protein (EGFP) protein at either the N‐terminal or the C‐terminal end in different cell lines. Our data demonstrate that a nuclear localization signal (NLS) is located in the C‐terminal tail of SHP‐1 and the signal is primarily defined by three amino‐acid residues (KRK) at the C‐terminus. This signal is generally blocked in the native protein and can be exposed by fusing EGFP at the appropriate position or by domain truncation. We have also revealed that this NLS of SHP‐1 is triggered by epidermal growth factor (EGF) stimulation and mediates translocation of SHP‐1 from the cytosol to the nucleus in COS7 cell lines. These results not only demonstrate the importance of the C‐terminal tail of SHP‐1 in the regulation of nuclear localization, but also provide insights into its role in SHP‐1‐involved signal transduction pathways. J. Cell. Biochem. 94: 944–953, 2005. © 2004 Wiley‐Liss, Inc.
Regucalcin stimulates osteoclast‐like cell formation in mouse marrow cultures
Authors: Yamaguchi Masayoshi , Uchiyama Satoshi 
Published: December 2004

AbstractThe effect of regucalcin, a regulatory protein in intracellular signaling, on osteoclastic cell formation in mouse bone marrow culture is investigated. The bone marrow cells were cultured for 7 days in an α‐minimal essential medium containing either vehicle or regucalcin (10−10–10−8M). Osteoclast‐like cell formation was estimated by staining for tartrate‐resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of regucalcin (10−10–10−8M) caused a remarkable increase in osteoclast‐like multinucleated cells (MNCs). The effect of regucalcin in stimulating osteoclast‐like cell formation was significantly inhibited in the presence of calcitonin (CT; 10−9M), 17β‐estradiol (10−9M), β‐cryptoxanthin (CX; 10−6M), or zinc sulfate (10−4M), which is an anti‐bone resorbing factor. The effect of regucalcin on osteoclast‐like cell formation was not significantly blocked in the presence of cycloheximide, an inhibitor of protein synthesis, or 5,6‐dichloro‐1‐β‐D‐ribofuranosylbenzimidazole (DRB), an inhibitor of transcriptional activity. The effect of parathyroid hormone (10−7M), 1,25‐dihydroxyvitamin D3 (10−7M), prostaglandin E2 (10−5M), or tumor necrosis factor‐α (10 ng/ml) in increasing osteoclast‐like cell formation was significantly enhanced in the presence of regucalcin (10−8M). Moreover, when rat femoral‐diaphyseal or ‐metaphyseal tissues were cultured for 48 h in the presence of regucalcin (10−10–10−8M), the diaphyseal or metaphyseal calcium content was significantly decreased in the presence of regucalcin (10−10–10−8M) in vitro. The consumption of glucose and the production of lactic acid in culture medium by the diaphyseal or metaphyseal tissues was significantly raised in the presence of regucalcin (10−10–10−8M). This study demonstrates that regucalcin directly stimulates osteoclast‐like cell formation in mouse marrow culture in vitro, and that the protein stimulates bone resorption in rat femoral tissues in vitro. © 2004 Wiley‐Liss, Inc.
Quaternized biomass as an anion exchanger for the removal of nitrate and other anions from water
Authors: Namasivayam Chinnaiya , Höll Wolfgang H 
Published: December 2004

AbstractDried Chinese Reed (Miscanthus sinensis), a fast growing plant, was used as a model biomass for the development of anion exchangers using a quaternization agent, N‐(3‐chloro‐2‐hydroxypropyl)trimethylammonium chloride (CHMAC), and a cross‐linking agent, epichlorohydrin. Anions studied include nitrate, phosphate, perchlorate and sulfate. Batch mode adsorption studies were conducted using aqueous solutions of anions. Detailed kinetics were studied for nitrate removal. Parameters studied included anion concentration, agitation time, adsorbent dose, and pH. Adsorption equilibrium occurred in 10 min for all the anions studied. Equilibrium adsorption data followed both Langmuir and Freundlich isotherms. The presence of phosphate, perchlorate, fluoride and sulfate lowered the adsorption significantly. The effects of pH on adsorption and desorption show that ion exchange is involved in the adsorption process. The adsorption capacity of the cross‐linked and quaternized Chinese Reed for nitrate, sulfate, phosphate and perchlorate was found to be 7.55, 13.25, 16.61 and 10.07 mg of anion per g of the anion exchanger, respectively. Copyright © 2004 Society of Chemical Industry